[gnus] / texi / gnus.texi

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* Gnus: (gnus).         The newsreader Gnus.
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Copyright \copyright{} 1995,96,97,98,99,2000 Free Software Foundation, Inc.


Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
any later version published by the Free Software Foundation; with no
Invariant Sections, with the Front-Cover texts being ``A GNU
Manual'', and with the Back-Cover Texts as in (a) below.  A copy of the
license is included in the section entitled ``GNU Free Documentation
License'' in the Emacs manual.

(a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify
this GNU Manual, like GNU software.  Copies published by the Free
Software Foundation raise funds for GNU development.''

This document is part of a collection distributed under the GNU Free
Documentation License.  If you want to distribute this document
separately from the collection, you can do so by adding a copy of the
license to the document, as described in section 6 of the license.
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@ifnottex

This file documents Gnus, the GNU Emacs newsreader.

Copyright (C) 1995,96,97,98,99,2000 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
any later version published by the Free Software Foundation; with the
Invariant Sections being none, with the Front-Cover texts being ``A GNU
Manual'', and with the Back-Cover Texts as in (a) below.  A copy of the
license is included in the section entitled ``GNU Free Documentation
License'' in the Emacs manual.

(a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify
this GNU Manual, like GNU software.  Copies published by the Free
Software Foundation raise funds for GNU development.''

This document is part of a collection distributed under the GNU Free
Documentation License.  If you want to distribute this document
separately from the collection, you can do so by adding a copy of the
license to the document, as described in section 6 of the license.
@end ifnottex

@tex

@titlepage
@title Gnus Manual

@author by Lars Magne Ingebrigtsen
@page

@vskip 0pt plus 1filll
Copyright @copyright{} 1995,96,97,98,99,2000 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
any later version published by the Free Software Foundation; with no
Invariant Sections, with the Front-Cover texts being ``A GNU
Manual'', and with the Back-Cover Texts as in (a) below.  A copy of the
license is included in the section entitled ``GNU Free Documentation
License'' in the Emacs manual.

(a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify
this GNU Manual, like GNU software.  Copies published by the Free
Software Foundation raise funds for GNU development.''

This document is part of a collection distributed under the GNU Free
Documentation License.  If you want to distribute this document
separately from the collection, you can do so by adding a copy of the
license to the document, as described in section 6 of the license.

@end titlepage
@page

@end tex


@node Top
@top The Gnus Newsreader

@ifinfo

You can read news (and mail) from within Emacs by using Gnus.  The news
can be gotten by any nefarious means you can think of---@sc{nntp}, local
spool or your mbox file.  All at the same time, if you want to push your
luck.

This manual corresponds to Oort Gnus v0.01.

@end ifinfo

@iftex

@iflatex
\tableofcontents
\gnuscleardoublepage
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Gnus is the advanced, self-documenting, customizable, extensible
unreal-time newsreader for GNU Emacs.

Oops.  That sounds oddly familiar, so let's start over again to avoid
being accused of plagiarism:

Gnus is a message-reading laboratory.  It will let you look at just
about anything as if it were a newsgroup.  You can read mail with it,
you can browse directories with it, you can @code{ftp} with it---you
can even read news with it!

Gnus tries to empower people who read news the same way Emacs empowers
people who edit text.  Gnus sets no limits to what the user should be
allowed to do.  Users are encouraged to extend Gnus to make it behave
like they want it to behave.  A program should not control people;
people should be empowered to do what they want by using (or abusing)
the program.

@end iftex

@menu
* Starting Up::           Finding news can be a pain.
* The Group Buffer::      Selecting, subscribing and killing groups.
* The Summary Buffer::    Reading, saving and posting articles.
* The Article Buffer::    Displaying and handling articles.
* Composing Messages::    Information on sending mail and news.
* Select Methods::        Gnus reads all messages from various select methods.
* Scoring::               Assigning values to articles.
* Various::               General purpose settings.
* The End::               Farewell and goodbye.
* Appendices::            Terminology, Emacs intro, FAQ, History, Internals.
* Index::                 Variable, function and concept index.
* Key Index::             Key Index.

@detailmenu
 --- The Detailed Node Listing ---

Starting Gnus

* Finding the News::    Choosing a method for getting news.
* The First Time::      What does Gnus do the first time you start it?
* The Server is Down::  How can I read my mail then?
* Slave Gnusae::        You can have more than one Gnus active at a time.
* Fetching a Group::    Starting Gnus just to read a group.
* New Groups::          What is Gnus supposed to do with new groups?
* Startup Files::       Those pesky startup files---@file{.newsrc}.
* Auto Save::           Recovering from a crash.
* The Active File::     Reading the active file over a slow line Takes Time.
* Changing Servers::    You may want to move from one server to another.
* Startup Variables::   Other variables you might change.

New Groups

* Checking New Groups::      Determining what groups are new.
* Subscription Methods::     What Gnus should do with new groups.
* Filtering New Groups::     Making Gnus ignore certain new groups.

The Group Buffer

* Group Buffer Format::    Information listed and how you can change it.
* Group Maneuvering::      Commands for moving in the group buffer.
* Selecting a Group::      Actually reading news.
* Group Data::             Changing the info for a group.
* Subscription Commands::  Unsubscribing, killing, subscribing.
* Group Levels::           Levels? What are those, then?
* Group Score::            A mechanism for finding out what groups you like.
* Marking Groups::         You can mark groups for later processing.
* Foreign Groups::         Creating and editing groups.
* Group Parameters::       Each group may have different parameters set.
* Listing Groups::         Gnus can list various subsets of the groups.
* Sorting Groups::         Re-arrange the group order.
* Group Maintenance::      Maintaining a tidy @file{.newsrc} file.
* Browse Foreign Server::  You can browse a server.  See what it has to offer.
* Exiting Gnus::           Stop reading news and get some work done.
* Group Topics::           A folding group mode divided into topics.
* Misc Group Stuff::       Other stuff that you can to do.

Group Buffer Format

* Group Line Specification::       Deciding how the group buffer is to look.
* Group Modeline Specification::   The group buffer modeline.
* Group Highlighting::             Having nice colors in the group buffer.

Group Topics

* Topic Variables::    How to customize the topics the Lisp Way.
* Topic Commands::     Interactive E-Z commands.
* Topic Sorting::      Sorting each topic individually.
* Topic Topology::     A map of the world.
* Topic Parameters::   Parameters that apply to all groups in a topic.

Misc Group Stuff

* Scanning New Messages:: Asking Gnus to see whether new messages have arrived.
* Group Information::     Information and help on groups and Gnus.
* Group Timestamp::       Making Gnus keep track of when you last read a group.
* File Commands::         Reading and writing the Gnus files.

The Summary Buffer

* Summary Buffer Format::       Deciding how the summary buffer is to look.
* Summary Maneuvering::         Moving around the summary buffer.
* Choosing Articles::           Reading articles.
* Paging the Article::          Scrolling the current article.
* Reply Followup and Post::     Posting articles.
* Marking Articles::            Marking articles as read, expirable, etc.
* Limiting::                    You can limit the summary buffer.
* Threading::                   How threads are made.
* Sorting::                     How articles and threads are sorted.
* Asynchronous Fetching::       Gnus might be able to pre-fetch articles.
* Article Caching::             You may store articles in a cache.
* Persistent Articles::         Making articles expiry-resistant.
* Article Backlog::             Having already read articles hang around.
* Saving Articles::             Ways of customizing article saving.
* Decoding Articles::           Gnus can treat series of (uu)encoded articles.
* Article Treatment::           The article buffer can be mangled at will.
* MIME Commands::               Doing MIMEy things with the articles.
* Charsets::                    Character set issues.
* Article Commands::            Doing various things with the article buffer.
* Summary Sorting::             Sorting the summary buffer in various ways.
* Finding the Parent::          No child support? Get the parent.
* Alternative Approaches::      Reading using non-default summaries.
* Tree Display::                A more visual display of threads.
* Mail Group Commands::         Some commands can only be used in mail groups.
* Various Summary Stuff::       What didn't fit anywhere else.
* Exiting the Summary Buffer::  Returning to the Group buffer.
* Crosspost Handling::          How crossposted articles are dealt with.
* Duplicate Suppression::       An alternative when crosspost handling fails.
* Security::                    Decrypt and Verify.

Summary Buffer Format

* Summary Buffer Lines::     You can specify how summary lines should look.
* To From Newsgroups::       How to not display your own name.
* Summary Buffer Mode Line:: You can say how the mode line should look.
* Summary Highlighting::     Making the summary buffer all pretty and nice.

Choosing Articles

* Choosing Commands::        Commands for choosing articles.
* Choosing Variables::       Variables that influence these commands.

Reply, Followup and Post

* Summary Mail Commands::    Sending mail.
* Summary Post Commands::    Sending news.
* Summary Message Commands:: Other Message-related commands.
* Canceling and Superseding:: ``Whoops, I shouldn't have called him that.''

Marking Articles

* Unread Articles::          Marks for unread articles.
* Read Articles::            Marks for read articles.
* Other Marks::              Marks that do not affect readedness.
* Setting Marks::            How to set and remove marks.
* Generic Marking Commands:: How to customize the marking.
* Setting Process Marks::    How to mark articles for later processing.

Threading

* Customizing Threading::    Variables you can change to affect the threading.
* Thread Commands::          Thread based commands in the summary buffer.

Customizing Threading

* Loose Threads::        How Gnus gathers loose threads into bigger threads.
* Filling In Threads::   Making the threads displayed look fuller.
* More Threading::       Even more variables for fiddling with threads.
* Low-Level Threading::  You thought it was over... but you were wrong!

Decoding Articles

* Uuencoded Articles::    Uudecode articles.
* Shell Archives::        Unshar articles.
* PostScript Files::      Split PostScript.
* Other Files::           Plain save and binhex.
* Decoding Variables::    Variables for a happy decoding.
* Viewing Files::         You want to look at the result of the decoding?

Decoding Variables

* Rule Variables::          Variables that say how a file is to be viewed.
* Other Decode Variables::  Other decode variables.
* Uuencoding and Posting::  Variables for customizing uuencoding.

Article Treatment

* Article Highlighting::    You want to make the article look like fruit salad.
* Article Fontisizing::     Making emphasized text look nice.
* Article Hiding::          You also want to make certain info go away.
* Article Washing::         Lots of way-neat functions to make life better.
* Article Buttons::         Click on URLs, Message-IDs, addresses and the like.
* Article Date::            Grumble, UT!
* Article Signature::       What is a signature?
* Article Miscellania::     Various other stuff.

Alternative Approaches

* Pick and Read::               First mark articles and then read them.
* Binary Groups::               Auto-decode all articles.

Various Summary Stuff

* Summary Group Information::         Information oriented commands.
* Searching for Articles::            Multiple article commands.
* Summary Generation Commands::       (Re)generating the summary buffer.
* Really Various Summary Commands::   Those pesky non-conformant commands.

The Article Buffer

* Hiding Headers::        Deciding what headers should be displayed.
* Using MIME::            Pushing articles through @sc{mime} before reading them.
* Customizing Articles::  Tailoring the look of the articles.
* Article Keymap::        Keystrokes available in the article buffer.
* Misc Article::          Other stuff.

Composing Messages

* Mail::                 Mailing and replying.
* Post::                 Posting and following up.
* Posting Server::       What server should you post via?
* Mail and Post::        Mailing and posting at the same time.
* Archived Messages::    Where Gnus stores the messages you've sent.
* Posting Styles::       An easier way to specify who you are.
* Drafts::               Postponing messages and rejected messages.
* Rejected Articles::    What happens if the server doesn't like your article?

Select Methods

* The Server Buffer::     Making and editing virtual servers.
* Getting News::          Reading USENET news with Gnus.
* Getting Mail::          Reading your personal mail with Gnus.
* Browsing the Web::      Getting messages from a plethora of Web sources.
* Other Sources::         Reading directories, files, SOUP packets.
* Combined Groups::       Combining groups into one group.
* Gnus Unplugged::        Reading news and mail offline.

The Server Buffer

* Server Buffer Format::      You can customize the look of this buffer.
* Server Commands::           Commands to manipulate servers.
* Example Methods::           Examples server specifications.
* Creating a Virtual Server:: An example session.
* Server Variables::          Which variables to set.
* Servers and Methods::       You can use server names as select methods.
* Unavailable Servers::       Some servers you try to contact may be down.

Getting News

* NNTP::               Reading news from an @sc{nntp} server.
* News Spool::         Reading news from the local spool.

Getting Mail

* Mail in a Newsreader::         Important introductory notes.  
* Getting Started Reading Mail:: A simple cookbook example.
* Splitting Mail::               How to create mail groups.
* Mail Sources::                 How to tell Gnus where to get mail from.
* Mail Backend Variables::       Variables for customizing mail handling.
* Fancy Mail Splitting::         Gnus can do hairy splitting of incoming mail.
* Group Mail Splitting::         Use group customize to drive mail splitting.
* Incorporating Old Mail::       What about the old mail you have?
* Expiring Mail::                Getting rid of unwanted mail.
* Washing Mail::                 Removing gruft from the mail you get.
* Duplicates::                   Dealing with duplicated mail.
* Not Reading Mail::             Using mail backends for reading other files.
* Choosing a Mail Backend::      Gnus can read a variety of mail formats.

Mail Sources

* Mail Source Specifiers::       How to specify what a mail source is.
* Mail Source Customization::    Some variables that influence things.
* Fetching Mail::                Using the mail source specifiers.

Choosing a Mail Backend

* Unix Mail Box::               Using the (quite) standard Un*x mbox.
* Rmail Babyl::                 Emacs programs use the rmail babyl format.
* Mail Spool::                  Store your mail in a private spool?
* MH Spool::                    An mhspool-like backend.
* Mail Folders::                Having one file for each group.
* Comparing Mail Backends::     An in-depth looks at pros and cons.

Browsing the Web

* Web Searches::          Creating groups from articles that match a string.
* Slashdot::              Reading the Slashdot comments.
* Ultimate::              The Ultimate Bulletin Board systems.
* Web Archive::           Reading mailing list archived on web.

Other Sources

* Directory Groups::      You can read a directory as if it was a newsgroup.
* Anything Groups::       Dired?  Who needs dired?
* Document Groups::       Single files can be the basis of a group.
* SOUP::                  Reading @sc{soup} packets ``offline''.
* Mail-To-News Gateways:: Posting articles via mail-to-news gateways.
* IMAP::                  Using Gnus as a @sc{imap} client.

Document Groups

* Document Server Internals::   How to add your own document types.

SOUP

* SOUP Commands::     Commands for creating and sending @sc{soup} packets
* SOUP Groups::       A backend for reading @sc{soup} packets.
* SOUP Replies::      How to enable @code{nnsoup} to take over mail and news.

@sc{imap}

* Splitting in IMAP::     Splitting mail with nnimap.
* Editing IMAP ACLs::     Limiting/enabling other users access to a mailbox.
* Expunging mailboxes::   Equivalent of a "compress mailbox" button.

Combined Groups

* Virtual Groups::     Combining articles from many groups.
* Kibozed Groups::     Looking through parts of the newsfeed for articles.

Gnus Unplugged

* Agent Basics::           How it all is supposed to work.
* Agent Categories::       How to tell the Gnus Agent what to download.
* Agent Commands::         New commands for all the buffers.
* Agent Expiry::           How to make old articles go away.
* Agent and IMAP::         How to use the Agent with IMAP.
* Outgoing Messages::      What happens when you post/mail something?
* Agent Variables::        Customizing is fun.
* Example Setup::          An example @file{.gnus.el} file for offline people.
* Batching Agents::        How to fetch news from a @code{cron} job.
* Agent Caveats::          What you think it'll do and what it does.

Agent Categories

* Category Syntax::       What a category looks like.
* The Category Buffer::   A buffer for maintaining categories.
* Category Variables::    Customize'r'Us.

Agent Commands

* Group Agent Commands::
* Summary Agent Commands::
* Server Agent Commands::

Scoring

* Summary Score Commands::   Adding score entries for the current group.
* Group Score Commands::     General score commands.
* Score Variables::          Customize your scoring.  (My, what terminology).
* Score File Format::        What a score file may contain.
* Score File Editing::       You can edit score files by hand as well.
* Adaptive Scoring::         Big Sister Gnus knows what you read.
* Home Score File::          How to say where new score entries are to go.
* Followups To Yourself::    Having Gnus notice when people answer you.
* Scoring Tips::             How to score effectively.
* Reverse Scoring::          That problem child of old is not problem.
* Global Score Files::       Earth-spanning, ear-splitting score files.
* Kill Files::               They are still here, but they can be ignored.
* Converting Kill Files::    Translating kill files to score files.
* GroupLens::                Getting predictions on what you like to read.
* Advanced Scoring::         Using logical expressions to build score rules.
* Score Decays::             It can be useful to let scores wither away.

GroupLens

* Using GroupLens::          How to make Gnus use GroupLens.
* Rating Articles::          Letting GroupLens know how you rate articles.
* Displaying Predictions::   Displaying predictions given by GroupLens.
* GroupLens Variables::      Customizing GroupLens.

Advanced Scoring

* Advanced Scoring Syntax::     A definition.
* Advanced Scoring Examples::   What they look like.
* Advanced Scoring Tips::       Getting the most out of it.

Various

* Process/Prefix::             A convention used by many treatment commands.
* Interactive::                Making Gnus ask you many questions.
* Symbolic Prefixes::          How to supply some Gnus functions with options.
* Formatting Variables::       You can specify what buffers should look like.
* Windows Configuration::      Configuring the Gnus buffer windows.
* Faces and Fonts::            How to change how faces look.
* Compilation::                How to speed Gnus up.
* Mode Lines::                 Displaying information in the mode lines.
* Highlighting and Menus::     Making buffers look all nice and cozy.
* Buttons::                    Get tendonitis in ten easy steps!
* Daemons::                    Gnus can do things behind your back.
* NoCeM::                      How to avoid spam and other fatty foods.
* Undo::                       Some actions can be undone.
* Moderation::                 What to do if you're a moderator.
* XEmacs Enhancements::        There are more pictures and stuff under XEmacs.
* Fuzzy Matching::             What's the big fuzz?
* Thwarting Email Spam::       A how-to on avoiding unsolicited commercial email.
* Various Various::            Things that are really various.

Formatting Variables

* Formatting Basics::     A formatting variable is basically a format string.
* Mode Line Formatting::  Some rules about mode line formatting variables.
* Advanced Formatting::   Modifying output in various ways.
* User-Defined Specs::    Having Gnus call your own functions.
* Formatting Fonts::      Making the formatting look colorful and nice.

XEmacs Enhancements

* Picons::    How to display pictures of what your reading.
* Smileys::   Show all those happy faces the way they were meant to be shown.
* Toolbar::   Click'n'drool.
* XVarious::  Other XEmacsy Gnusey variables.

Picons

* Picon Basics::           What are picons and How do I get them.
* Picon Requirements::     Don't go further if you aren't using XEmacs.
* Easy Picons::            Displaying Picons---the easy way.
* Hard Picons::            The way you should do it.  You'll learn something.
* Picon Useless Configuration:: Other variables you can trash/tweak/munge/play with.

Appendices

* History::                        How Gnus got where it is today.
* On Writing Manuals::             Why this is not a beginner's guide.
* Terminology::                    We use really difficult, like, words here.
* Customization::                  Tailoring Gnus to your needs.
* Troubleshooting::                What you might try if things do not work.
* Gnus Reference Guide::           Rilly, rilly technical stuff.
* Emacs for Heathens::             A short introduction to Emacsian terms.
* Frequently Asked Questions::     A question-and-answer session.

History

* Gnus Versions::       What Gnus versions have been released.
* Other Gnus Versions:: Other Gnus versions that also have been released.
* Why?::                What's the point of Gnus?
* Compatibility::       Just how compatible is Gnus with @sc{gnus}?
* Conformity::          Gnus tries to conform to all standards.
* Emacsen::             Gnus can be run on a few modern Emacsen.
* Gnus Development::    How Gnus is developed.
* Contributors::        Oodles of people.
* New Features::        Pointers to some of the new stuff in Gnus.
* Newest Features::     Features so new that they haven't been written yet.

New Features

* ding Gnus::          New things in Gnus 5.0/5.1, the first new Gnus.
* September Gnus::     The Thing Formally Known As Gnus 5.3/5.3.
* Red Gnus::           Third time best---Gnus 5.4/5.5.
* Quassia Gnus::       Two times two is four, or Gnus 5.6/5.7.

Customization

* Slow/Expensive Connection:: You run a local Emacs and get the news elsewhere.
* Slow Terminal Connection::  You run a remote Emacs.
* Little Disk Space::         You feel that having large setup files is icky.
* Slow Machine::              You feel like buying a faster machine.

Gnus Reference Guide

* Gnus Utility Functions::   Common functions and variable to use.
* Backend Interface::        How Gnus communicates with the servers.
* Score File Syntax::        A BNF definition of the score file standard.
* Headers::                  How Gnus stores headers internally.
* Ranges::                   A handy format for storing mucho numbers.
* Group Info::               The group info format.
* Extended Interactive::     Symbolic prefixes and stuff.
* Emacs/XEmacs Code::        Gnus can be run under all modern Emacsen.
* Various File Formats::     Formats of files that Gnus use.

Backend Interface

* Required Backend Functions::        Functions that must be implemented.
* Optional Backend Functions::        Functions that need not be implemented.
* Error Messaging::                   How to get messages and report errors.
* Writing New Backends::              Extending old backends.
* Hooking New Backends Into Gnus::    What has to be done on the Gnus end.
* Mail-like Backends::                Some tips on mail backends.

Various File Formats

* Active File Format::      Information on articles and groups available.
* Newsgroups File Format::  Group descriptions.

Emacs for Heathens

* Keystrokes::      Entering text and executing commands.
* Emacs Lisp::      The built-in Emacs programming language.

@end detailmenu
@end menu

@node Starting Up
@chapter Starting Gnus
@cindex starting up

@kindex M-x gnus
@findex gnus
If your system administrator has set things up properly, starting Gnus
and reading news is extremely easy---you just type @kbd{M-x gnus} in
your Emacs.

@findex gnus-other-frame
@kindex M-x gnus-other-frame
If you want to start Gnus in a different frame, you can use the command
@kbd{M-x gnus-other-frame} instead.

If things do not go smoothly at startup, you have to twiddle some
variables in your @file{~/.gnus} file.  This file is similar to
@file{~/.emacs}, but is read when gnus starts.

If you puzzle at any terms used in this manual, please refer to the
terminology section (@pxref{Terminology}).

@menu
* Finding the News::    Choosing a method for getting news.
* The First Time::      What does Gnus do the first time you start it?
* The Server is Down::  How can I read my mail then?
* Slave Gnusae::        You can have more than one Gnus active at a time.
* Fetching a Group::    Starting Gnus just to read a group.
* New Groups::          What is Gnus supposed to do with new groups?
* Startup Files::       Those pesky startup files---@file{.newsrc}.
* Auto Save::           Recovering from a crash.
* The Active File::     Reading the active file over a slow line Takes Time.
* Changing Servers::    You may want to move from one server to another.
* Startup Variables::   Other variables you might change.
@end menu


@node Finding the News
@section Finding the News
@cindex finding news

@vindex gnus-select-method
@c @head
The @code{gnus-select-method} variable says where Gnus should look for
news.  This variable should be a list where the first element says
@dfn{how} and the second element says @dfn{where}.  This method is your
native method.  All groups not fetched with this method are
foreign groups.

For instance, if the @samp{news.somewhere.edu} @sc{nntp} server is where
you want to get your daily dosage of news from, you'd say:

@lisp
(setq gnus-select-method '(nntp "news.somewhere.edu"))
@end lisp

If you want to read directly from the local spool, say:

@lisp
(setq gnus-select-method '(nnspool ""))
@end lisp

If you can use a local spool, you probably should, as it will almost
certainly be much faster.

@vindex gnus-nntpserver-file
@cindex NNTPSERVER
@cindex @sc{nntp} server
If this variable is not set, Gnus will take a look at the
@code{NNTPSERVER} environment variable.  If that variable isn't set,
Gnus will see whether @code{gnus-nntpserver-file}
(@file{/etc/nntpserver} by default) has any opinions on the matter.  If
that fails as well, Gnus will try to use the machine running Emacs as an @sc{nntp} server.  That's a long shot, though.

@vindex gnus-nntp-server
If @code{gnus-nntp-server} is set, this variable will override
@code{gnus-select-method}.  You should therefore set
@code{gnus-nntp-server} to @code{nil}, which is what it is by default.

@vindex gnus-secondary-servers
@vindex gnus-nntp-server
You can also make Gnus prompt you interactively for the name of an
@sc{nntp} server.  If you give a non-numerical prefix to @code{gnus}
(i.e., @kbd{C-u M-x gnus}), Gnus will let you choose between the servers
in the @code{gnus-secondary-servers} list (if any).  You can also just
type in the name of any server you feel like visiting.  (Note that this
will set @code{gnus-nntp-server}, which means that if you then @kbd{M-x
gnus} later in the same Emacs session, Gnus will contact the same
server.)

@findex gnus-group-browse-foreign-server
@kindex B (Group)
However, if you use one @sc{nntp} server regularly and are just
interested in a couple of groups from a different server, you would be
better served by using the @kbd{B} command in the group buffer.  It will
let you have a look at what groups are available, and you can subscribe
to any of the groups you want to.  This also makes @file{.newsrc}
maintenance much tidier.  @xref{Foreign Groups}.

@vindex gnus-secondary-select-methods
@c @head
A slightly different approach to foreign groups is to set the
@code{gnus-secondary-select-methods} variable.  The select methods
listed in this variable are in many ways just as native as the
@code{gnus-select-method} server.  They will also be queried for active
files during startup (if that's required), and new newsgroups that
appear on these servers will be subscribed (or not) just as native
groups are.

For instance, if you use the @code{nnmbox} backend to read your mail, you
would typically set this variable to

@lisp
(setq gnus-secondary-select-methods '((nnmbox "")))
@end lisp


@node The First Time
@section The First Time
@cindex first time usage

If no startup files exist, Gnus will try to determine what groups should
be subscribed by default.

@vindex gnus-default-subscribed-newsgroups
If the variable @code{gnus-default-subscribed-newsgroups} is set, Gnus
will subscribe you to just those groups in that list, leaving the rest
killed.  Your system administrator should have set this variable to
something useful.

Since she hasn't, Gnus will just subscribe you to a few arbitrarily
picked groups (i.e., @samp{*.newusers}).  (@dfn{Arbitrary} is defined
here as @dfn{whatever Lars thinks you should read}.)

You'll also be subscribed to the Gnus documentation group, which should
help you with most common problems.

If @code{gnus-default-subscribed-newsgroups} is @code{t}, Gnus will just
use the normal functions for handling new groups, and not do anything
special.


@node The Server is Down
@section The Server is Down
@cindex server errors

If the default server is down, Gnus will understandably have some
problems starting.  However, if you have some mail groups in addition to
the news groups, you may want to start Gnus anyway.

Gnus, being the trusting sort of program, will ask whether to proceed
without a native select method if that server can't be contacted.  This
will happen whether the server doesn't actually exist (i.e., you have
given the wrong address) or the server has just momentarily taken ill
for some reason or other.  If you decide to continue and have no foreign
groups, you'll find it difficult to actually do anything in the group
buffer.  But, hey, that's your problem.  Blllrph!

@findex gnus-no-server
@kindex M-x gnus-no-server
@c @head
If you know that the server is definitely down, or you just want to read
your mail without bothering with the server at all, you can use the
@code{gnus-no-server} command to start Gnus.  That might come in handy
if you're in a hurry as well.  This command will not attempt to contact
your primary server---instead, it will just activate all groups on level
1 and 2.  (You should preferably keep no native groups on those two
levels.)


@node Slave Gnusae
@section Slave Gnusae
@cindex slave

You might want to run more than one Emacs with more than one Gnus at the
same time.  If you are using different @file{.newsrc} files (e.g., if you
are using the two different Gnusae to read from two different servers),
that is no problem whatsoever.  You just do it.

The problem appears when you want to run two Gnusae that use the same
@code{.newsrc} file.

To work around that problem some, we here at the Think-Tank at the Gnus
Towers have come up with a new concept: @dfn{Masters} and
@dfn{slaves}.  (We have applied for a patent on this concept, and have
taken out a copyright on those words.  If you wish to use those words in
conjunction with each other, you have to send $1 per usage instance to
me.  Usage of the patent (@dfn{Master/Slave Relationships In Computer
Applications}) will be much more expensive, of course.)

Anyways, you start one Gnus up the normal way with @kbd{M-x gnus} (or
however you do it).  Each subsequent slave Gnusae should be started with
@kbd{M-x gnus-slave}.  These slaves won't save normal @file{.newsrc}
files, but instead save @dfn{slave files} that contain information only
on what groups have been read in the slave session.  When a master Gnus
starts, it will read (and delete) these slave files, incorporating all
information from them.  (The slave files will be read in the sequence
they were created, so the latest changes will have precedence.)

Information from the slave files has, of course, precedence over the
information in the normal (i.e., master) @code{.newsrc} file.


@node Fetching a Group
@section Fetching a Group
@cindex fetching a group

@findex gnus-fetch-group
It is sometimes convenient to be able to just say ``I want to read this
group and I don't care whether Gnus has been started or not''.  This is
perhaps more useful for people who write code than for users, but the
command @code{gnus-fetch-group} provides this functionality in any case.
It takes the group name as a parameter.


@node New Groups
@section New Groups
@cindex new groups
@cindex subscription

@vindex gnus-check-new-newsgroups
If you are satisfied that you really never want to see any new groups,
you can set @code{gnus-check-new-newsgroups} to @code{nil}.  This will
also save you some time at startup.  Even if this variable is
@code{nil}, you can always subscribe to the new groups just by pressing
@kbd{U} in the group buffer (@pxref{Group Maintenance}).  This variable
is @code{ask-server} by default.  If you set this variable to
@code{always}, then Gnus will query the backends for new groups even
when you do the @kbd{g} command (@pxref{Scanning New Messages}).

@menu
* Checking New Groups::      Determining what groups are new.
* Subscription Methods::     What Gnus should do with new groups.
* Filtering New Groups::     Making Gnus ignore certain new groups.
@end menu


@node Checking New Groups
@subsection Checking New Groups

Gnus normally determines whether a group is new or not by comparing the
list of groups from the active file(s) with the lists of subscribed and
dead groups.  This isn't a particularly fast method.  If
@code{gnus-check-new-newsgroups} is @code{ask-server}, Gnus will ask the
server for new groups since the last time.  This is both faster and
cheaper.  This also means that you can get rid of the list of killed
groups altogether, so you may set @code{gnus-save-killed-list} to
@code{nil}, which will save time both at startup, at exit, and all over.
Saves disk space, too.  Why isn't this the default, then?
Unfortunately, not all servers support this command.

I bet I know what you're thinking now: How do I find out whether my
server supports @code{ask-server}?  No?  Good, because I don't have a
fail-safe answer.  I would suggest just setting this variable to
@code{ask-server} and see whether any new groups appear within the next
few days.  If any do, then it works.  If none do, then it doesn't
work.  I could write a function to make Gnus guess whether the server
supports @code{ask-server}, but it would just be a guess.  So I won't.
You could @code{telnet} to the server and say @code{HELP} and see
whether it lists @samp{NEWGROUPS} among the commands it understands.  If
it does, then it might work.  (But there are servers that lists
@samp{NEWGROUPS} without supporting the function properly.)

This variable can also be a list of select methods.  If so, Gnus will
issue an @code{ask-server} command to each of the select methods, and
subscribe them (or not) using the normal methods.  This might be handy
if you are monitoring a few servers for new groups.  A side effect is
that startup will take much longer, so you can meditate while waiting.
Use the mantra ``dingnusdingnusdingnus'' to achieve permanent bliss.


@node Subscription Methods
@subsection Subscription Methods

@vindex gnus-subscribe-newsgroup-method
What Gnus does when it encounters a new group is determined by the
@code{gnus-subscribe-newsgroup-method} variable.

This variable should contain a function.  This function will be called
with the name of the new group as the only parameter.

Some handy pre-fab functions are:

@table @code

@item gnus-subscribe-zombies
@vindex gnus-subscribe-zombies
Make all new groups zombies.  This is the default.  You can browse the
zombies later (with @kbd{A z}) and either kill them all off properly
(with @kbd{S z}), or subscribe to them (with @kbd{u}).

@item gnus-subscribe-randomly
@vindex gnus-subscribe-randomly
Subscribe all new groups in arbitrary order.  This really means that all
new groups will be added at ``the top'' of the group buffer.

@item gnus-subscribe-alphabetically
@vindex gnus-subscribe-alphabetically
Subscribe all new groups in alphabetical order.

@item gnus-subscribe-hierarchically
@vindex gnus-subscribe-hierarchically
Subscribe all new groups hierarchically.  The difference between this
function and @code{gnus-subscribe-alphabetically} is slight.
@code{gnus-subscribe-alphabetically} will subscribe new groups in a strictly
alphabetical fashion, while this function will enter groups into its
hierarchy.  So if you want to have the @samp{rec} hierarchy before the
@samp{comp} hierarchy, this function will not mess that configuration
up.  Or something like that.

@item gnus-subscribe-interactively
@vindex gnus-subscribe-interactively
Subscribe new groups interactively.  This means that Gnus will ask
you about @strong{all} new groups.  The groups you choose to subscribe
to will be subscribed hierarchically.

@item gnus-subscribe-killed
@vindex gnus-subscribe-killed
Kill all new groups.

@item gnus-subscribe-topics
@vindex gnus-subscribe-topics
Put the groups into the topic that has a matching @code{subscribe} topic 
parameter (@pxref{Topic Parameters}).  For instance, a @code{subscribe}
topic parameter that looks like

@example
"nnslashdot"
@end example

will mean that all groups that match that regex will be subscribed under 
that topic.

If no topics match the groups, the groups will be subscribed in the
top-level topic.

@end table

@vindex gnus-subscribe-hierarchical-interactive
A closely related variable is
@code{gnus-subscribe-hierarchical-interactive}.  (That's quite a
mouthful.)  If this variable is non-@code{nil}, Gnus will ask you in a
hierarchical fashion whether to subscribe to new groups or not.  Gnus
will ask you for each sub-hierarchy whether you want to descend the
hierarchy or not.

One common mistake is to set the variable a few paragraphs above
(@code{gnus-subscribe-newsgroup-method}) to
@code{gnus-subscribe-hierarchical-interactive}.  This is an error.  This
will not work.  This is ga-ga.  So don't do it.


@node Filtering New Groups
@subsection Filtering New Groups

A nice and portable way to control which new newsgroups should be
subscribed (or ignored) is to put an @dfn{options} line at the start of
the @file{.newsrc} file.  Here's an example:

@example
options -n !alt.all !rec.all sci.all
@end example

@vindex gnus-subscribe-options-newsgroup-method
This line obviously belongs to a serious-minded intellectual scientific
person (or she may just be plain old boring), because it says that all
groups that have names beginning with @samp{alt} and @samp{rec} should
be ignored, and all groups with names beginning with @samp{sci} should
be subscribed.  Gnus will not use the normal subscription method for
subscribing these groups.
@code{gnus-subscribe-options-newsgroup-method} is used instead.  This
variable defaults to @code{gnus-subscribe-alphabetically}.

@vindex gnus-options-not-subscribe
@vindex gnus-options-subscribe
If you don't want to mess with your @file{.newsrc} file, you can just
set the two variables @code{gnus-options-subscribe} and
@code{gnus-options-not-subscribe}.  These two variables do exactly the
same as the @file{.newsrc} @samp{options -n} trick.  Both are regexps,
and if the new group matches the former, it will be unconditionally
subscribed, and if it matches the latter, it will be ignored.

@vindex gnus-auto-subscribed-groups
Yet another variable that meddles here is
@code{gnus-auto-subscribed-groups}.  It works exactly like
@code{gnus-options-subscribe}, and is therefore really superfluous, but I
thought it would be nice to have two of these.  This variable is more
meant for setting some ground rules, while the other variable is used
more for user fiddling.  By default this variable makes all new groups
that come from mail backends (@code{nnml}, @code{nnbabyl},
@code{nnfolder}, @code{nnmbox}, and @code{nnmh}) subscribed.  If you
don't like that, just set this variable to @code{nil}.

New groups that match this regexp are subscribed using
@code{gnus-subscribe-options-newsgroup-method}.


@node Changing Servers
@section Changing Servers
@cindex changing servers

Sometimes it is necessary to move from one @sc{nntp} server to another.
This happens very rarely, but perhaps you change jobs, or one server is
very flaky and you want to use another.

Changing the server is pretty easy, right?  You just change
@code{gnus-select-method} to point to the new server?

@emph{Wrong!}

Article numbers are not (in any way) kept synchronized between different
@sc{nntp} servers, and the only way Gnus keeps track of what articles
you have read is by keeping track of article numbers.  So when you
change @code{gnus-select-method}, your @file{.newsrc} file becomes
worthless.

Gnus provides a few functions to attempt to translate a @file{.newsrc}
file from one server to another.  They all have one thing in
common---they take a looong time to run.  You don't want to use these
functions more than absolutely necessary.

@kindex M-x gnus-change-server
@findex gnus-change-server
If you have access to both servers, Gnus can request the headers for all
the articles you have read and compare @code{Message-ID}s and map the
article numbers of the read articles and article marks.  The @kbd{M-x
gnus-change-server} command will do this for all your native groups.  It
will prompt for the method you want to move to.

@kindex M-x gnus-group-move-group-to-server
@findex gnus-group-move-group-to-server
You can also move individual groups with the @kbd{M-x
gnus-group-move-group-to-server} command.  This is useful if you want to
move a (foreign) group from one server to another.

@kindex M-x gnus-group-clear-data-on-native-groups
@findex gnus-group-clear-data-on-native-groups
If you don't have access to both the old and new server, all your marks
and read ranges have become worthless.  You can use the @kbd{M-x
gnus-group-clear-data-on-native-groups} command to clear out all data
that you have on your native groups.  Use with caution.

After changing servers, you @strong{must} move the cache hierarchy away,
since the cached articles will have wrong article numbers, which will
affect which articles Gnus thinks are read.


@node Startup Files
@section Startup Files
@cindex startup files
@cindex .newsrc
@cindex .newsrc.el
@cindex .newsrc.eld

Now, you all know about the @file{.newsrc} file.  All subscription
information is traditionally stored in this file.

Things got a bit more complicated with @sc{gnus}.  In addition to
keeping the @file{.newsrc} file updated, it also used a file called
@file{.newsrc.el} for storing all the information that didn't fit into
the @file{.newsrc} file.  (Actually, it also duplicated everything in
the @file{.newsrc} file.)  @sc{gnus} would read whichever one of these
files was the most recently saved, which enabled people to swap between
@sc{gnus} and other newsreaders.

That was kinda silly, so Gnus went one better: In addition to the
@file{.newsrc} and @file{.newsrc.el} files, Gnus also has a file called
@file{.newsrc.eld}.  It will read whichever of these files that are most
recent, but it will never write a @file{.newsrc.el} file.  You should
never delete the @file{.newsrc.eld} file---it contains much information
not stored in the @file{.newsrc} file.

@vindex gnus-save-newsrc-file
@vindex gnus-read-newsrc-file
You can turn off writing the @file{.newsrc} file by setting
@code{gnus-save-newsrc-file} to @code{nil}, which means you can delete
the file and save some space, as well as exiting from Gnus faster.
However, this will make it impossible to use other newsreaders than
Gnus.  But hey, who would want to, right?  Similarly, setting
@code{gnus-read-newsrc-file} to @code{nil} makes Gnus ignore the
@file{.newsrc} file and any @file{.newsrc-SERVER} files, which is
convenient if you have a tendency to use Netscape once in a while.

@vindex gnus-save-killed-list
If @code{gnus-save-killed-list} (default @code{t}) is @code{nil}, Gnus
will not save the list of killed groups to the startup file.  This will
save both time (when starting and quitting) and space (on disk).  It
will also mean that Gnus has no record of what groups are new or old,
so the automatic new groups subscription methods become meaningless.
You should always set @code{gnus-check-new-newsgroups} to @code{nil} or
@code{ask-server} if you set this variable to @code{nil} (@pxref{New
Groups}).  This variable can also be a regular expression.  If that's
the case, remove all groups that do not match this regexp before
saving.  This can be useful in certain obscure situations that involve
several servers where not all servers support @code{ask-server}.

@vindex gnus-startup-file
The @code{gnus-startup-file} variable says where the startup files are.
The default value is @file{~/.newsrc}, with the Gnus (El Dingo) startup
file being whatever that one is, with a @samp{.eld} appended.

@vindex gnus-save-newsrc-hook
@vindex gnus-save-quick-newsrc-hook
@vindex gnus-save-standard-newsrc-hook
@code{gnus-save-newsrc-hook} is called before saving any of the newsrc
files, while @code{gnus-save-quick-newsrc-hook} is called just before
saving the @file{.newsrc.eld} file, and
@code{gnus-save-standard-newsrc-hook} is called just before saving the
@file{.newsrc} file.  The latter two are commonly used to turn version
control on or off.  Version control is on by default when saving the
startup files.  If you want to turn backup creation off, say something like:

@lisp
(defun turn-off-backup ()
  (set (make-local-variable 'backup-inhibited) t))

(add-hook 'gnus-save-quick-newsrc-hook 'turn-off-backup)
(add-hook 'gnus-save-standard-newsrc-hook 'turn-off-backup)
@end lisp

@vindex gnus-init-file
When Gnus starts, it will read the @code{gnus-site-init-file}
(@file{.../site-lisp/gnus} by default) and @code{gnus-init-file}
(@file{~/.gnus} by default) files.  These are normal Emacs Lisp files
and can be used to avoid cluttering your @file{~/.emacs} and
@file{site-init} files with Gnus stuff.  Gnus will also check for files
with the same names as these, but with @file{.elc} and @file{.el}
suffixes.  In other words, if you have set @code{gnus-init-file} to
@file{~/.gnus}, it will look for @file{~/.gnus.elc}, @file{~/.gnus.el},
and finally @file{~/.gnus} (in this order).



@node Auto Save
@section Auto Save
@cindex dribble file
@cindex auto-save

Whenever you do something that changes the Gnus data (reading articles,
catching up, killing/subscribing groups), the change is added to a
special @dfn{dribble buffer}.  This buffer is auto-saved the normal
Emacs way.  If your Emacs should crash before you have saved the
@file{.newsrc} files, all changes you have made can be recovered from
this file.

If Gnus detects this file at startup, it will ask the user whether to
read it.  The auto save file is deleted whenever the real startup file is
saved.

@vindex gnus-use-dribble-file
If @code{gnus-use-dribble-file} is @code{nil}, Gnus won't create and
maintain a dribble buffer.  The default is @code{t}.

@vindex gnus-dribble-directory
Gnus will put the dribble file(s) in @code{gnus-dribble-directory}.  If
this variable is @code{nil}, which it is by default, Gnus will dribble
into the directory where the @file{.newsrc} file is located.  (This is
normally the user's home directory.)  The dribble file will get the same
file permissions as the @code{.newsrc} file.

@vindex gnus-always-read-dribble-file
If @code{gnus-always-read-dribble-file} is non-@code{nil}, Gnus will
read the dribble file on startup without querying the user.


@node The Active File
@section The Active File
@cindex active file
@cindex ignored groups

When Gnus starts, or indeed whenever it tries to determine whether new
articles have arrived, it reads the active file.  This is a very large
file that lists all the active groups and articles on the server.

@vindex gnus-ignored-newsgroups
Before examining the active file, Gnus deletes all lines that match the
regexp @code{gnus-ignored-newsgroups}.  This is done primarily to reject
any groups with bogus names, but you can use this variable to make Gnus
ignore hierarchies you aren't ever interested in.  However, this is not
recommended.  In fact, it's highly discouraged.  Instead, @pxref{New
Groups} for an overview of other variables that can be used instead.

@c This variable is
@c @code{nil} by default, and will slow down active file handling somewhat
@c if you set it to anything else.

@vindex gnus-read-active-file
@c @head
The active file can be rather Huge, so if you have a slow network, you
can set @code{gnus-read-active-file} to @code{nil} to prevent Gnus from
reading the active file.  This variable is @code{some} by default.

Gnus will try to make do by getting information just on the groups that
you actually subscribe to.

Note that if you subscribe to lots and lots of groups, setting this
variable to @code{nil} will probably make Gnus slower, not faster.  At
present, having this variable @code{nil} will slow Gnus down
considerably, unless you read news over a 2400 baud modem.

This variable can also have the value @code{some}.  Gnus will then
attempt to read active info only on the subscribed groups.  On some
servers this is quite fast (on sparkling, brand new INN servers that
support the @code{LIST ACTIVE group} command), on others this isn't fast
at all.  In any case, @code{some} should be faster than @code{nil}, and
is certainly faster than @code{t} over slow lines.

Some news servers (Leafnode and old versions of INN, for instance) do
not support the @code{LIST ACTIVE group}.  For these servers, @code{nil}
is probably the most efficient value for this variable.

If this variable is @code{nil}, Gnus will ask for group info in total
lock-step, which isn't very fast.  If it is @code{some} and you use an
@sc{nntp} server, Gnus will pump out commands as fast as it can, and
read all the replies in one swoop.  This will normally result in better
performance, but if the server does not support the aforementioned
@code{LIST ACTIVE group} command, this isn't very nice to the server.

If you think that starting up Gnus takes too long, try all the three
different values for this variable and see what works best for you. 

In any case, if you use @code{some} or @code{nil}, you should definitely
kill all groups that you aren't interested in to speed things up.

Note that this variable also affects active file retrieval from
secondary select methods.


@node Startup Variables
@section Startup Variables

@table @code

@item gnus-load-hook
@vindex gnus-load-hook
A hook run while Gnus is being loaded.  Note that this hook will
normally be run just once in each Emacs session, no matter how many
times you start Gnus.

@item gnus-before-startup-hook
@vindex gnus-before-startup-hook
A hook run after starting up Gnus successfully.

@item gnus-startup-hook
@vindex gnus-startup-hook
A hook run as the very last thing after starting up Gnus

@item gnus-started-hook
@vindex gnus-started-hook
A hook that is run as the very last thing after starting up Gnus
successfully.

@item gnus-setup-news-hook
@vindex gnus-setup-news-hook
A hook that is run after reading the @file{.newsrc} file(s), but before
generating the group buffer.

@item gnus-check-bogus-newsgroups
@vindex gnus-check-bogus-newsgroups
If non-@code{nil}, Gnus will check for and delete all bogus groups at
startup.  A @dfn{bogus group} is a group that you have in your
@file{.newsrc} file, but doesn't exist on the news server.  Checking for
bogus groups can take quite a while, so to save time and resources it's
best to leave this option off, and do the checking for bogus groups once
in a while from the group buffer instead (@pxref{Group Maintenance}).

@item gnus-inhibit-startup-message
@vindex gnus-inhibit-startup-message
If non-@code{nil}, the startup message won't be displayed.  That way,
your boss might not notice as easily that you are reading news instead
of doing your job.  Note that this variable is used before
@file{.gnus.el} is loaded, so it should be set in @code{.emacs} instead.

@item gnus-no-groups-message
@vindex gnus-no-groups-message
Message displayed by Gnus when no groups are available.

@item gnus-play-startup-jingle
@vindex gnus-play-startup-jingle
If non-@code{nil}, play the Gnus jingle at startup.

@item gnus-startup-jingle
@vindex gnus-startup-jingle
Jingle to be played if the above variable is non-@code{nil}.  The
default is @samp{Tuxedomoon.Jingle4.au}.

@end table


@node The Group Buffer
@chapter The Group Buffer
@cindex group buffer

The @dfn{group buffer} lists all (or parts) of the available groups.  It
is the first buffer shown when Gnus starts, and will never be killed as
long as Gnus is active.

@iftex
@iflatex
\gnusfigure{The Group Buffer}{320}{
\put(75,50){\epsfig{figure=tmp/group.ps,height=9cm}}
\put(120,37){\makebox(0,0)[t]{Buffer name}}
\put(120,38){\vector(1,2){10}}
\put(40,60){\makebox(0,0)[r]{Mode line}}
\put(40,58){\vector(1,0){30}}
\put(200,28){\makebox(0,0)[t]{Native select method}}
\put(200,26){\vector(-1,2){15}}
}
@end iflatex
@end iftex

@menu
* Group Buffer Format::    Information listed and how you can change it.
* Group Maneuvering::      Commands for moving in the group buffer.
* Selecting a Group::      Actually reading news.
* Group Data::             Changing the info for a group.
* Subscription Commands::  Unsubscribing, killing, subscribing.
* Group Levels::           Levels? What are those, then?
* Group Score::            A mechanism for finding out what groups you like.
* Marking Groups::         You can mark groups for later processing.
* Foreign Groups::         Creating and editing groups.
* Group Parameters::       Each group may have different parameters set.
* Listing Groups::         Gnus can list various subsets of the groups.
* Sorting Groups::         Re-arrange the group order.
* Group Maintenance::      Maintaining a tidy @file{.newsrc} file.
* Browse Foreign Server::  You can browse a server.  See what it has to offer.
* Exiting Gnus::           Stop reading news and get some work done.
* Group Topics::           A folding group mode divided into topics.
* Misc Group Stuff::       Other stuff that you can to do.
@end menu


@node Group Buffer Format
@section Group Buffer Format

@menu
* Group Line Specification::       Deciding how the group buffer is to look.
* Group Modeline Specification::   The group buffer modeline.
* Group Highlighting::             Having nice colors in the group buffer.
@end menu


@node Group Line Specification
@subsection Group Line Specification
@cindex group buffer format

The default format of the group buffer is nice and dull, but you can
make it as exciting and ugly as you feel like.

Here's a couple of example group lines:

@example
     25: news.announce.newusers
 *    0: alt.fan.andrea-dworkin
@end example

Quite simple, huh?

You can see that there are 25 unread articles in
@samp{news.announce.newusers}.  There are no unread articles, but some
ticked articles, in @samp{alt.fan.andrea-dworkin} (see that little
asterisk at the beginning of the line?).

@vindex gnus-group-line-format
You can change that format to whatever you want by fiddling with the
@code{gnus-group-line-format} variable.  This variable works along the
lines of a @code{format} specification, which is pretty much the same as
a @code{printf} specifications, for those of you who use (feh!) C.
@xref{Formatting Variables}.

@samp{%M%S%5y: %(%g%)\n} is the value that produced those lines above.

There should always be a colon on the line; the cursor always moves to
the colon after performing an operation.  Nothing else is required---not
even the group name.  All displayed text is just window dressing, and is
never examined by Gnus.  Gnus stores all real information it needs using
text properties.

(Note that if you make a really strange, wonderful, spreadsheet-like
layout, everybody will believe you are hard at work with the accounting
instead of wasting time reading news.)

Here's a list of all available format characters:

@table @samp

@item M
An asterisk if the group only has marked articles.

@item S
Whether the group is subscribed.

@item L
Level of subscribedness.

@item N
Number of unread articles.

@item I
Number of dormant articles.

@item T
Number of ticked articles.

@item R
Number of read articles.

@item t
Estimated total number of articles.  (This is really @var{max-number}
minus @var{min-number} plus 1.)

@item y
Number of unread, unticked, non-dormant articles.

@item i
Number of ticked and dormant articles.

@item g
Full group name.

@item G
Group name.

@item D
Newsgroup description.

@item o
@samp{m} if moderated.

@item O
@samp{(m)} if moderated.

@item s
Select method.

@item n
Select from where.

@item z
A string that looks like @samp{<%s:%n>} if a foreign select method is
used.

@item P
Indentation based on the level of the topic (@pxref{Group Topics}).

@item c
@vindex gnus-group-uncollapsed-levels
Short (collapsed) group name.  The @code{gnus-group-uncollapsed-levels}
variable says how many levels to leave at the end of the group name.
The default is 1---this will mean that group names like
@samp{gnu.emacs.gnus} will be shortened to @samp{g.e.gnus}.

@item m
@vindex gnus-new-mail-mark
@cindex %
@samp{%} (@code{gnus-new-mail-mark}) if there has arrived new mail to
the group lately.

@item d
A string that says when you last read the group (@pxref{Group
Timestamp}).

@item u
User defined specifier.  The next character in the format string should
be a letter.  Gnus will call the function
@code{gnus-user-format-function-}@samp{X}, where @samp{X} is the letter
following @samp{%u}.  The function will be passed a single dummy
parameter as argument.  The function should return a string, which will
be inserted into the buffer just like information from any other
specifier.
@end table

@cindex *
All the ``number-of'' specs will be filled with an asterisk (@samp{*})
if no info is available---for instance, if it is a non-activated foreign
group, or a bogus native group.


@node Group Modeline Specification
@subsection Group Modeline Specification
@cindex group modeline

@vindex gnus-group-mode-line-format
The mode line can be changed by setting
@code{gnus-group-mode-line-format} (@pxref{Mode Line Formatting}).  It
doesn't understand that many format specifiers:

@table @samp
@item S
The native news server.
@item M
The native select method.
@end table


@node Group Highlighting
@subsection Group Highlighting
@cindex highlighting
@cindex group highlighting

@vindex gnus-group-highlight
Highlighting in the group buffer is controlled by the
@code{gnus-group-highlight} variable.  This is an alist with elements
that look like @code{(@var{form} . @var{face})}.  If @var{form} evaluates to
something non-@code{nil}, the @var{face} will be used on the line.

Here's an example value for this variable that might look nice if the
background is dark:

@lisp
(cond (window-system
       (setq custom-background-mode 'light)
       (defface my-group-face-1
         '((t (:foreground "Red" :bold t))) "First group face")
       (defface my-group-face-2
         '((t (:foreground "DarkSeaGreen4" :bold t))) "Second group face")
       (defface my-group-face-3
         '((t (:foreground "Green4" :bold t))) "Third group face")
       (defface my-group-face-4
         '((t (:foreground "SteelBlue" :bold t))) "Fourth group face")
       (defface my-group-face-5
         '((t (:foreground "Blue" :bold t))) "Fifth group face")))

(setq gnus-group-highlight
      '(((> unread 200) . my-group-face-1)
        ((and (< level 3) (zerop unread)) . my-group-face-2)
        ((< level 3) . my-group-face-3)
        ((zerop unread) . my-group-face-4)
        (t . my-group-face-5)))
@end lisp

Also @pxref{Faces and Fonts}.

Variables that are dynamically bound when the forms are evaluated
include:

@table @code
@item group
The group name.
@item unread
The number of unread articles in the group.
@item method
The select method.
@item mailp
Whether the group is a mail group.
@item level
The level of the group.
@item score
The score of the group.
@item ticked
The number of ticked articles in the group.
@item total
The total number of articles in the group.  Or rather, MAX-NUMBER minus
MIN-NUMBER plus one.
@item topic
When using the topic minor mode, this variable is bound to the current
topic being inserted.
@end table

When the forms are @code{eval}ed, point is at the beginning of the line
of the group in question, so you can use many of the normal Gnus
functions for snarfing info on the group.

@vindex gnus-group-update-hook
@findex gnus-group-highlight-line
@code{gnus-group-update-hook} is called when a group line is changed.
It will not be called when @code{gnus-visual} is @code{nil}.  This hook
calls @code{gnus-group-highlight-line} by default.


@node Group Maneuvering
@section Group Maneuvering
@cindex group movement

All movement commands understand the numeric prefix and will behave as
expected, hopefully.

@table @kbd

@item n
@kindex n (Group)
@findex gnus-group-next-unread-group
Go to the next group that has unread articles
(@code{gnus-group-next-unread-group}).

@item p
@itemx DEL
@kindex DEL (Group)
@kindex p (Group)
@findex gnus-group-prev-unread-group
Go to the previous group that has unread articles
(@code{gnus-group-prev-unread-group}).

@item N
@kindex N (Group)
@findex gnus-group-next-group
Go to the next group (@code{gnus-group-next-group}).

@item P
@kindex P (Group)
@findex gnus-group-prev-group
Go to the previous group (@code{gnus-group-prev-group}).

@item M-n
@kindex M-n (Group)
@findex gnus-group-next-unread-group-same-level
Go to the next unread group on the same (or lower) level
(@code{gnus-group-next-unread-group-same-level}).

@item M-p
@kindex M-p (Group)
@findex gnus-group-prev-unread-group-same-level
Go to the previous unread group on the same (or lower) level
(@code{gnus-group-prev-unread-group-same-level}).
@end table

Three commands for jumping to groups:

@table @kbd

@item j
@kindex j (Group)
@findex gnus-group-jump-to-group
Jump to a group (and make it visible if it isn't already)
(@code{gnus-group-jump-to-group}).  Killed groups can be jumped to, just
like living groups.

@item ,
@kindex , (Group)
@findex gnus-group-best-unread-group
Jump to the unread group with the lowest level
(@code{gnus-group-best-unread-group}).

@item .
@kindex . (Group)
@findex gnus-group-first-unread-group
Jump to the first group with unread articles
(@code{gnus-group-first-unread-group}).
@end table

@vindex gnus-group-goto-unread
If @code{gnus-group-goto-unread} is @code{nil}, all the movement
commands will move to the next group, not the next unread group.  Even
the commands that say they move to the next unread group.  The default
is @code{t}.


@node Selecting a Group
@section Selecting a Group
@cindex group selection

@table @kbd

@item SPACE
@kindex SPACE (Group)
@findex gnus-group-read-group
Select the current group, switch to the summary buffer and display the
first unread article (@code{gnus-group-read-group}).  If there are no
unread articles in the group, or if you give a non-numerical prefix to
this command, Gnus will offer to fetch all the old articles in this
group from the server.  If you give a numerical prefix @var{N}, @var{N}
determines the number of articles Gnus will fetch.  If @var{N} is
positive, Gnus fetches the @var{N} newest articles, if @var{N} is
negative, Gnus fetches the @code{abs(@var{N})} oldest articles.

@item RET
@kindex RET (Group)
@findex gnus-group-select-group
Select the current group and switch to the summary buffer
(@code{gnus-group-select-group}).  Takes the same arguments as
@code{gnus-group-read-group}---the only difference is that this command
does not display the first unread article automatically upon group
entry.

@item M-RET
@kindex M-RET (Group)
@findex gnus-group-quick-select-group
This does the same as the command above, but tries to do it with the
minimum amount of fuzz (@code{gnus-group-quick-select-group}).  No
scoring/killing will be performed, there will be no highlights and no
expunging.  This might be useful if you're in a real hurry and have to
enter some humongous group.  If you give a 0 prefix to this command
(i.e., @kbd{0 M-RET}), Gnus won't even generate the summary buffer,
which is useful if you want to toggle threading before generating the
summary buffer (@pxref{Summary Generation Commands}).

@item M-SPACE
@kindex M-SPACE (Group)
@findex gnus-group-visible-select-group
This is yet one more command that does the same as the @kbd{RET}
command, but this one does it without expunging and hiding dormants
(@code{gnus-group-visible-select-group}).

@item M-C-RET
@kindex M-C-RET (Group)
@findex gnus-group-select-group-ephemerally
Finally, this command selects the current group ephemerally without
doing any processing of its contents
(@code{gnus-group-select-group-ephemerally}).  Even threading has been
turned off.  Everything you do in the group after selecting it in this
manner will have no permanent effects.

@end table

@vindex gnus-large-newsgroup
The @code{gnus-large-newsgroup} variable says what Gnus should consider
to be a big group.  This is 200 by default.  If the group has more
(unread and/or ticked) articles than this, Gnus will query the user
before entering the group.  The user can then specify how many articles
should be fetched from the server.  If the user specifies a negative
number (@code{-n}), the @code{n} oldest articles will be fetched.  If it
is positive, the @code{n} articles that have arrived most recently will
be fetched.

@vindex gnus-select-group-hook
@vindex gnus-auto-select-first
@code{gnus-auto-select-first} control whether any articles are selected
automatically when entering a group with the @kbd{SPACE} command.

@table @code

@item nil
Don't select any articles when entering the group.  Just display the
full summary buffer.

@item t
Select the first unread article when entering the group.

@item best
Select the highest scored article in the group when entering the
group.

@end table

This variable can also be a function.  In that case, that function will
be called to place point on a subject line, and/or select some article.
Useful functions include:

@table @code
@item gnus-summary-first-unread-subject
Place point on the subject line of the first unread article, but
don't select the article.

@item gnus-summary-first-unread-article
Select the first unread article.

@item gnus-summary-best-unread-article
Select the highest-scored unread article.
@end table


If you want to prevent automatic selection in some group (say, in a
binary group with Huge articles) you can set this variable to @code{nil}
in @code{gnus-select-group-hook}, which is called when a group is
selected.


@node Subscription Commands
@section Subscription Commands
@cindex subscription

@table @kbd

@item S t
@itemx u
@kindex S t (Group)
@kindex u (Group)
@findex gnus-group-unsubscribe-current-group
@c @icon{gnus-group-unsubscribe}
Toggle subscription to the current group
(@code{gnus-group-unsubscribe-current-group}).

@item S s
@itemx U
@kindex S s (Group)
@kindex U (Group)
@findex gnus-group-unsubscribe-group
Prompt for a group to subscribe, and then subscribe it.  If it was
subscribed already, unsubscribe it instead
(@code{gnus-group-unsubscribe-group}).

@item S k
@itemx C-k
@kindex S k (Group)
@kindex C-k (Group)
@findex gnus-group-kill-group
@c @icon{gnus-group-kill-group}
Kill the current group (@code{gnus-group-kill-group}).

@item S y
@itemx C-y
@kindex S y (Group)
@kindex C-y (Group)
@findex gnus-group-yank-group
Yank the last killed group (@code{gnus-group-yank-group}).

@item C-x C-t
@kindex C-x C-t (Group)
@findex gnus-group-transpose-groups
Transpose two groups (@code{gnus-group-transpose-groups}).  This isn't
really a subscription command, but you can use it instead of a
kill-and-yank sequence sometimes.

@item S w
@itemx C-w
@kindex S w (Group)
@kindex C-w (Group)
@findex gnus-group-kill-region
Kill all groups in the region (@code{gnus-group-kill-region}).

@item S z
@kindex S z (Group)
@findex gnus-group-kill-all-zombies
Kill all zombie groups (@code{gnus-group-kill-all-zombies}).

@item S C-k
@kindex S C-k (Group)
@findex gnus-group-kill-level
Kill all groups on a certain level (@code{gnus-group-kill-level}).
These groups can't be yanked back after killing, so this command should
be used with some caution.  The only time where this command comes in
really handy is when you have a @file{.newsrc} with lots of unsubscribed
groups that you want to get rid off.  @kbd{S C-k} on level 7 will
kill off all unsubscribed groups that do not have message numbers in the
@file{.newsrc} file.

@end table

Also @pxref{Group Levels}.


@node Group Data
@section Group Data

@table @kbd

@item c
@kindex c (Group)
@findex gnus-group-catchup-current
@vindex gnus-group-catchup-group-hook
@c @icon{gnus-group-catchup-current}
Mark all unticked articles in this group as read
(@code{gnus-group-catchup-current}).
@code{gnus-group-catchup-group-hook} is called when catching up a group from
the group buffer.

@item C
@kindex C (Group)
@findex gnus-group-catchup-current-all
Mark all articles in this group, even the ticked ones, as read
(@code{gnus-group-catchup-current-all}).

@item M-c
@kindex M-c (Group)
@findex gnus-group-clear-data
Clear the data from the current group---nix out marks and the list of
read articles (@code{gnus-group-clear-data}).

@item M-x gnus-group-clear-data-on-native-groups
@kindex M-x gnus-group-clear-data-on-native-groups
@findex gnus-group-clear-data-on-native-groups
If you have switched from one @sc{nntp} server to another, all your marks
and read ranges have become worthless.  You can use this command to
clear out all data that you have on your native groups.  Use with
caution.

@end table


@node Group Levels
@section Group Levels
@cindex group level
@cindex level

All groups have a level of @dfn{subscribedness}.  For instance, if a
group is on level 2, it is more subscribed than a group on level 5.  You
can ask Gnus to just list groups on a given level or lower
(@pxref{Listing Groups}), or to just check for new articles in groups on
a given level or lower (@pxref{Scanning New Messages}).

Remember:  The higher the level of the group, the less important it is.

@table @kbd

@item S l
@kindex S l (Group)
@findex gnus-group-set-current-level
Set the level of the current group.  If a numeric prefix is given, the
next @var{n} groups will have their levels set.  The user will be
prompted for a level.
@end table

@vindex gnus-level-killed
@vindex gnus-level-zombie
@vindex gnus-level-unsubscribed
@vindex gnus-level-subscribed
Gnus considers groups from levels 1 to
@code{gnus-level-subscribed} (inclusive) (default 5) to be subscribed,
@code{gnus-level-subscribed} (exclusive) and
@code{gnus-level-unsubscribed} (inclusive) (default 7) to be
unsubscribed, @code{gnus-level-zombie} to be zombies (walking dead)
(default 8) and @code{gnus-level-killed} to be killed (completely dead)
(default 9).  Gnus treats subscribed and unsubscribed groups exactly the
same, but zombie and killed groups have no information on what articles
you have read, etc, stored.  This distinction between dead and living
groups isn't done because it is nice or clever, it is done purely for
reasons of efficiency.

It is recommended that you keep all your mail groups (if any) on quite
low levels (e.g. 1 or 2).

Maybe the following description of the default behavior of Gnus helps to
understand what these levels are all about.  By default, Gnus shows you
subscribed nonempty groups, but by hitting @kbd{L} you can have it show
empty subscribed groups and unsubscribed groups, too.  Type @kbd{l} to
go back to showing nonempty subscribed groups again.  Thus, unsubscribed
groups are hidden, in a way.

Zombie and killed groups are similar to unsubscribed groups in that they
are hidden by default.  But they are different from subscribed and
unsubscribed groups in that Gnus doesn't ask the news server for
information (number of messages, number of unread messages) on zombie
and killed groups.  Normally, you use @kbd{C-k} to kill the groups you
aren't interested in.  If most groups are killed, Gnus is faster.

Why does Gnus distinguish between zombie and killed groups?  Well, when
a new group arrives on the server, Gnus by default makes it a zombie
group.  This means that you are normally not bothered with new groups,
but you can type @kbd{A z} to get a list of all new groups.  Subscribe
the ones you like and kill the ones you don't want.  (@kbd{A k} shows a
list of killed groups.)

If you want to play with the level variables, you should show some care.
Set them once, and don't touch them ever again.  Better yet, don't touch
them at all unless you know exactly what you're doing.

@vindex gnus-level-default-unsubscribed
@vindex gnus-level-default-subscribed
Two closely related variables are @code{gnus-level-default-subscribed}
(default 3) and @code{gnus-level-default-unsubscribed} (default 6),
which are the levels that new groups will be put on if they are
(un)subscribed.  These two variables should, of course, be inside the
relevant valid ranges.

@vindex gnus-keep-same-level
If @code{gnus-keep-same-level} is non-@code{nil}, some movement commands
will only move to groups of the same level (or lower).  In
particular, going from the last article in one group to the next group
will go to the next group of the same level (or lower).  This might be
handy if you want to read the most important groups before you read the
rest.

If this variable is @code{best}, Gnus will make the next newsgroup the
one with the best level.

@vindex gnus-group-default-list-level
All groups with a level less than or equal to
@code{gnus-group-default-list-level} will be listed in the group buffer
by default.

@vindex gnus-group-list-inactive-groups
If @code{gnus-group-list-inactive-groups} is non-@code{nil}, non-active
groups will be listed along with the unread groups.  This variable is
@code{t} by default.  If it is @code{nil}, inactive groups won't be
listed.

@vindex gnus-group-use-permanent-levels
If @code{gnus-group-use-permanent-levels} is non-@code{nil}, once you
give a level prefix to @kbd{g} or @kbd{l}, all subsequent commands will
use this level as the ``work'' level.

@vindex gnus-activate-level
Gnus will normally just activate (i. e., query the server about) groups
on level @code{gnus-activate-level} or less.  If you don't want to
activate unsubscribed groups, for instance, you might set this variable
to 5.  The default is 6.


@node Group Score
@section Group Score
@cindex group score
@cindex group rank
@cindex rank

You would normally keep important groups on high levels, but that scheme
is somewhat restrictive.  Don't you wish you could have Gnus sort the
group buffer according to how often you read groups, perhaps?  Within
reason?

This is what @dfn{group score} is for.  You can have Gnus assign a score
to each group through the mechanism described below.  You can then sort
the group buffer based on this score.  Alternatively, you can sort on
score and then level.  (Taken together, the level and the score is
called the @dfn{rank} of the group.  A group that is on level 4 and has
a score of 1 has a higher rank than a group on level 5 that has a score
of 300.  (The level is the most significant part and the score is the
least significant part.))

@findex gnus-summary-bubble-group
If you want groups you read often to get higher scores than groups you
read seldom you can add the @code{gnus-summary-bubble-group} function to
the @code{gnus-summary-exit-hook} hook.  This will result (after
sorting) in a bubbling sort of action.  If you want to see that in
action after each summary exit, you can add
@code{gnus-group-sort-groups-by-rank} or
@code{gnus-group-sort-groups-by-score} to the same hook, but that will
slow things down somewhat.


@node Marking Groups
@section Marking Groups
@cindex marking groups

If you want to perform some command on several groups, and they appear
subsequently in the group buffer, you would normally just give a
numerical prefix to the command.  Most group commands will then do your
bidding on those groups.

However, if the groups are not in sequential order, you can still
perform a command on several groups.  You simply mark the groups first
with the process mark and then execute the command.

@table @kbd

@item #
@kindex # (Group)
@itemx M m
@kindex M m (Group)
@findex gnus-group-mark-group
Set the mark on the current group (@code{gnus-group-mark-group}).

@item M-#
@kindex M-# (Group)
@itemx M u
@kindex M u (Group)
@findex gnus-group-unmark-group
Remove the mark from the current group
(@code{gnus-group-unmark-group}).

@item M U
@kindex M U (Group)
@findex gnus-group-unmark-all-groups
Remove the mark from all groups (@code{gnus-group-unmark-all-groups}).

@item M w
@kindex M w (Group)
@findex gnus-group-mark-region
Mark all groups between point and mark (@code{gnus-group-mark-region}).

@item M b
@kindex M b (Group)
@findex gnus-group-mark-buffer
Mark all groups in the buffer (@code{gnus-group-mark-buffer}).

@item M r
@kindex M r (Group)
@findex gnus-group-mark-regexp
Mark all groups that match some regular expression
(@code{gnus-group-mark-regexp}).
@end table

Also @pxref{Process/Prefix}.

@findex gnus-group-universal-argument
If you want to execute some command on all groups that have been marked
with the process mark, you can use the @kbd{M-&}
(@code{gnus-group-universal-argument}) command.  It will prompt you for
the command to be executed.


@node Foreign Groups
@section Foreign Groups
@cindex foreign groups

Below are some group mode commands for making and editing general foreign
groups, as well as commands to ease the creation of a few
special-purpose groups.  All these commands insert the newly created
groups under point---@code{gnus-subscribe-newsgroup-method} is not
consulted.

@table @kbd

@item G m
@kindex G m (Group)
@findex gnus-group-make-group
@cindex making groups
Make a new group (@code{gnus-group-make-group}).  Gnus will prompt you
for a name, a method and possibly an @dfn{address}.  For an easier way
to subscribe to @sc{nntp} groups, @pxref{Browse Foreign Server}.

@item G r
@kindex G r (Group)
@findex gnus-group-rename-group
@cindex renaming groups
Rename the current group to something else
(@code{gnus-group-rename-group}).  This is valid only on some
groups---mail groups mostly.  This command might very well be quite slow
on some backends.

@item G c
@kindex G c (Group)
@cindex customizing
@findex gnus-group-customize
Customize the group parameters (@code{gnus-group-customize}).

@item G e
@kindex G e (Group)
@findex gnus-group-edit-group-method
@cindex renaming groups
Enter a buffer where you can edit the select method of the current
group (@code{gnus-group-edit-group-method}).

@item G p
@kindex G p (Group)
@findex gnus-group-edit-group-parameters
Enter a buffer where you can edit the group parameters
(@code{gnus-group-edit-group-parameters}).

@item G E
@kindex G E (Group)
@findex gnus-group-edit-group
Enter a buffer where you can edit the group info
(@code{gnus-group-edit-group}).

@item G d
@kindex G d (Group)
@findex gnus-group-make-directory-group
@cindex nndir
Make a directory group (@pxref{Directory Groups}).  You will be prompted
for a directory name (@code{gnus-group-make-directory-group}).

@item G h
@kindex G h (Group)
@cindex help group
@findex gnus-group-make-help-group
Make the Gnus help group (@code{gnus-group-make-help-group}).

@item G a
@kindex G a (Group)
@cindex (ding) archive
@cindex archive group
@findex gnus-group-make-archive-group
@vindex gnus-group-archive-directory
@vindex gnus-group-recent-archive-directory
Make a Gnus archive group (@code{gnus-group-make-archive-group}).  By
default a group pointing to the most recent articles will be created
(@code{gnus-group-recent-archive-directory}), but given a prefix, a full
group will be created from @code{gnus-group-archive-directory}.

@item G k
@kindex G k (Group)
@findex gnus-group-make-kiboze-group
@cindex nnkiboze
Make a kiboze group.  You will be prompted for a name, for a regexp to
match groups to be ``included'' in the kiboze group, and a series of
strings to match on headers (@code{gnus-group-make-kiboze-group}).
@xref{Kibozed Groups}.

@item G D
@kindex G D (Group)
@findex gnus-group-enter-directory
@cindex nneething
Read an arbitrary directory as if it were a newsgroup with the
@code{nneething} backend (@code{gnus-group-enter-directory}).
@xref{Anything Groups}.

@item G f
@kindex G f (Group)
@findex gnus-group-make-doc-group
@cindex ClariNet Briefs
@cindex nndoc
Make a group based on some file or other
(@code{gnus-group-make-doc-group}).  If you give a prefix to this
command, you will be prompted for a file name and a file type.
Currently supported types are @code{babyl}, @code{mbox}, @code{digest},
@code{mmdf}, @code{news}, @code{rnews}, @code{clari-briefs},
@code{rfc934}, @code{rfc822-forward}, @code{nsmail} and @code{forward}.
If you run this command without a prefix, Gnus will guess at the file
type.  @xref{Document Groups}.

@item G u
@kindex G u (Group)
@vindex gnus-useful-groups
@findex gnus-group-make-useful-group
Create one of the groups mentioned in @code{gnus-useful-groups}
(@code{gnus-group-make-useful-group}).

@item G w
@kindex G w (Group)
@findex gnus-group-make-web-group
@cindex DejaNews
@cindex Alta Vista
@cindex InReference
@cindex nnweb
Make an ephemeral group based on a web search
(@code{gnus-group-make-web-group}).  If you give a prefix to this
command, make a solid group instead.  You will be prompted for the
search engine type and the search string.  Valid search engine types
include @code{dejanews}, @code{altavista} and @code{reference}.
@xref{Web Searches}.

If you use the @code{dejanews} search engine, you can limit the search
to a particular group by using a match string like
@samp{~g alt.sysadmin.recovery shaving}.

@item G DEL
@kindex G DEL (Group)
@findex gnus-group-delete-group
This function will delete the current group
(@code{gnus-group-delete-group}).  If given a prefix, this function will
actually delete all the articles in the group, and forcibly remove the
group itself from the face of the Earth.  Use a prefix only if you are
absolutely sure of what you are doing.  This command can't be used on
read-only groups (like @code{nntp} group), though.

@item G V
@kindex G V (Group)
@findex gnus-group-make-empty-virtual
Make a new, fresh, empty @code{nnvirtual} group
(@code{gnus-group-make-empty-virtual}).  @xref{Virtual Groups}.

@item G v
@kindex G v (Group)
@findex gnus-group-add-to-virtual
Add the current group to an @code{nnvirtual} group
(@code{gnus-group-add-to-virtual}).  Uses the process/prefix convention.
@end table

@xref{Select Methods}, for more information on the various select
methods.

@vindex gnus-activate-foreign-newsgroups
If @code{gnus-activate-foreign-newsgroups} is a positive number,
Gnus will check all foreign groups with this level or lower at startup.
This might take quite a while, especially if you subscribe to lots of
groups from different @sc{nntp} servers.  Also @pxref{Group Levels};
@code{gnus-activate-level} also affects activation of foreign
newsgroups.


@node Group Parameters
@section Group Parameters
@cindex group parameters

The group parameters store information local to a particular group.
Here's an example group parameter list:

@example
((to-address . "ding@@gnus.org")
 (auto-expire . t))
@end example

We see that each element consists of a "dotted pair"---the thing before
the dot is the key, while the thing after the dot is the value.  All the
parameters have this form @emph{except} local variable specs, which are
not dotted pairs, but proper lists.

The following group parameters can be used:

@table @code
@item to-address
@cindex to-address
Address used by when doing followups and new posts.

@example
(to-address .  "some@@where.com")
@end example

This is primarily useful in mail groups that represent closed mailing
lists---mailing lists where it's expected that everybody that writes to
the mailing list is subscribed to it.  Since using this parameter
ensures that the mail only goes to the mailing list itself, it means
that members won't receive two copies of your followups.

Using @code{to-address} will actually work whether the group is foreign
or not.  Let's say there's a group on the server that is called
@samp{fa.4ad-l}.  This is a real newsgroup, but the server has gotten
the articles from a mail-to-news gateway.  Posting directly to this
group is therefore impossible---you have to send mail to the mailing
list address instead.

@item to-list
@cindex to-list
Address used when doing @kbd{a} in that group.

@example
(to-list . "some@@where.com")
@end example

It is totally ignored
when doing a followup---except that if it is present in a news group,
you'll get mail group semantics when doing @kbd{f}.

If you do an @kbd{a} command in a mail group and you have neither a
@code{to-list} group parameter nor a @code{to-address} group parameter,
then a @code{to-list} group parameter will be added automatically upon
sending the message if @code{gnus-add-to-list} is set to @code{t}.
@vindex gnus-add-to-list

If you do an @kbd{a} command in a mail group and you don't have a
@code{to-list} group parameter, one will be added automatically upon
sending the message.

@item visible
@cindex visible
If the group parameter list has the element @code{(visible . t)},
that group will always be visible in the Group buffer, regardless
of whether it has any unread articles.

@item broken-reply-to
@cindex broken-reply-to
Elements like @code{(broken-reply-to . t)} signals that @code{Reply-To}
headers in this group are to be ignored.  This can be useful if you're
reading a mailing list group where the listserv has inserted
@code{Reply-To} headers that point back to the listserv itself.  This is
broken behavior.  So there!

@item to-group
@cindex to-group
Elements like @code{(to-group . "some.group.name")} means that all
posts in that group will be sent to @code{some.group.name}.

@item newsgroup
@cindex newsgroup
If you have @code{(newsgroup . t)} in the group parameter list, Gnus
will treat all responses as if they were responses to news articles.
This can be useful if you have a mail group that's really a mirror of a
news group.

@item gcc-self
@cindex gcc-self
If @code{(gcc-self . t)} is present in the group parameter list, newly
composed messages will be @code{Gcc}'d to the current group.  If
@code{(gcc-self . none)} is present, no @code{Gcc:} header will be
generated, if @code{(gcc-self . "string")} is present, this string will
be inserted literally as a @code{gcc} header.  This parameter takes
precedence over any default @code{Gcc} rules as described later
(@pxref{Archived Messages}).

@item auto-expire
@cindex auto-expire
If the group parameter has an element that looks like @code{(auto-expire
. t)}, all articles read will be marked as expirable.  For an
alternative approach, @pxref{Expiring Mail}.

@item total-expire
@cindex total-expire
If the group parameter has an element that looks like
@code{(total-expire . t)}, all read articles will be put through the
expiry process, even if they are not marked as expirable.  Use with
caution.  Unread, ticked and dormant articles are not eligible for
expiry.

@item expiry-wait
@cindex expiry-wait
@vindex nnmail-expiry-wait-function
If the group parameter has an element that looks like @code{(expiry-wait
. 10)}, this value will override any @code{nnmail-expiry-wait} and
@code{nnmail-expiry-wait-function} when expiring expirable messages.
The value can either be a number of days (not necessarily an integer) or
the symbols @code{never} or @code{immediate}.

@item score-file
@cindex score file group parameter
Elements that look like @code{(score-file . "file")} will make
@file{file} into the current score file for the group in question.  All
interactive score entries will be put into this file.

@item adapt-file
@cindex adapt file group parameter
Elements that look like @code{(adapt-file . "file")} will make
@file{file} into the current adaptive file for the group in question.
All adaptive score entries will be put into this file.

@item admin-address
When unsubscribing from a mailing list you should never send the
unsubscription notice to the mailing list itself.  Instead, you'd send
messages to the administrative address.  This parameter allows you to
put the admin address somewhere convenient.

@item display
Elements that look like @code{(display . MODE)} say which articles to
display on entering the group.  Valid values are:

@table @code
@item all
Display all articles, both read and unread.

@item default
Display the default visible articles, which normally includes unread and
ticked articles.
@end table

@item comment
Elements that look like @code{(comment . "This is a comment")}
are arbitrary comments on the group.  They are currently ignored by
Gnus, but provide a place for you to store information on particular
groups.

@item charset
Elements that look like @code{(charset . iso-8859-1)} will make
@code{iso-8859-1} the default charset; that is, the charset that will be
used for all articles that do not specify a charset.

@item (@var{variable} @var{form})
You can use the group parameters to set variables local to the group you
are entering.  If you want to turn threading off in @samp{news.answers},
you could put @code{(gnus-show-threads nil)} in the group parameters of
that group.  @code{gnus-show-threads} will be made into a local variable
in the summary buffer you enter, and the form @code{nil} will be
@code{eval}ed there.

This can also be used as a group-specific hook function, if you'd like.
If you want to hear a beep when you enter a group, you could put
something like @code{(dummy-variable (ding))} in the parameters of that
group.  @code{dummy-variable} will be set to the result of the
@code{(ding)} form, but who cares?

@item posting-style
You can store additional posting style information for this group only
here (@pxref{Posting Styles}).  The format is that of an entry in the
@code{gnus-posting-styles} alist, except that there's no regexp matching
the group name (of course).  Style elements in this group parameter will
take precedence over the ones found in @code{gnus-posting-styles}.

For instance, if you want a funky name and signature in this group only,
instead of hacking @code{gnus-posting-styles}, you could put something
like this in the group parameters:

@example
(posting-style
  (name "Funky Name")
  (signature "Funky Signature"))
@end example

@item banner
An item like @code{(banner . "regex")} causes any part of an article
that matches the regular expression "regex" to be stripped. Instead of
"regex", you can also use the symbol @code{signature} which strips the
last signature or any of the elements of the alist
@code{gnus-article-banner-alist}.

@end table

Use the @kbd{G p} command to edit group parameters of a group.  You
might also be interested in reading about topic parameters (@pxref{Topic
Parameters}).


@node Listing Groups
@section Listing Groups
@cindex group listing

These commands all list various slices of the groups available.

@table @kbd

@item l
@itemx A s
@kindex A s (Group)
@kindex l (Group)
@findex gnus-group-list-groups
List all groups that have unread articles
(@code{gnus-group-list-groups}).  If the numeric prefix is used, this
command will list only groups of level ARG and lower.  By default, it
only lists groups of level five (i. e.,
@code{gnus-group-default-list-level}) or lower (i.e., just subscribed
groups).

@item L
@itemx A u
@kindex A u (Group)
@kindex L (Group)
@findex gnus-group-list-all-groups
List all groups, whether they have unread articles or not
(@code{gnus-group-list-all-groups}).  If the numeric prefix is used,
this command will list only groups of level ARG and lower.  By default,
it lists groups of level seven or lower (i.e., just subscribed and
unsubscribed groups).

@item A l
@kindex A l (Group)
@findex gnus-group-list-level
List all unread groups on a specific level
(@code{gnus-group-list-level}).  If given a prefix, also list the groups
with no unread articles.

@item A k
@kindex A k (Group)
@findex gnus-group-list-killed
List all killed groups (@code{gnus-group-list-killed}).  If given a
prefix argument, really list all groups that are available, but aren't
currently (un)subscribed.  This could entail reading the active file
from the server.

@item A z
@kindex A z (Group)
@findex gnus-group-list-zombies
List all zombie groups (@code{gnus-group-list-zombies}).

@item A m
@kindex A m (Group)
@findex gnus-group-list-matching
List all unread, subscribed groups with names that match a regexp
(@code{gnus-group-list-matching}).

@item A M
@kindex A M (Group)
@findex gnus-group-list-all-matching
List groups that match a regexp (@code{gnus-group-list-all-matching}).

@item A A
@kindex A A (Group)
@findex gnus-group-list-active
List absolutely all groups in the active file(s) of the
server(s) you are connected to (@code{gnus-group-list-active}).  This
might very well take quite a while.  It might actually be a better idea
to do a @kbd{A M} to list all matching, and just give @samp{.} as the
thing to match on.  Also note that this command may list groups that
don't exist (yet)---these will be listed as if they were killed groups.
Take the output with some grains of salt.

@item A a
@kindex A a (Group)
@findex gnus-group-apropos
List all groups that have names that match a regexp
(@code{gnus-group-apropos}).

@item A d
@kindex A d (Group)
@findex gnus-group-description-apropos
List all groups that have names or descriptions that match a regexp
(@code{gnus-group-description-apropos}).

@item A c
@kindex A c (Group)
@findex gnus-group-list-cached
List all groups with cached articles (@code{gnus-group-list-cached}).

@item A ?
@kindex A ? (Group)
@findex gnus-group-list-dormant
List all groups with dormant articles (@code{gnus-group-list-dormant}).

@item A /
@kindex A / (Group)
@findex gnus-group-list-limit
List groups limited within the current selection
(@code{gnus-group-list-limit}).

@item A f
@kindex A f (Group)
@findex gnus-group-list-flush
Flush groups from the current selection (@code{gnus-group-list-flush}).

@item A p
@kindex A p (Group)
@findex gnus-group-list-plus
List groups plus the current selection (@code{gnus-group-list-plus}).

@end table

@vindex gnus-permanently-visible-groups
@cindex visible group parameter
Groups that match the @code{gnus-permanently-visible-groups} regexp will
always be shown, whether they have unread articles or not.  You can also
add the @code{visible} element to the group parameters in question to
get the same effect.

@vindex gnus-list-groups-with-ticked-articles
Groups that have just ticked articles in it are normally listed in the
group buffer.  If @code{gnus-list-groups-with-ticked-articles} is
@code{nil}, these groups will be treated just like totally empty
groups.  It is @code{t} by default.


@node Sorting Groups
@section Sorting Groups
@cindex sorting groups

@kindex C-c C-s (Group)
@findex gnus-group-sort-groups
@vindex gnus-group-sort-function
The @kbd{C-c C-s} (@code{gnus-group-sort-groups}) command sorts the
group buffer according to the function(s) given by the
@code{gnus-group-sort-function} variable.  Available sorting functions
include:

@table @code

@item gnus-group-sort-by-alphabet
@findex gnus-group-sort-by-alphabet
Sort the group names alphabetically.  This is the default.

@item gnus-group-sort-by-real-name
@findex gnus-group-sort-by-real-name
Sort the group alphabetically on the real (unprefixed) group names.

@item gnus-group-sort-by-level
@findex gnus-group-sort-by-level
Sort by group level.

@item gnus-group-sort-by-score
@findex gnus-group-sort-by-score
Sort by group score.  @xref{Group Score}.

@item gnus-group-sort-by-rank
@findex gnus-group-sort-by-rank
Sort by group score and then the group level.  The level and the score
are, when taken together, the group's @dfn{rank}.  @xref{Group Score}.

@item gnus-group-sort-by-unread
@findex gnus-group-sort-by-unread
Sort by number of unread articles.

@item gnus-group-sort-by-method
@findex gnus-group-sort-by-method
Sort alphabetically on the select method.


@end table

@code{gnus-group-sort-function} can also be a list of sorting
functions.  In that case, the most significant sort key function must be
the last one.


There are also a number of commands for sorting directly according to
some sorting criteria:

@table @kbd
@item G S a
@kindex G S a (Group)
@findex gnus-group-sort-groups-by-alphabet
Sort the group buffer alphabetically by group name
(@code{gnus-group-sort-groups-by-alphabet}).

@item G S u
@kindex G S u (Group)
@findex gnus-group-sort-groups-by-unread
Sort the group buffer by the number of unread articles
(@code{gnus-group-sort-groups-by-unread}).

@item G S l
@kindex G S l (Group)
@findex gnus-group-sort-groups-by-level
Sort the group buffer by group level
(@code{gnus-group-sort-groups-by-level}).

@item G S v
@kindex G S v (Group)
@findex gnus-group-sort-groups-by-score
Sort the group buffer by group score
(@code{gnus-group-sort-groups-by-score}).  @xref{Group Score}.

@item G S r
@kindex G S r (Group)
@findex gnus-group-sort-groups-by-rank
Sort the group buffer by group rank
(@code{gnus-group-sort-groups-by-rank}).  @xref{Group Score}.

@item G S m
@kindex G S m (Group)
@findex gnus-group-sort-groups-by-method
Sort the group buffer alphabetically by backend name
(@code{gnus-group-sort-groups-by-method}).

@end table

All the commands below obey the process/prefix convention
(@pxref{Process/Prefix}).

When given a symbolic prefix (@pxref{Symbolic Prefixes}), all these
commands will sort in reverse order.

You can also sort a subset of the groups:

@table @kbd
@item G P a
@kindex G P a (Group)
@findex gnus-group-sort-selected-groups-by-alphabet
Sort the groups alphabetically by group name
(@code{gnus-group-sort-selected-groups-by-alphabet}).

@item G P u
@kindex G P u (Group)
@findex gnus-group-sort-selected-groups-by-unread
Sort the groups by the number of unread articles
(@code{gnus-group-sort-selected-groups-by-unread}).

@item G P l
@kindex G P l (Group)
@findex gnus-group-sort-selected-groups-by-level
Sort the groups by group level
(@code{gnus-group-sort-selected-groups-by-level}).

@item G P v
@kindex G P v (Group)
@findex gnus-group-sort-selected-groups-by-score
Sort the groups by group score
(@code{gnus-group-sort-selected-groups-by-score}).  @xref{Group Score}.

@item G P r
@kindex G P r (Group)
@findex gnus-group-sort-selected-groups-by-rank
Sort the groups by group rank
(@code{gnus-group-sort-selected-groups-by-rank}).  @xref{Group Score}.

@item G P m
@kindex G P m (Group)
@findex gnus-group-sort-selected-groups-by-method
Sort the groups alphabetically by backend name
(@code{gnus-group-sort-selected-groups-by-method}).

@end table



@node Group Maintenance
@section Group Maintenance
@cindex bogus groups

@table @kbd
@item b
@kindex b (Group)
@findex gnus-group-check-bogus-groups
Find bogus groups and delete them
(@code{gnus-group-check-bogus-groups}).

@item F
@kindex F (Group)
@findex gnus-group-find-new-groups
Find new groups and process them (@code{gnus-group-find-new-groups}).
With 1 @kbd{C-u}, use the @code{ask-server} method to query the server
for new groups.  With 2 @kbd{C-u}'s, use most complete method possible
to query the server for new groups, and subscribe the new groups as
zombies.

@item C-c C-x
@kindex C-c C-x (Group)
@findex gnus-group-expire-articles
Run all expirable articles in the current group through the expiry
process (if any) (@code{gnus-group-expire-articles}).

@item C-c M-C-x
@kindex C-c M-C-x (Group)
@findex gnus-group-expire-all-groups
Run all articles in all groups through the expiry process
(@code{gnus-group-expire-all-groups}).

@end table


@node Browse Foreign Server
@section Browse Foreign Server
@cindex foreign servers
@cindex browsing servers

@table @kbd
@item B
@kindex B (Group)
@findex gnus-group-browse-foreign-server
You will be queried for a select method and a server name.  Gnus will
then attempt to contact this server and let you browse the groups there
(@code{gnus-group-browse-foreign-server}).
@end table

@findex gnus-browse-mode
A new buffer with a list of available groups will appear.  This buffer
will use the @code{gnus-browse-mode}.  This buffer looks a bit (well,
a lot) like a normal group buffer.

Here's a list of keystrokes available in the browse mode:

@table @kbd
@item n
@kindex n (Browse)
@findex gnus-group-next-group
Go to the next group (@code{gnus-group-next-group}).

@item p
@kindex p (Browse)
@findex gnus-group-prev-group
Go to the previous group (@code{gnus-group-prev-group}).

@item SPACE
@kindex SPACE (Browse)
@findex gnus-browse-read-group
Enter the current group and display the first article
(@code{gnus-browse-read-group}).

@item RET
@kindex RET (Browse)
@findex gnus-browse-select-group
Enter the current group (@code{gnus-browse-select-group}).

@item u
@kindex u (Browse)
@findex gnus-browse-unsubscribe-current-group
Unsubscribe to the current group, or, as will be the case here,
subscribe to it (@code{gnus-browse-unsubscribe-current-group}).

@item l
@itemx q
@kindex q (Browse)
@kindex l (Browse)
@findex gnus-browse-exit
Exit browse mode (@code{gnus-browse-exit}).

@item ?
@kindex ? (Browse)
@findex gnus-browse-describe-briefly
Describe browse mode briefly (well, there's not much to describe, is
there) (@code{gnus-browse-describe-briefly}).
@end table


@node Exiting Gnus
@section Exiting Gnus
@cindex exiting Gnus

Yes, Gnus is ex(c)iting.

@table @kbd
@item z
@kindex z (Group)
@findex gnus-group-suspend
Suspend Gnus (@code{gnus-group-suspend}).  This doesn't really exit Gnus,
but it kills all buffers except the Group buffer.  I'm not sure why this
is a gain, but then who am I to judge?

@item q
@kindex q (Group)
@findex gnus-group-exit
@c @icon{gnus-group-exit}
Quit Gnus (@code{gnus-group-exit}).

@item Q
@kindex Q (Group)
@findex gnus-group-quit
Quit Gnus without saving the @file{.newsrc} files (@code{gnus-group-quit}).
The dribble file will be saved, though (@pxref{Auto Save}).
@end table

@vindex gnus-exit-gnus-hook
@vindex gnus-suspend-gnus-hook
@code{gnus-suspend-gnus-hook} is called when you suspend Gnus and
@code{gnus-exit-gnus-hook} is called when you quit Gnus, while
@code{gnus-after-exiting-gnus-hook} is called as the final item when
exiting Gnus.

@findex gnus-unload
@cindex unloading
If you wish to completely unload Gnus and all its adherents, you can use
the @code{gnus-unload} command.  This command is also very handy when
trying to customize meta-variables.

Note:

@quotation
Miss Lisa Cannifax, while sitting in English class, felt her feet go
numbly heavy and herself fall into a hazy trance as the boy sitting
behind her drew repeated lines with his pencil across the back of her
plastic chair.
@end quotation


@node Group Topics
@section Group Topics
@cindex topics

If you read lots and lots of groups, it might be convenient to group
them hierarchically according to topics.  You put your Emacs groups over
here, your sex groups over there, and the rest (what, two groups or so?)
you put in some misc section that you never bother with anyway.  You can
even group the Emacs sex groups as a sub-topic to either the Emacs
groups or the sex groups---or both!  Go wild!

@iftex
@iflatex
\gnusfigure{Group Topics}{400}{
\put(75,50){\epsfig{figure=tmp/group-topic.ps,height=9cm}}
}
@end iflatex
@end iftex

Here's an example:

@example
Gnus
  Emacs -- I wuw it!
     3: comp.emacs
     2: alt.religion.emacs
    Naughty Emacs
     452: alt.sex.emacs
       0: comp.talk.emacs.recovery
  Misc
     8: comp.binaries.fractals
    13: comp.sources.unix
@end example

@findex gnus-topic-mode
@kindex t (Group)
To get this @emph{fab} functionality you simply turn on (ooh!) the
@code{gnus-topic} minor mode---type @kbd{t} in the group buffer.  (This
is a toggling command.)

Go ahead, just try it.  I'll still be here when you get back.  La de
dum...  Nice tune, that...  la la la...  What, you're back? Yes, and now
press @kbd{l}.  There.  All your groups are now listed under
@samp{misc}.  Doesn't that make you feel all warm and fuzzy?  Hot and
bothered?

If you want this permanently enabled, you should add that minor mode to
the hook for the group mode:

@lisp
(add-hook 'gnus-group-mode-hook 'gnus-topic-mode)
@end lisp

@menu
* Topic Variables::    How to customize the topics the Lisp Way.
* Topic Commands::     Interactive E-Z commands.
* Topic Sorting::      Sorting each topic individually.
* Topic Topology::     A map of the world.
* Topic Parameters::   Parameters that apply to all groups in a topic.
@end menu


@node Topic Variables
@subsection Topic Variables
@cindex topic variables

Now, if you select a topic, it will fold/unfold that topic, which is
really neat, I think.

@vindex gnus-topic-line-format
The topic lines themselves are created according to the
@code{gnus-topic-line-format} variable (@pxref{Formatting Variables}).
Valid elements are:

@table @samp
@item i
Indentation.
@item n
Topic name.
@item v
Visibility.
@item l
Level.
@item g
Number of groups in the topic.
@item a
Number of unread articles in the topic.
@item A
Number of unread articles in the topic and all its subtopics.
@end table

@vindex gnus-topic-indent-level
Each sub-topic (and the groups in the sub-topics) will be indented with
@code{gnus-topic-indent-level} times the topic level number of spaces.
The default is 2.

@vindex gnus-topic-mode-hook
@code{gnus-topic-mode-hook} is called in topic minor mode buffers.

@vindex gnus-topic-display-empty-topics
The @code{gnus-topic-display-empty-topics} says whether to display even
topics that have no unread articles in them.  The default is @code{t}.


@node Topic Commands
@subsection Topic Commands
@cindex topic commands

When the topic minor mode is turned on, a new @kbd{T} submap will be
available.  In addition, a few of the standard keys change their
definitions slightly.

@table @kbd

@item T n
@kindex T n (Topic)
@findex gnus-topic-create-topic
Prompt for a new topic name and create it
(@code{gnus-topic-create-topic}).

@item T m
@kindex T m (Topic)
@findex gnus-topic-move-group
Move the current group to some other topic
(@code{gnus-topic-move-group}).  This command uses the process/prefix
convention (@pxref{Process/Prefix}).

@item T j
@kindex T j (Topic)
@findex gnus-topic-jump-to-topic
Go to a topic (@code{gnus-topic-jump-to-topic}).  

@item T c
@kindex T c (Topic)
@findex gnus-topic-copy-group
Copy the current group to some other topic
(@code{gnus-topic-copy-group}).  This command uses the process/prefix
convention (@pxref{Process/Prefix}).

@item T h
@kindex T h (Topic)
@findex gnus-topic-hide-topic
Hide the current topic (@code{gnus-topic-hide-topic}).  If given
a prefix, hide the topic permanently.

@item T s
@kindex T s (Topic)
@findex gnus-topic-show-topic
Show the current topic (@code{gnus-topic-show-topic}).  If given
a prefix, show the topic permanently.

@item T D
@kindex T D (Topic)
@findex gnus-topic-remove-group
Remove a group from the current topic (@code{gnus-topic-remove-group}).
This command is mainly useful if you have the same group in several
topics and wish to remove it from one of the topics.  You may also
remove a group from all topics, but in that case, Gnus will add it to
the root topic the next time you start Gnus.  In fact, all new groups
(which, naturally, don't belong to any topic) will show up in the root
topic.

This command uses the process/prefix convention
(@pxref{Process/Prefix}).

@item T M
@kindex T M (Topic)
@findex gnus-topic-move-matching
Move all groups that match some regular expression to a topic
(@code{gnus-topic-move-matching}).

@item T C
@kindex T C (Topic)
@findex gnus-topic-copy-matching
Copy all groups that match some regular expression to a topic
(@code{gnus-topic-copy-matching}).

@item T H
@kindex T H (Topic)
@findex gnus-topic-toggle-display-empty-topics
Toggle hiding empty topics
(@code{gnus-topic-toggle-display-empty-topics}).

@item T #
@kindex T # (Topic)
@findex gnus-topic-mark-topic
Mark all groups in the current topic with the process mark
(@code{gnus-topic-mark-topic}).

@item T M-#
@kindex T M-# (Topic)
@findex gnus-topic-unmark-topic
Remove the process mark from all groups in the current topic
(@code{gnus-topic-unmark-topic}).

@item T TAB
@itemx TAB
@kindex T TAB (Topic)
@kindex TAB (Topic)
@findex gnus-topic-indent
``Indent'' the current topic so that it becomes a sub-topic of the
previous topic (@code{gnus-topic-indent}).  If given a prefix,
``un-indent'' the topic instead.

@item M-TAB
@kindex M-TAB (Topic)
@findex gnus-topic-unindent
``Un-indent'' the current topic so that it becomes a sub-topic of the
parent of its current parent (@code{gnus-topic-unindent}).

@item RET
@kindex RET (Topic)
@findex gnus-topic-select-group
@itemx SPACE
Either select a group or fold a topic (@code{gnus-topic-select-group}).
When you perform this command on a group, you'll enter the group, as
usual.  When done on a topic line, the topic will be folded (if it was
visible) or unfolded (if it was folded already).  So it's basically a
toggling command on topics.  In addition, if you give a numerical
prefix, group on that level (and lower) will be displayed.

@item C-c C-x
@kindex C-c C-x (Topic)
@findex gnus-topic-expire-articles
Run all expirable articles in the current group or topic through the expiry
process (if any) (@code{gnus-topic-expire-articles}).

@item C-k
@kindex C-k (Topic)
@findex gnus-topic-kill-group
Kill a group or topic (@code{gnus-topic-kill-group}).  All groups in the
topic will be removed along with the topic.

@item C-y
@kindex C-y (Topic)
@findex gnus-topic-yank-group
Yank the previously killed group or topic
(@code{gnus-topic-yank-group}).  Note that all topics will be yanked
before all groups.

@item T r
@kindex T r (Topic)
@findex gnus-topic-rename
Rename a topic (@code{gnus-topic-rename}).

@item T DEL
@kindex T DEL (Topic)
@findex gnus-topic-delete
Delete an empty topic (@code{gnus-topic-delete}).

@item A T
@kindex A T (Topic)
@findex gnus-topic-list-active
List all groups that Gnus knows about in a topics-ified way
(@code{gnus-topic-list-active}).

@item G p
@kindex G p (Topic)
@findex gnus-topic-edit-parameters
@cindex group parameters
@cindex topic parameters
@cindex parameters
Edit the topic parameters (@code{gnus-topic-edit-parameters}).
@xref{Topic Parameters}.

@end table


@node Topic Sorting
@subsection Topic Sorting
@cindex topic sorting

You can sort the groups in each topic individually with the following
commands:


@table @kbd
@item T S a
@kindex T S a (Topic)
@findex gnus-topic-sort-groups-by-alphabet
Sort the current topic alphabetically by group name
(@code{gnus-topic-sort-groups-by-alphabet}).

@item T S u
@kindex T S u (Topic)
@findex gnus-topic-sort-groups-by-unread
Sort the current topic by the number of unread articles
(@code{gnus-topic-sort-groups-by-unread}).

@item T S l
@kindex T S l (Topic)
@findex gnus-topic-sort-groups-by-level
Sort the current topic by group level
(@code{gnus-topic-sort-groups-by-level}).

@item T S v
@kindex T S v (Topic)
@findex gnus-topic-sort-groups-by-score
Sort the current topic by group score
(@code{gnus-topic-sort-groups-by-score}).  @xref{Group Score}.

@item T S r
@kindex T S r (Topic)
@findex gnus-topic-sort-groups-by-rank
Sort the current topic by group rank
(@code{gnus-topic-sort-groups-by-rank}).  @xref{Group Score}.

@item T S m
@kindex T S m (Topic)
@findex gnus-topic-sort-groups-by-method
Sort the current topic alphabetically by backend name
(@code{gnus-topic-sort-groups-by-method}).

@end table

@xref{Sorting Groups}, for more information about group sorting.


@node Topic Topology
@subsection Topic Topology
@cindex topic topology
@cindex topology

So, let's have a look at an example group buffer:

@example
Gnus
  Emacs -- I wuw it!
     3: comp.emacs
     2: alt.religion.emacs
    Naughty Emacs
     452: alt.sex.emacs
       0: comp.talk.emacs.recovery
  Misc
     8: comp.binaries.fractals
    13: comp.sources.unix
@end example

So, here we have one top-level topic (@samp{Gnus}), two topics under
that, and one sub-topic under one of the sub-topics.  (There is always
just one (1) top-level topic).  This topology can be expressed as
follows:

@lisp
(("Gnus" visible)
 (("Emacs -- I wuw it!" visible)
  (("Naughty Emacs" visible)))
 (("Misc" visible)))
@end lisp

@vindex gnus-topic-topology
This is in fact how the variable @code{gnus-topic-topology} would look
for the display above.  That variable is saved in the @file{.newsrc.eld}
file, and shouldn't be messed with manually---unless you really want
to.  Since this variable is read from the @file{.newsrc.eld} file,
setting it in any other startup files will have no effect.

This topology shows what topics are sub-topics of what topics (right),
and which topics are visible.  Two settings are currently
allowed---@code{visible} and @code{invisible}.


@node Topic Parameters
@subsection Topic Parameters
@cindex topic parameters

All groups in a topic will inherit group parameters from the parent (and
ancestor) topic parameters.  All valid group parameters are valid topic
parameters (@pxref{Group Parameters}).

In addition, the following parameters are only valid as topic
parameters:

@table @code
@item subscribe
When subscribing new groups by topic (@pxref{Subscription Methods}), the 
@code{subscribe} topic parameter says what groups go in what topic.  Its 
value should be a regexp to match the groups that should go in that
topic. 

@end table

Group parameters (of course) override topic parameters, and topic
parameters in sub-topics override topic parameters in super-topics.  You
know.  Normal inheritance rules.  (@dfn{Rules} is here a noun, not a
verb, although you may feel free to disagree with me here.)

@example
Gnus
  Emacs
     3: comp.emacs
     2: alt.religion.emacs
   452: alt.sex.emacs
    Relief
     452: alt.sex.emacs
       0: comp.talk.emacs.recovery
  Misc
     8: comp.binaries.fractals
    13: comp.sources.unix
   452: alt.sex.emacs
@end example

The @samp{Emacs} topic has the topic parameter @code{(score-file
. "emacs.SCORE")}; the @samp{Relief} topic has the topic parameter
@code{(score-file . "relief.SCORE")}; and the @samp{Misc} topic has the
topic parameter @code{(score-file . "emacs.SCORE")}.  In addition,
@* @samp{alt.religion.emacs} has the group parameter @code{(score-file
. "religion.SCORE")}.

Now, when you enter @samp{alt.sex.emacs} in the @samp{Relief} topic, you
will get the @file{relief.SCORE} home score file.  If you enter the same
group in the @samp{Emacs} topic, you'll get the @file{emacs.SCORE} home
score file.  If you enter the group @samp{alt.religion.emacs}, you'll
get the @file{religion.SCORE} home score file.

This seems rather simple and self-evident, doesn't it?  Well, yes.  But
there are some problems, especially with the @code{total-expiry}
parameter.  Say you have a mail group in two topics; one with
@code{total-expiry} and one without.  What happens when you do @kbd{M-x
gnus-expire-all-expirable-groups}?  Gnus has no way of telling which one
of these topics you mean to expire articles from, so anything may
happen.  In fact, I hereby declare that it is @dfn{undefined} what
happens.  You just have to be careful if you do stuff like that.


@node Misc Group Stuff
@section Misc Group Stuff

@menu
* Scanning New Messages:: Asking Gnus to see whether new messages have arrived.
* Group Information::     Information and help on groups and Gnus.
* Group Timestamp::       Making Gnus keep track of when you last read a group.
* File Commands::         Reading and writing the Gnus files.
@end menu

@table @kbd

@item ^
@kindex ^ (Group)
@findex gnus-group-enter-server-mode
Enter the server buffer (@code{gnus-group-enter-server-mode}).
@xref{The Server Buffer}.

@item a
@kindex a (Group)
@findex gnus-group-post-news
Post an article to a group (@code{gnus-group-post-news}).  If given a
prefix, the current group name will be used as the default.

@item m
@kindex m (Group)
@findex gnus-group-mail
Mail a message somewhere (@code{gnus-group-mail}).

@end table

Variables for the group buffer:

@table @code

@item gnus-group-mode-hook
@vindex gnus-group-mode-hook
is called after the group buffer has been
created.

@item gnus-group-prepare-hook
@vindex gnus-group-prepare-hook
is called after the group buffer is
generated.  It may be used to modify the buffer in some strange,
unnatural way.

@item gnus-group-prepared-hook
@vindex gnus-group-prepare-hook
is called as the very last thing after the group buffer has been
generated.  It may be used to move point around, for instance.

@item gnus-permanently-visible-groups
@vindex gnus-permanently-visible-groups
Groups matching this regexp will always be listed in the group buffer,
whether they are empty or not.

@item gnus-group-name-charset-method-alist
@vindex gnus-group-name-charset-method-alist
An alist of method and the charset for group names. It is used to show
non-ASCII group names.

For example:
@lisp
(setq gnus-group-name-charset-method-alist
    '(((nntp "news.com.cn") . cn-gb-2312)))
@end lisp

@item gnus-group-name-charset-group-alist
@vindex gnus-group-name-charset-group-alist
An alist of regexp of group name and the charset for group names. 
It is used to show non-ASCII group names.

For example:
@lisp
(setq gnus-group-name-charset-group-alist
    '(("\\.com\\.cn:" . cn-gb-2312)))
@end lisp

@end table

@node Scanning New Messages
@subsection Scanning New Messages
@cindex new messages
@cindex scanning new news

@table @kbd

@item g
@kindex g (Group)
@findex gnus-group-get-new-news
@c @icon{gnus-group-get-new-news}
Check the server(s) for new articles.  If the numerical prefix is used,
this command will check only groups of level @var{arg} and lower
(@code{gnus-group-get-new-news}).  If given a non-numerical prefix, this
command will force a total re-reading of the active file(s) from the
backend(s).

@item M-g
@kindex M-g (Group)
@findex gnus-group-get-new-news-this-group
@vindex gnus-goto-next-group-when-activating
@c @icon{gnus-group-get-new-news-this-group}
Check whether new articles have arrived in the current group
(@code{gnus-group-get-new-news-this-group}).
@code{gnus-goto-next-group-when-activating} says whether this command is
to move point to the next group or not.  It is @code{t} by default.

@findex gnus-activate-all-groups
@cindex activating groups
@item C-c M-g
@kindex C-c M-g (Group)
Activate absolutely all groups (@code{gnus-activate-all-groups}).

@item R
@kindex R (Group)
@cindex restarting
@findex gnus-group-restart
Restart Gnus (@code{gnus-group-restart}).  This saves the @file{.newsrc}
file(s), closes the connection to all servers, clears up all run-time
Gnus variables, and then starts Gnus all over again.

@end table

@vindex gnus-get-new-news-hook
@code{gnus-get-new-news-hook} is run just before checking for new news.

@vindex gnus-after-getting-new-news-hook
@code{gnus-after-getting-new-news-hook} is run after checking for new
news.


@node Group Information
@subsection Group Information
@cindex group information
@cindex information on groups

@table @kbd


@item H f
@kindex H f (Group)
@findex gnus-group-fetch-faq
@vindex gnus-group-faq-directory
@cindex FAQ
@cindex ange-ftp
Try to fetch the FAQ for the current group
(@code{gnus-group-fetch-faq}).  Gnus will try to get the FAQ from
@code{gnus-group-faq-directory}, which is usually a directory on a
remote machine.  This variable can also be a list of directories.  In
that case, giving a prefix to this command will allow you to choose
between the various sites.  @code{ange-ftp} (or @code{efs}) will be used
for fetching the file.

If fetching from the first site is unsuccessful, Gnus will attempt to go
through @code{gnus-group-faq-directory} and try to open them one by one.

@item H d
@itemx C-c C-d
@c @icon{gnus-group-describe-group}
@kindex H d (Group)
@kindex C-c C-d (Group)
@cindex describing groups
@cindex group description
@findex gnus-group-describe-group
Describe the current group (@code{gnus-group-describe-group}).  If given
a prefix, force Gnus to re-read the description from the server.

@item M-d
@kindex M-d (Group)
@findex gnus-group-describe-all-groups
Describe all groups (@code{gnus-group-describe-all-groups}).  If given a
prefix, force Gnus to re-read the description file from the server.

@item H v
@itemx V
@kindex V (Group)
@kindex H v (Group)
@cindex version
@findex gnus-version
Display current Gnus version numbers (@code{gnus-version}).

@item ?
@kindex ? (Group)
@findex gnus-group-describe-briefly
Give a very short help message (@code{gnus-group-describe-briefly}).

@item C-c C-i
@kindex C-c C-i (Group)
@cindex info
@cindex manual
@findex gnus-info-find-node
Go to the Gnus info node (@code{gnus-info-find-node}).
@end table


@node Group Timestamp
@subsection Group Timestamp
@cindex timestamps
@cindex group timestamps

It can be convenient to let Gnus keep track of when you last read a
group.  To set the ball rolling, you should add
@code{gnus-group-set-timestamp} to @code{gnus-select-group-hook}:

@lisp
(add-hook 'gnus-select-group-hook 'gnus-group-set-timestamp)
@end lisp

After doing this, each time you enter a group, it'll be recorded.

This information can be displayed in various ways---the easiest is to
use the @samp{%d} spec in the group line format:

@lisp
(setq gnus-group-line-format
      "%M\%S\%p\%P\%5y: %(%-40,40g%) %d\n")
@end lisp

This will result in lines looking like:

@example
*        0: mail.ding                                19961002T012943
         0: custom                                   19961002T012713
@end example

As you can see, the date is displayed in compact ISO 8601 format.  This
may be a bit too much, so to just display the date, you could say
something like:

@lisp
(setq gnus-group-line-format
      "%M\%S\%p\%P\%5y: %(%-40,40g%) %6,6~(cut 2)d\n")
@end lisp


@node File Commands
@subsection File Commands
@cindex file commands

@table @kbd

@item r
@kindex r (Group)
@findex gnus-group-read-init-file
@vindex gnus-init-file
@cindex reading init file
Re-read the init file (@code{gnus-init-file}, which defaults to
@file{~/.gnus}) (@code{gnus-group-read-init-file}).

@item s
@kindex s (Group)
@findex gnus-group-save-newsrc
@cindex saving .newsrc
Save the @file{.newsrc.eld} file (and @file{.newsrc} if wanted)
(@code{gnus-group-save-newsrc}).  If given a prefix, force saving the
file(s) whether Gnus thinks it is necessary or not.

@c @item Z
@c @kindex Z (Group)
@c @findex gnus-group-clear-dribble
@c Clear the dribble buffer (@code{gnus-group-clear-dribble}).

@end table


@node The Summary Buffer
@chapter The Summary Buffer
@cindex summary buffer

A line for each article is displayed in the summary buffer.  You can
move around, read articles, post articles and reply to articles.

The most common way to a summary buffer is to select a group from the
group buffer (@pxref{Selecting a Group}).

You can have as many summary buffers open as you wish.

@menu
* Summary Buffer Format::       Deciding how the summary buffer is to look.
* Summary Maneuvering::         Moving around the summary buffer.
* Choosing Articles::           Reading articles.
* Paging the Article::          Scrolling the current article.
* Reply Followup and Post::     Posting articles.
* Marking Articles::            Marking articles as read, expirable, etc.
* Limiting::                    You can limit the summary buffer.
* Threading::                   How threads are made.
* Sorting::                     How articles and threads are sorted.
* Asynchronous Fetching::       Gnus might be able to pre-fetch articles.
* Article Caching::             You may store articles in a cache.
* Persistent Articles::         Making articles expiry-resistant.
* Article Backlog::             Having already read articles hang around.
* Saving Articles::             Ways of customizing article saving.
* Decoding Articles::           Gnus can treat series of (uu)encoded articles.
* Article Treatment::           The article buffer can be mangled at will.
* MIME Commands::               Doing MIMEy things with the articles.
* Charsets::                    Character set issues.
* Article Commands::            Doing various things with the article buffer.
* Summary Sorting::             Sorting the summary buffer in various ways.
* Finding the Parent::          No child support? Get the parent.
* Alternative Approaches::      Reading using non-default summaries.
* Tree Display::                A more visual display of threads.
* Mail Group Commands::         Some commands can only be used in mail groups.
* Various Summary Stuff::       What didn't fit anywhere else.
* Exiting the Summary Buffer::  Returning to the Group buffer.
* Crosspost Handling::          How crossposted articles are dealt with.
* Duplicate Suppression::       An alternative when crosspost handling fails.
* Security::                    Decrypt and Verify.
@end menu


@node Summary Buffer Format
@section Summary Buffer Format
@cindex summary buffer format

@iftex
@iflatex
\gnusfigure{The Summary Buffer}{180}{
\put(0,0){\epsfig{figure=tmp/summary.ps,width=7.5cm}}
\put(445,0){\makebox(0,0)[br]{\epsfig{figure=tmp/summary-article.ps,width=7.5cm}}}
}
@end iflatex
@end iftex

@menu
* Summary Buffer Lines::     You can specify how summary lines should look.
* To From Newsgroups::       How to not display your own name.
* Summary Buffer Mode Line:: You can say how the mode line should look.
* Summary Highlighting::     Making the summary buffer all pretty and nice.
@end menu

@findex mail-extract-address-components
@findex gnus-extract-address-components
@vindex gnus-extract-address-components
Gnus will use the value of the @code{gnus-extract-address-components}
variable as a function for getting the name and address parts of a
@code{From} header.  Two pre-defined functions exist:
@code{gnus-extract-address-components}, which is the default, quite
fast, and too simplistic solution; and
@code{mail-extract-address-components}, which works very nicely, but is
slower.  The default function will return the wrong answer in 5% of the
cases.  If this is unacceptable to you, use the other function instead:

@lisp
(setq gnus-extract-address-components
      'mail-extract-address-components)
@end lisp

@vindex gnus-summary-same-subject
@code{gnus-summary-same-subject} is a string indicating that the current
article has the same subject as the previous.  This string will be used
with those specs that require it.  The default is @code{""}.


@node Summary Buffer Lines
@subsection Summary Buffer Lines

@vindex gnus-summary-line-format
You can change the format of the lines in the summary buffer by changing
the @code{gnus-summary-line-format} variable.  It works along the same
lines as a normal @code{format} string, with some extensions
(@pxref{Formatting Variables}).

The default string is @samp{%U%R%z%I%(%[%4L: %-20,20n%]%) %s\n}.

The following format specification characters are understood:

@table @samp
@item N
Article number.
@item S
Subject string.  List identifiers stripped,
@code{gnus-list-identifies}.  @xref{Article Hiding}.
@item s
Subject if the article is the root of the thread or the previous article
had a different subject, @code{gnus-summary-same-subject} otherwise.
(@code{gnus-summary-same-subject} defaults to @code{""}.)
@item F
Full @code{From} header.
@item n
The name (from the @code{From} header).
@item f
The name, code @code{To} header or the @code{Newsgroups} header
(@pxref{To From Newsgroups}).
@item a
The name (from the @code{From} header).  This differs from the @code{n}
spec in that it uses the function designated by the
@code{gnus-extract-address-components} variable, which is slower, but
may be more thorough.
@item A
The address (from the @code{From} header).  This works the same way as
the @code{a} spec.
@item L
Number of lines in the article.
@item c
Number of characters in the article. This specifier is not supported in some
methods (like nnfolder).
@item I
Indentation based on thread level (@pxref{Customizing Threading}).
@item T
Nothing if the article is a root and lots of spaces if it isn't (it
pushes everything after it off the screen).
@item [
Opening bracket, which is normally @samp{[}, but can also be @samp{<}
for adopted articles (@pxref{Customizing Threading}).
@item ]
Closing bracket, which is normally @samp{]}, but can also be @samp{>}
for adopted articles.
@item >
One space for each thread level.
@item <
Twenty minus thread level spaces.
@item U
Unread.

@item R
This misleadingly named specifier is the @dfn{secondary mark}.  This
mark will say whether the article has been replied to, has been cached,
or has been saved.

@item i
Score as a number (@pxref{Scoring}).
@item z
@vindex gnus-summary-zcore-fuzz
Zcore, @samp{+} if above the default level and @samp{-} if below the
default level.  If the difference between
@code{gnus-summary-default-score} and the score is less than
@code{gnus-summary-zcore-fuzz}, this spec will not be used.
@item V
Total thread score.
@item x
@code{Xref}.
@item D
@code{Date}.
@item d
The @code{Date} in @code{DD-MMM} format.
@item o
The @code{Date} in @var{YYYYMMDD}@code{T}@var{HHMMSS} format.
@item M
@code{Message-ID}.
@item r
@code{References}.
@item t
Number of articles in the current sub-thread.  Using this spec will slow
down summary buffer generation somewhat.
@item e
An @samp{=} (@code{gnus-not-empty-thread-mark}) will be displayed if the
article has any children.
@item P
The line number.
@item O
Download mark.
@item u
User defined specifier.  The next character in the format string should
be a letter.  Gnus will call the function
@code{gnus-user-format-function-}@samp{X}, where @samp{X} is the letter
following @samp{%u}.  The function will be passed the current header as
argument.  The function should return a string, which will be inserted
into the summary just like information from any other summary specifier.
@end table

The @samp{%U} (status), @samp{%R} (replied) and @samp{%z} (zcore) specs
have to be handled with care.  For reasons of efficiency, Gnus will
compute what column these characters will end up in, and ``hard-code''
that.  This means that it is invalid to have these specs after a
variable-length spec.  Well, you might not be arrested, but your summary
buffer will look strange, which is bad enough.

The smart choice is to have these specs as far to the left as possible.
(Isn't that the case with everything, though?  But I digress.)

This restriction may disappear in later versions of Gnus.


@node To From Newsgroups
@subsection To From Newsgroups
@cindex To
@cindex Newsgroups

In some groups (particularly in archive groups), the @code{From} header
isn't very interesting, since all the articles there are written by
you.  To display the information in the @code{To} or @code{Newsgroups}
headers instead, you need to decide three things: What information to
gather; where to display it; and when to display it.

@enumerate
@item
@vindex gnus-extra-headers
The reading of extra header information is controlled by the
@code{gnus-extra-headers}.  This is a list of header symbols.  For
instance:

@lisp
(setq gnus-extra-headers
      '(To Newsgroups X-Newsreader))
@end lisp

This will result in Gnus trying to obtain these three headers, and
storing it in header structures for later easy retrieval.

@item
@findex gnus-extra-header
The value of these extra headers can be accessed via the
@code{gnus-extra-header} function.  Here's a format line spec that will
access the @code{X-Newsreader} header:

@example
"%~(form (gnus-extra-header 'X-Newsreader))@@"
@end example

@item
@vindex gnus-ignored-from-addresses
The @code{gnus-ignored-from-addresses} variable says when the @samp{%f}
summary line spec returns the @code{To}, @code{Newsreader} or
@code{From} header.  If this regexp matches the contents of the
@code{From} header, the value of the @code{To} or @code{Newsreader}
headers are used instead.

@end enumerate

@vindex nnmail-extra-headers
A related variable is @code{nnmail-extra-headers}, which controls when
to include extra headers when generating overview (@sc{nov}) files.  If
you have old overview files, you should regenerate them after changing
this variable.

@vindex gnus-summary-line-format
You also have to instruct Gnus to display the data by changing the
@code{%n} spec to the @code{%f} spec in the
@code{gnus-summary-line-format} variable.

In summary, you'd typically do something like the following:

@lisp
(setq gnus-extra-headers
      '(To Newsgroups))
(setq nnmail-extra-headers gnus-extra-headers)
(setq gnus-summary-line-format
      "%U%R%z%I%(%[%4L: %-20,20f%]%) %s\n")
(setq gnus-ignored-from-addresses
      "Your Name Here")
@end lisp

Now, this is mostly useful for mail groups, where you have control over
the @sc{nov} files that are created.  However, if you can persuade your
nntp admin to add:

@example
Newsgroups:full
@end example

to the end of her @file{overview.fmt} file, then you can use that just
as you would the extra headers from the mail groups.


@node Summary Buffer Mode Line
@subsection Summary Buffer Mode Line

@vindex gnus-summary-mode-line-format
You can also change the format of the summary mode bar (@pxref{Mode Line
Formatting}).  Set @code{gnus-summary-mode-line-format} to whatever you
like.  The default is @samp{Gnus: %%b [%A] %Z}.

Here are the elements you can play with:

@table @samp
@item G
Group name.
@item p
Unprefixed group name.
@item A
Current article number.
@item z
Current article score.
@item V
Gnus version.
@item U
Number of unread articles in this group.
@item e
Number of unread articles in this group that aren't displayed in the
summary buffer.
@item Z
A string with the number of unread and unselected articles represented
either as @samp{<%U(+%e) more>} if there are both unread and unselected
articles, and just as @samp{<%U more>} if there are just unread articles
and no unselected ones.
@item g
Shortish group name.  For instance, @samp{rec.arts.anime} will be
shortened to @samp{r.a.anime}.
@item S
Subject of the current article.
@item u
User-defined spec (@pxref{User-Defined Specs}).
@item s
Name of the current score file (@pxref{Scoring}).
@item d
Number of dormant articles (@pxref{Unread Articles}).
@item t
Number of ticked articles (@pxref{Unread Articles}).
@item r
Number of articles that have been marked as read in this session.
@item E
Number of articles expunged by the score files.
@end table


@node Summary Highlighting
@subsection Summary Highlighting

@table @code

@item gnus-visual-mark-article-hook
@vindex gnus-visual-mark-article-hook
This hook is run after selecting an article.  It is meant to be used for
highlighting the article in some way.  It is not run if
@code{gnus-visual} is @code{nil}.

@item gnus-summary-update-hook
@vindex gnus-summary-update-hook
This hook is called when a summary line is changed.  It is not run if
@code{gnus-visual} is @code{nil}.

@item gnus-summary-selected-face
@vindex gnus-summary-selected-face
This is the face (or @dfn{font} as some people call it) used to
highlight the current article in the summary buffer.

@item gnus-summary-highlight
@vindex gnus-summary-highlight
Summary lines are highlighted according to this variable, which is a
list where the elements are of the format @code{(@var{form}
. @var{face})}.  If you would, for instance, like ticked articles to be
italic and high-scored articles to be bold, you could set this variable
to something like
@lisp
(((eq mark gnus-ticked-mark) . italic)
 ((> score default) . bold))
@end lisp
As you may have guessed, if @var{form} returns a non-@code{nil} value,
@var{face} will be applied to the line.
@end table


@node Summary Maneuvering
@section Summary Maneuvering
@cindex summary movement

All the straight movement commands understand the numeric prefix and
behave pretty much as you'd expect.

None of these commands select articles.

@table @kbd
@item G M-n
@itemx M-n
@kindex M-n (Summary)
@kindex G M-n (Summary)
@findex gnus-summary-next-unread-subject
Go to the next summary line of an unread article
(@code{gnus-summary-next-unread-subject}).

@item G M-p
@itemx M-p
@kindex M-p (Summary)
@kindex G M-p (Summary)
@findex gnus-summary-prev-unread-subject
Go to the previous summary line of an unread article
(@code{gnus-summary-prev-unread-subject}).

@item G j
@itemx j
@kindex j (Summary)
@kindex G j (Summary)
@findex gnus-summary-goto-article
Ask for an article number or @code{Message-ID}, and then go to that
article (@code{gnus-summary-goto-article}).

@item G g
@kindex G g (Summary)
@findex gnus-summary-goto-subject
Ask for an article number and then go to the summary line of that article
without displaying the article (@code{gnus-summary-goto-subject}).
@end table

If Gnus asks you to press a key to confirm going to the next group, you
can use the @kbd{C-n} and @kbd{C-p} keys to move around the group
buffer, searching for the next group to read without actually returning
to the group buffer.

Variables related to summary movement:

@table @code

@vindex gnus-auto-select-next
@item gnus-auto-select-next
If you issue one of the movement commands (like @kbd{n}) and there are
no more unread articles after the current one, Gnus will offer to go to
the next group.  If this variable is @code{t} and the next group is
empty, Gnus will exit summary mode and return to the group buffer.  If
this variable is neither @code{t} nor @code{nil}, Gnus will select the
next group, no matter whether it has any unread articles or not.  As a
special case, if this variable is @code{quietly}, Gnus will select the
next group without asking for confirmation.  If this variable is
@code{almost-quietly}, the same will happen only if you are located on
the last article in the group.  Finally, if this variable is
@code{slightly-quietly}, the @kbd{Z n} command will go to the next group
without confirmation.  Also @pxref{Group Levels}.

@item gnus-auto-select-same
@vindex gnus-auto-select-same
If non-@code{nil}, all the movement commands will try to go to the next
article with the same subject as the current.  (@dfn{Same} here might
mean @dfn{roughly equal}.  See @code{gnus-summary-gather-subject-limit}
for details (@pxref{Customizing Threading}).)  If there are no more
articles with the same subject, go to the first unread article.

This variable is not particularly useful if you use a threaded display.

@item gnus-summary-check-current
@vindex gnus-summary-check-current
If non-@code{nil}, all the ``unread'' movement commands will not proceed
to the next (or previous) article if the current article is unread.
Instead, they will choose the current article.

@item gnus-auto-center-summary
@vindex gnus-auto-center-summary
If non-@code{nil}, Gnus will keep the point in the summary buffer
centered at all times.  This makes things quite tidy, but if you have a
slow network connection, or simply do not like this un-Emacsism, you can
set this variable to @code{nil} to get the normal Emacs scrolling
action.  This will also inhibit horizontal re-centering of the summary
buffer, which might make it more inconvenient to read extremely long
threads.

This variable can also be a number.  In that case, center the window at
the given number of lines from the top.

@end table


@node Choosing Articles
@section Choosing Articles
@cindex selecting articles

@menu
* Choosing Commands::        Commands for choosing articles.
* Choosing Variables::       Variables that influence these commands.
@end menu


@node Choosing Commands
@subsection Choosing Commands

None of the following movement commands understand the numeric prefix,
and they all select and display an article.

@table @kbd
@item SPACE
@kindex SPACE (Summary)
@findex gnus-summary-next-page
Select the current article, or, if that one's read already, the next
unread article (@code{gnus-summary-next-page}).

@item G n
@itemx n
@kindex n (Summary)
@kindex G n (Summary)
@findex gnus-summary-next-unread-article
@c @icon{gnus-summary-next-unread}
Go to next unread article (@code{gnus-summary-next-unread-article}).

@item G p
@itemx p
@kindex p (Summary)
@findex gnus-summary-prev-unread-article
@c @icon{gnus-summary-prev-unread}
Go to previous unread article (@code{gnus-summary-prev-unread-article}).

@item G N
@itemx N
@kindex N (Summary)
@kindex G N (Summary)
@findex gnus-summary-next-article
Go to the next article (@code{gnus-summary-next-article}).

@item G P
@itemx P
@kindex P (Summary)
@kindex G P (Summary)
@findex gnus-summary-prev-article
Go to the previous article (@code{gnus-summary-prev-article}).

@item G C-n
@kindex G C-n (Summary)
@findex gnus-summary-next-same-subject
Go to the next article with the same subject
(@code{gnus-summary-next-same-subject}).

@item G C-p
@kindex G C-p (Summary)
@findex gnus-summary-prev-same-subject
Go to the previous article with the same subject
(@code{gnus-summary-prev-same-subject}).

@item G f
@itemx .
@kindex G f  (Summary)
@kindex .  (Summary)
@findex gnus-summary-first-unread-article
Go to the first unread article
(@code{gnus-summary-first-unread-article}).

@item G b
@itemx ,
@kindex G b (Summary)
@kindex , (Summary)
@findex gnus-summary-best-unread-article
Go to the article with the highest score
(@code{gnus-summary-best-unread-article}).

@item G l
@itemx l
@kindex l (Summary)
@kindex G l (Summary)
@findex gnus-summary-goto-last-article
Go to the previous article read (@code{gnus-summary-goto-last-article}).

@item G o
@kindex G o (Summary)
@findex gnus-summary-pop-article
@cindex history
@cindex article history
Pop an article off the summary history and go to this article
(@code{gnus-summary-pop-article}).  This command differs from the
command above in that you can pop as many previous articles off the
history as you like, while @kbd{l} toggles the two last read articles.
For a somewhat related issue (if you use these commands a lot),
@pxref{Article Backlog}.
@end table


@node Choosing Variables
@subsection Choosing Variables

Some variables relevant for moving and selecting articles:

@table @code
@item gnus-auto-extend-newsgroup
@vindex gnus-auto-extend-newsgroup
All the movement commands will try to go to the previous (or next)
article, even if that article isn't displayed in the Summary buffer if
this variable is non-@code{nil}.  Gnus will then fetch the article from
the server and display it in the article buffer.

@item gnus-select-article-hook
@vindex gnus-select-article-hook
This hook is called whenever an article is selected.  By default it
exposes any threads hidden under the selected article.

@item gnus-mark-article-hook
@vindex gnus-mark-article-hook
@findex gnus-summary-mark-unread-as-read
@findex gnus-summary-mark-read-and-unread-as-read
@findex gnus-unread-mark
This hook is called whenever an article is selected.  It is intended to
be used for marking articles as read.  The default value is
@code{gnus-summary-mark-read-and-unread-as-read}, and will change the
mark of almost any article you read to @code{gnus-unread-mark}.  The
only articles not affected by this function are ticked, dormant, and
expirable articles.  If you'd instead like to just have unread articles
marked as read, you can use @code{gnus-summary-mark-unread-as-read}
instead.  It will leave marks like @code{gnus-low-score-mark},
@code{gnus-del-mark} (and so on) alone.

@end table


@node Paging the Article
@section Scrolling the Article
@cindex article scrolling

@table @kbd

@item SPACE
@kindex SPACE (Summary)
@findex gnus-summary-next-page
Pressing @kbd{SPACE} will scroll the current article forward one page,
or, if you have come to the end of the current article, will choose the
next article (@code{gnus-summary-next-page}).

@item DEL
@kindex DEL (Summary)
@findex gnus-summary-prev-page
Scroll the current article back one page (@code{gnus-summary-prev-page}).

@item RET
@kindex RET (Summary)
@findex gnus-summary-scroll-up
Scroll the current article one line forward
(@code{gnus-summary-scroll-up}).

@item M-RET
@kindex M-RET (Summary)
@findex gnus-summary-scroll-down
Scroll the current article one line backward
(@code{gnus-summary-scroll-down}).

@item A g
@itemx g
@kindex A g (Summary)
@kindex g (Summary)
@findex gnus-summary-show-article
@vindex gnus-summary-show-article-charset-alist
(Re)fetch the current article (@code{gnus-summary-show-article}).  If
given a prefix, fetch the current article, but don't run any of the
article treatment functions.  This will give you a ``raw'' article, just
the way it came from the server.

If given a numerical prefix, you can do semi-manual charset stuff.
@kbd{C-u 0 g cn-gb-2312 RET} will decode the message as if it were
encoded in the @code{cn-gb-2312} charset.  If you have

@lisp
(setq gnus-summary-show-article-charset-alist 
      '((1 . cn-gb-2312) 
        (2 . big5)))
@end lisp

then you can say @kbd{C-u 1 g} to get the same effect.

@item A <
@itemx <
@kindex < (Summary)
@kindex A < (Summary)
@findex gnus-summary-beginning-of-article
Scroll to the beginning of the article
(@code{gnus-summary-beginning-of-article}).

@item A >
@itemx >
@kindex > (Summary)
@kindex A > (Summary)
@findex gnus-summary-end-of-article
Scroll to the end of the article (@code{gnus-summary-end-of-article}).

@item A s
@itemx s
@kindex A s (Summary)
@kindex s (Summary)
@findex gnus-summary-isearch-article
Perform an isearch in the article buffer
(@code{gnus-summary-isearch-article}).

@item h
@kindex h (Summary)
@findex gnus-summary-select-article-buffer
Select the article buffer (@code{gnus-summary-select-article-buffer}).

@end table


@node Reply Followup and Post
@section Reply, Followup and Post

@menu
* Summary Mail Commands::       Sending mail.
* Summary Post Commands::       Sending news.
* Summary Message Commands::    Other Message-related commands.
* Canceling and Superseding::   ``Whoops, I shouldn't have called him that.''
@end menu


@node Summary Mail Commands
@subsection Summary Mail Commands
@cindex mail
@cindex composing mail

Commands for composing a mail message:

@table @kbd

@item S r
@itemx r
@kindex S r (Summary)
@kindex r (Summary)
@findex gnus-summary-reply
@c @icon{gnus-summary-mail-reply}
@c @icon{gnus-summary-reply}
Mail a reply to the author of the current article
(@code{gnus-summary-reply}).

@item S R
@itemx R
@kindex R (Summary)
@kindex S R (Summary)
@findex gnus-summary-reply-with-original
@c @icon{gnus-summary-reply-with-original}
Mail a reply to the author of the current article and include the
original message (@code{gnus-summary-reply-with-original}).  This
command uses the process/prefix convention.

@item S w
@kindex S w (Summary)
@findex gnus-summary-wide-reply
Mail a wide reply to the author of the current article
(@code{gnus-summary-wide-reply}).  A @dfn{wide reply} is a reply that
goes out to all people listed in the @code{To}, @code{From} (or
@code{Reply-to}) and @code{Cc} headers.

@item S W
@kindex S W (Summary)
@findex gnus-summary-wide-reply-with-original
Mail a wide reply to the current article and include the original
message (@code{gnus-summary-wide-reply-with-original}).  This command uses
the process/prefix convention.

@item S o m
@itemx C-c C-f
@kindex S o m (Summary)
@kindex C-c C-f (Summary)
@findex gnus-summary-mail-forward
@c @icon{gnus-summary-mail-forward}
Forward the current article to some other person
(@code{gnus-summary-mail-forward}).  If no prefix is given, the message
is forwarded according to the value of (@code{message-forward-as-mime})
and (@code{message-forward-show-mml}); if the prefix is 1, decode the
message and forward directly inline; if the prefix is 2, foward message
as an rfc822 MIME section; if the prefix is 3, decode message and
forward as an rfc822 MIME section; if the prefix is 4, foward message
directly inline; otherwise, the message is forwarded as no prefix given
but use the flipped value of (@code{message-forward-as-mime}).  By
default, the message is decoded and forwarded as an rfc822 MIME section.

@item S m
@itemx m
@kindex m (Summary)
@kindex S m (Summary)
@findex gnus-summary-mail-other-window
@c @icon{gnus-summary-mail-originate}
Send a mail to some other person
(@code{gnus-summary-mail-other-window}).

@item S D b
@kindex S D b (Summary)
@findex gnus-summary-resend-bounced-mail
@cindex bouncing mail
If you have sent a mail, but the mail was bounced back to you for some
reason (wrong address, transient failure), you can use this command to
resend that bounced mail (@code{gnus-summary-resend-bounced-mail}).  You
will be popped into a mail buffer where you can edit the headers before
sending the mail off again.  If you give a prefix to this command, and
the bounced mail is a reply to some other mail, Gnus will try to fetch
that mail and display it for easy perusal of its headers.  This might
very well fail, though.

@item S D r
@kindex S D r (Summary)
@findex gnus-summary-resend-message
Not to be confused with the previous command,
@code{gnus-summary-resend-message} will prompt you for an address to
send the current message off to, and then send it to that place.  The
headers of the message won't be altered---but lots of headers that say
@code{Resent-To}, @code{Resent-From} and so on will be added.  This
means that you actually send a mail to someone that has a @code{To}
header that (probably) points to yourself.  This will confuse people.
So, natcherly you'll only do that if you're really eVIl.

This command is mainly used if you have several accounts and want to
ship a mail to a different account of yours.  (If you're both
@code{root} and @code{postmaster} and get a mail for @code{postmaster}
to the @code{root} account, you may want to resend it to
@code{postmaster}.  Ordnung muß sein!

This command understands the process/prefix convention
(@pxref{Process/Prefix}).

@item S O m
@kindex S O m (Summary)
@findex gnus-uu-digest-mail-forward
Digest the current series (@pxref{Decoding Articles}) and forward the
result using mail (@code{gnus-uu-digest-mail-forward}).  This command
uses the process/prefix convention (@pxref{Process/Prefix}).

@item S M-c
@kindex S M-c (Summary)
@findex gnus-summary-mail-crosspost-complaint
@cindex crossposting
@cindex excessive crossposting
Send a complaint about excessive crossposting to the author of the
current article (@code{gnus-summary-mail-crosspost-complaint}).

@findex gnus-crosspost-complaint
This command is provided as a way to fight back against the current
crossposting pandemic that's sweeping Usenet.  It will compose a reply
using the @code{gnus-crosspost-complaint} variable as a preamble.  This
command understands the process/prefix convention
(@pxref{Process/Prefix}) and will prompt you before sending each mail.

@end table

Also @pxref{(message)Header Commands} for more information.


@node Summary Post Commands
@subsection Summary Post Commands
@cindex post
@cindex composing news

Commands for posting a news article:

@table @kbd
@item S p
@itemx a
@kindex a (Summary)
@kindex S p (Summary)
@findex gnus-summary-post-news
@c @icon{gnus-summary-post-news}
Post an article to the current group
(@code{gnus-summary-post-news}).

@item S f
@itemx f
@kindex f (Summary)
@kindex S f (Summary)
@findex gnus-summary-followup
@c @icon{gnus-summary-followup}
Post a followup to the current article (@code{gnus-summary-followup}).

@item S F
@itemx F
@kindex S F (Summary)
@kindex F (Summary)
@c @icon{gnus-summary-followup-with-original}
@findex gnus-summary-followup-with-original
Post a followup to the current article and include the original message
(@code{gnus-summary-followup-with-original}).   This command uses the
process/prefix convention.

@item S n
@kindex S n (Summary)
@findex gnus-summary-followup-to-mail
Post a followup to the current article via news, even if you got the
message through mail (@code{gnus-summary-followup-to-mail}).

@item S N
@kindex S N (Summary)
@findex gnus-summary-followup-to-mail-with-original
Post a followup to the current article via news, even if you got the
message through mail and include the original message
(@code{gnus-summary-followup-to-mail-with-original}).  This command uses
the process/prefix convention.

@item S o p
@kindex S o p (Summary)
@findex gnus-summary-post-forward
Forward the current article to a newsgroup
(@code{gnus-summary-post-forward}).  
 If no prefix is given, the message is forwarded according to the value
of (@code{message-forward-as-mime}) and
(@code{message-forward-show-mml}); if the prefix is 1, decode the
message and forward directly inline; if the prefix is 2, foward message
as an rfc822 MIME section; if the prefix is 3, decode message and
forward as an rfc822 MIME section; if the prefix is 4, foward message
directly inline; otherwise, the message is forwarded as no prefix given
but use the flipped value of (@code{message-forward-as-mime}).  By
default, the message is decoded and forwarded as an rfc822 MIME section.

@item S O p
@kindex S O p (Summary)
@findex gnus-uu-digest-post-forward
@cindex digests
@cindex making digests
Digest the current series and forward the result to a newsgroup
(@code{gnus-uu-digest-mail-forward}).  This command uses the
process/prefix convention.

@item S u
@kindex S u (Summary)
@findex gnus-uu-post-news
@c @icon{gnus-uu-post-news}
Uuencode a file, split it into parts, and post it as a series
(@code{gnus-uu-post-news}).  (@pxref{Uuencoding and Posting}).
@end table

Also @pxref{(message)Header Commands} for more information.


@node Summary Message Commands
@subsection Summary Message Commands

@table @kbd
@item S y
@kindex S y (Summary)
@findex gnus-summary-yank-message
Yank the current article into an already existing Message composition
buffer (@code{gnus-summary-yank-message}).  This command prompts for
what message buffer you want to yank into, and understands the
process/prefix convention (@pxref{Process/Prefix}).

@end table


@node Canceling and Superseding
@subsection Canceling Articles
@cindex canceling articles
@cindex superseding articles

Have you ever written something, and then decided that you really,
really, really wish you hadn't posted that?

Well, you can't cancel mail, but you can cancel posts.

@findex gnus-summary-cancel-article
@kindex C (Summary)
@c @icon{gnus-summary-cancel-article}
Find the article you wish to cancel (you can only cancel your own
articles, so don't try any funny stuff).  Then press @kbd{C} or @kbd{S
c} (@code{gnus-summary-cancel-article}).  Your article will be
canceled---machines all over the world will be deleting your article.
This command uses the process/prefix convention (@pxref{Process/Prefix}).

Be aware, however, that not all sites honor cancels, so your article may
live on here and there, while most sites will delete the article in
question.

Gnus will use the ``current'' select method when canceling.  If you
want to use the standard posting method, use the @samp{a} symbolic
prefix (@pxref{Symbolic Prefixes}).

If you discover that you have made some mistakes and want to do some
corrections, you can post a @dfn{superseding} article that will replace
your original article.

@findex gnus-summary-supersede-article
@kindex S (Summary)
Go to the original article and press @kbd{S s}
(@code{gnus-summary-supersede-article}).  You will be put in a buffer
where you can edit the article all you want before sending it off the
usual way.

The same goes for superseding as for canceling, only more so: Some
sites do not honor superseding.  On those sites, it will appear that you
have posted almost the same article twice.

If you have just posted the article, and change your mind right away,
there is a trick you can use to cancel/supersede the article without
waiting for the article to appear on your site first.  You simply return
to the post buffer (which is called @code{*sent ...*}).  There you will
find the article you just posted, with all the headers intact.  Change
the @code{Message-ID} header to a @code{Cancel} or @code{Supersedes}
header by substituting one of those words for the word
@code{Message-ID}.  Then just press @kbd{C-c C-c} to send the article as
you would do normally.  The previous article will be
canceled/superseded.

Just remember, kids: There is no 'c' in 'supersede'.


@node Marking Articles
@section Marking Articles
@cindex article marking
@cindex article ticking
@cindex marks

There are several marks you can set on an article.

You have marks that decide the @dfn{readedness} (whoo, neato-keano
neologism ohoy!) of the article.  Alphabetic marks generally mean
@dfn{read}, while non-alphabetic characters generally mean @dfn{unread}.

In addition, you also have marks that do not affect readedness.

@menu
* Unread Articles::      Marks for unread articles.
* Read Articles::        Marks for read articles.
* Other Marks::          Marks that do not affect readedness.
@end menu

@ifinfo
There's a plethora of commands for manipulating these marks:
@end ifinfo

@menu
* Setting Marks::             How to set and remove marks.
* Generic Marking Commands::  How to customize the marking.
* Setting Process Marks::     How to mark articles for later processing.
@end menu


@node Unread Articles
@subsection Unread Articles

The following marks mark articles as (kinda) unread, in one form or
other.

@table @samp
@item !
@vindex gnus-ticked-mark
Marked as ticked (@code{gnus-ticked-mark}).

@dfn{Ticked articles} are articles that will remain visible always.  If
you see an article that you find interesting, or you want to put off
reading it, or replying to it, until sometime later, you'd typically
tick it.  However, articles can be expired, so if you want to keep an
article forever, you'll have to make it persistent (@pxref{Persistent
Articles}).

@item ?
@vindex gnus-dormant-mark
Marked as dormant (@code{gnus-dormant-mark}).

@dfn{Dormant articles} will only appear in the summary buffer if there
are followups to it.  If you want to see them even if they don't have
followups, you can use the @kbd{/ D} command (@pxref{Limiting}).

@item SPACE
@vindex gnus-unread-mark
Marked as unread (@code{gnus-unread-mark}).

@dfn{Unread articles} are articles that haven't been read at all yet.
@end table


@node Read Articles
@subsection Read Articles
@cindex expirable mark

All the following marks mark articles as read.

@table @samp

@item r
@vindex gnus-del-mark
These are articles that the user has marked as read with the @kbd{d}
command manually, more or less (@code{gnus-del-mark}).

@item R
@vindex gnus-read-mark
Articles that have actually been read (@code{gnus-read-mark}).

@item O
@vindex gnus-ancient-mark
Articles that were marked as read in previous sessions and are now
@dfn{old} (@code{gnus-ancient-mark}).

@item K
@vindex gnus-killed-mark
Marked as killed (@code{gnus-killed-mark}).

@item X
@vindex gnus-kill-file-mark
Marked as killed by kill files (@code{gnus-kill-file-mark}).

@item Y
@vindex gnus-low-score-mark
Marked as read by having too low a score (@code{gnus-low-score-mark}).

@item C
@vindex gnus-catchup-mark
Marked as read by a catchup (@code{gnus-catchup-mark}).

@item G
@vindex gnus-canceled-mark
Canceled article (@code{gnus-canceled-mark})

@item F
@vindex gnus-souped-mark
@sc{soup}ed article (@code{gnus-souped-mark}).  @xref{SOUP}.

@item Q
@vindex gnus-sparse-mark
Sparsely reffed article (@code{gnus-sparse-mark}).  @xref{Customizing
Threading}.

@item M
@vindex gnus-duplicate-mark
Article marked as read by duplicate suppression
(@code{gnus-duplicated-mark}).  @xref{Duplicate Suppression}.

@end table

All these marks just mean that the article is marked as read, really.
They are interpreted differently when doing adaptive scoring, though.

One more special mark, though:

@table @samp
@item E
@vindex gnus-expirable-mark
Marked as expirable (@code{gnus-expirable-mark}).

Marking articles as @dfn{expirable} (or have them marked as such
automatically) doesn't make much sense in normal groups---a user doesn't
control expiring of news articles, but in mail groups, for instance,
articles marked as @dfn{expirable} can be deleted by Gnus at
any time.
@end table


@node Other Marks
@subsection Other Marks
@cindex process mark
@cindex bookmarks

There are some marks that have nothing to do with whether the article is
read or not.

@itemize @bullet

@item
You can set a bookmark in the current article.  Say you are reading a
long thesis on cats' urinary tracts, and have to go home for dinner
before you've finished reading the thesis.  You can then set a bookmark
in the article, and Gnus will jump to this bookmark the next time it
encounters the article.  @xref{Setting Marks}.

@item
@vindex gnus-replied-mark
All articles that you have replied to or made a followup to (i.e., have
answered) will be marked with an @samp{A} in the second column
(@code{gnus-replied-mark}).

@item
@vindex gnus-cached-mark
Articles stored in the article cache will be marked with an @samp{*} in
the second column (@code{gnus-cached-mark}).  @xref{Article Caching}.

@item
@vindex gnus-saved-mark
Articles ``saved'' (in some manner or other; not necessarily
religiously) are marked with an @samp{S} in the second column
(@code{gnus-saved-mark}).

@item
@vindex gnus-not-empty-thread-mark
@vindex gnus-empty-thread-mark
If the @samp{%e} spec is used, the presence of threads or not will be
marked with @code{gnus-not-empty-thread-mark} and
@code{gnus-empty-thread-mark} in the third column, respectively.

@item
@vindex gnus-process-mark
Finally we have the @dfn{process mark} (@code{gnus-process-mark}).  A
variety of commands react to the presence of the process mark.  For
instance, @kbd{X u} (@code{gnus-uu-decode-uu}) will uudecode and view
all articles that have been marked with the process mark.  Articles
marked with the process mark have a @samp{#} in the second column.

@end itemize

You might have noticed that most of these ``non-readedness'' marks
appear in the second column by default.  So if you have a cached, saved,
replied article that you have process-marked, what will that look like?

Nothing much.  The precedence rules go as follows: process -> cache ->
replied -> saved.  So if the article is in the cache and is replied,
you'll only see the cache mark and not the replied mark.


@node Setting Marks
@subsection Setting Marks
@cindex setting marks

All the marking commands understand the numeric prefix.

@table @kbd
@item M c
@itemx M-u
@kindex M c (Summary)
@kindex M-u (Summary)
@findex gnus-summary-clear-mark-forward
@cindex mark as unread
Clear all readedness-marks from the current article
(@code{gnus-summary-clear-mark-forward}).  In other words, mark the
article as unread.

@item M t
@itemx !
@kindex ! (Summary)
@kindex M t (Summary)
@findex gnus-summary-tick-article-forward
Tick the current article (@code{gnus-summary-tick-article-forward}).
@xref{Article Caching}.

@item M ?
@itemx ?
@kindex ? (Summary)
@kindex M ? (Summary)
@findex gnus-summary-mark-as-dormant
Mark the current article as dormant
(@code{gnus-summary-mark-as-dormant}).  @xref{Article Caching}.

@item M d
@itemx d
@kindex M d (Summary)
@kindex d (Summary)
@findex gnus-summary-mark-as-read-forward
Mark the current article as read
(@code{gnus-summary-mark-as-read-forward}).

@item D
@kindex D (Summary)
@findex gnus-summary-mark-as-read-backward
Mark the current article as read and move point to the previous line
(@code{gnus-summary-mark-as-read-backward}).

@item M k
@itemx k
@kindex k (Summary)
@kindex M k (Summary)
@findex gnus-summary-kill-same-subject-and-select
Mark all articles that have the same subject as the current one as read,
and then select the next unread article
(@code{gnus-summary-kill-same-subject-and-select}).

@item M K
@itemx C-k
@kindex M K (Summary)
@kindex C-k (Summary)
@findex gnus-summary-kill-same-subject
Mark all articles that have the same subject as the current one as read
(@code{gnus-summary-kill-same-subject}).

@item M C
@kindex M C (Summary)
@findex gnus-summary-catchup
@c @icon{gnus-summary-catchup}
Mark all unread articles as read (@code{gnus-summary-catchup}).

@item M C-c
@kindex M C-c (Summary)
@findex gnus-summary-catchup-all
Mark all articles in the group as read---even the ticked and dormant
articles (@code{gnus-summary-catchup-all}).

@item M H
@kindex M H (Summary)
@findex gnus-summary-catchup-to-here
Catchup the current group to point
(@code{gnus-summary-catchup-to-here}).

@item C-w
@kindex C-w (Summary)
@findex gnus-summary-mark-region-as-read
Mark all articles between point and mark as read
(@code{gnus-summary-mark-region-as-read}).

@item M V k
@kindex M V k (Summary)
@findex gnus-summary-kill-below
Kill all articles with scores below the default score (or below the
numeric prefix) (@code{gnus-summary-kill-below}).

@item M e
@itemx E
@kindex M e (Summary)
@kindex E (Summary)
@findex gnus-summary-mark-as-expirable
Mark the current article as expirable
(@code{gnus-summary-mark-as-expirable}).

@item M b
@kindex M b (Summary)
@findex gnus-summary-set-bookmark
Set a bookmark in the current article
(@code{gnus-summary-set-bookmark}).

@item M B
@kindex M B (Summary)
@findex gnus-summary-remove-bookmark
Remove the bookmark from the current article
(@code{gnus-summary-remove-bookmark}).

@item M V c
@kindex M V c (Summary)
@findex gnus-summary-clear-above
Clear all marks from articles with scores over the default score (or
over the numeric prefix) (@code{gnus-summary-clear-above}).

@item M V u
@kindex M V u (Summary)
@findex gnus-summary-tick-above
Tick all articles with scores over the default score (or over the
numeric prefix) (@code{gnus-summary-tick-above}).

@item M V m
@kindex M V m (Summary)
@findex gnus-summary-mark-above
Prompt for a mark, and mark all articles with scores over the default
score (or over the numeric prefix) with this mark
(@code{gnus-summary-clear-above}).
@end table

@vindex gnus-summary-goto-unread
The @code{gnus-summary-goto-unread} variable controls what action should
be taken after setting a mark.  If non-@code{nil}, point will move to
the next/previous unread article.  If @code{nil}, point will just move
one line up or down.  As a special case, if this variable is
@code{never}, all the marking commands as well as other commands (like
@kbd{SPACE}) will move to the next article, whether it is unread or not.
The default is @code{t}.


@node Generic Marking Commands
@subsection Generic Marking Commands

Some people would like the command that ticks an article (@kbd{!}) go to
the next article.  Others would like it to go to the next unread
article.  Yet others would like it to stay on the current article.  And
even though I haven't heard of anybody wanting it to go to the
previous (unread) article, I'm sure there are people that want that as
well.

Multiply these five behaviours with five different marking commands, and
you get a potentially complex set of variable to control what each
command should do.

To sidestep that mess, Gnus provides commands that do all these
different things.  They can be found on the @kbd{M M} map in the summary
buffer.  Type @kbd{M M C-h} to see them all---there are too many of them
to list in this manual.

While you can use these commands directly, most users would prefer
altering the summary mode keymap.  For instance, if you would like the
@kbd{!} command to go to the next article instead of the next unread
article, you could say something like:

@lisp
(add-hook 'gnus-summary-mode-hook 'my-alter-summary-map)
(defun my-alter-summary-map ()
  (local-set-key "!" 'gnus-summary-put-mark-as-ticked-next))
@end lisp

or

@lisp
(defun my-alter-summary-map ()
  (local-set-key "!" "MM!n"))
@end lisp


@node Setting Process Marks
@subsection Setting Process Marks
@cindex setting process marks

@table @kbd

@item M P p
@itemx #
@kindex # (Summary)
@kindex M P p (Summary)
@findex gnus-summary-mark-as-processable
Mark the current article with the process mark
(@code{gnus-summary-mark-as-processable}).
@findex gnus-summary-unmark-as-processable

@item M P u
@itemx M-#
@kindex M P u (Summary)
@kindex M-# (Summary)
Remove the process mark, if any, from the current article
(@code{gnus-summary-unmark-as-processable}).

@item M P U
@kindex M P U (Summary)
@findex gnus-summary-unmark-all-processable
Remove the process mark from all articles
(@code{gnus-summary-unmark-all-processable}).

@item M P i
@kindex M P i (Summary)
@findex gnus-uu-invert-processable
Invert the list of process marked articles
(@code{gnus-uu-invert-processable}).

@item M P R
@kindex M P R (Summary)
@findex gnus-uu-mark-by-regexp
Mark articles that have a @code{Subject} header that matches a regular
expression (@code{gnus-uu-mark-by-regexp}).

@item M P G
@kindex M P G (Summary)
@findex gnus-uu-unmark-by-regexp
Unmark articles that have a @code{Subject} header that matches a regular
expression (@code{gnus-uu-unmark-by-regexp}).

@item M P r
@kindex M P r (Summary)
@findex gnus-uu-mark-region
Mark articles in region (@code{gnus-uu-mark-region}).

@item M P t
@kindex M P t (Summary)
@findex gnus-uu-mark-thread
Mark all articles in the current (sub)thread
(@code{gnus-uu-mark-thread}).

@item M P T
@kindex M P T (Summary)
@findex gnus-uu-unmark-thread
Unmark all articles in the current (sub)thread
(@code{gnus-uu-unmark-thread}).

@item M P v
@kindex M P v (Summary)
@findex gnus-uu-mark-over
Mark all articles that have a score above the prefix argument
(@code{gnus-uu-mark-over}).

@item M P s
@kindex M P s (Summary)
@findex gnus-uu-mark-series
Mark all articles in the current series (@code{gnus-uu-mark-series}).

@item M P S
@kindex M P S (Summary)
@findex gnus-uu-mark-sparse
Mark all series that have already had some articles marked
(@code{gnus-uu-mark-sparse}).

@item M P a
@kindex M P a (Summary)
@findex gnus-uu-mark-all
Mark all articles in series order (@code{gnus-uu-mark-series}).

@item M P b
@kindex M P b (Summary)
@findex gnus-uu-mark-buffer
Mark all articles in the buffer in the order they appear
(@code{gnus-uu-mark-buffer}).

@item M P k
@kindex M P k (Summary)
@findex gnus-summary-kill-process-mark
Push the current process mark set onto the stack and unmark all articles
(@code{gnus-summary-kill-process-mark}).

@item M P y
@kindex M P y (Summary)
@findex gnus-summary-yank-process-mark
Pop the previous process mark set from the stack and restore it
(@code{gnus-summary-yank-process-mark}).

@item M P w
@kindex M P w (Summary)
@findex gnus-summary-save-process-mark
Push the current process mark set onto the stack
(@code{gnus-summary-save-process-mark}).

@end table

Also see the @kbd{&} command in @pxref{Searching for Articles} for how to
set process marks based on article body contents.


@node Limiting
@section Limiting
@cindex limiting

It can be convenient to limit the summary buffer to just show some
subset of the articles currently in the group.  The effect most limit
commands have is to remove a few (or many) articles from the summary
buffer.

All limiting commands work on subsets of the articles already fetched
from the servers.  None of these commands query the server for
additional articles.

@table @kbd

@item / /
@itemx / s
@kindex / / (Summary)
@findex gnus-summary-limit-to-subject
Limit the summary buffer to articles that match some subject
(@code{gnus-summary-limit-to-subject}).

@item / a
@kindex / a (Summary)
@findex gnus-summary-limit-to-author
Limit the summary buffer to articles that match some author
(@code{gnus-summary-limit-to-author}).

@item / x
@kindex / x (Summary)
@findex gnus-summary-limit-to-extra
Limit the summary buffer to articles that match one of the ``extra''
headers (@pxref{To From Newsgroups})
(@code{gnus-summary-limit-to-extra}).

@item / u
@itemx x
@kindex / u (Summary)
@kindex x (Summary)
@findex gnus-summary-limit-to-unread
Limit the summary buffer to articles not marked as read
(@code{gnus-summary-limit-to-unread}).  If given a prefix, limit the
buffer to articles strictly unread.  This means that ticked and
dormant articles will also be excluded.

@item / m
@kindex / m (Summary)
@findex gnus-summary-limit-to-marks
Ask for a mark and then limit to all articles that have been marked
with that mark (@code{gnus-summary-limit-to-marks}).

@item / t
@kindex / t (Summary)
@findex gnus-summary-limit-to-age
Ask for a number and then limit the summary buffer to articles older than (or equal to) that number of days
(@code{gnus-summary-limit-to-age}).  If given a prefix, limit to
articles younger than that number of days.

@item / n
@kindex / n (Summary)
@findex gnus-summary-limit-to-articles
Limit the summary buffer to the current article
(@code{gnus-summary-limit-to-articles}).  Uses the process/prefix
convention (@pxref{Process/Prefix}).

@item / w
@kindex / w (Summary)
@findex gnus-summary-pop-limit
Pop the previous limit off the stack and restore it
(@code{gnus-summary-pop-limit}).  If given a prefix, pop all limits off
the stack.

@item / v
@kindex / v (Summary)
@findex gnus-summary-limit-to-score
Limit the summary buffer to articles that have a score at or above some
score (@code{gnus-summary-limit-to-score}).

@item / E
@itemx M S
@kindex M S (Summary)
@kindex / E (Summary)
@findex gnus-summary-limit-include-expunged
Include all expunged articles in the limit
(@code{gnus-summary-limit-include-expunged}).

@item / D
@kindex / D (Summary)
@findex gnus-summary-limit-include-dormant
Include all dormant articles in the limit
(@code{gnus-summary-limit-include-dormant}).

@item / *
@kindex / * (Summary)
@findex gnus-summary-limit-include-cached
Include all cached articles in the limit
(@code{gnus-summary-limit-include-cached}).

@item / d
@kindex / d (Summary)
@findex gnus-summary-limit-exclude-dormant
Exclude all dormant articles from the limit
(@code{gnus-summary-limit-exclude-dormant}).

@item / M
@kindex / M (Summary)
@findex gnus-summary-limit-exclude-marks
Exclude all marked articles (@code{gnus-summary-limit-exclude-marks}).

@item / T
@kindex / T (Summary)
@findex gnus-summary-limit-include-thread
Include all the articles in the current thread in the limit.

@item / c
@kindex / c (Summary)
@findex gnus-summary-limit-exclude-childless-dormant
Exclude all dormant articles that have no children from the limit
(@code{gnus-summary-limit-exclude-childless-dormant}).

@item / C
@kindex / C (Summary)
@findex gnus-summary-limit-mark-excluded-as-read
Mark all excluded unread articles as read
(@code{gnus-summary-limit-mark-excluded-as-read}).   If given a prefix,
also mark excluded ticked and dormant articles as read.

@end table


@node Threading
@section Threading
@cindex threading
@cindex article threading

Gnus threads articles by default.  @dfn{To thread} is to put responses
to articles directly after the articles they respond to---in a
hierarchical fashion.

Threading is done by looking at the @code{References} headers of the
articles.  In a perfect world, this would be enough to build pretty
trees, but unfortunately, the @code{References} header is often broken
or simply missing.  Weird news propagation excarcerbates the problem,
so one has to employ other heuristics to get pleasing results.  A
plethora of approaches exists, as detailed in horrible detail in
@pxref{Customizing Threading}.

First, a quick overview of the concepts:

@table @dfn
@item root
The top-most article in a thread; the first article in the thread.

@item thread
A tree-like article structure.

@item sub-thread
A small(er) section of this tree-like structure.

@item loose threads
Threads often lose their roots due to article expiry, or due to the root
already having been read in a previous session, and not displayed in the
summary buffer.  We then typically have many sub-threads that really
belong to one thread, but are without connecting roots.  These are
called loose threads.

@item thread gathering
An attempt to gather loose threads into bigger threads.

@item sparse threads
A thread where the missing articles have been ``guessed'' at, and are
displayed as empty lines in the summary buffer.

@end table


@menu
* Customizing Threading::     Variables you can change to affect the threading.
* Thread Commands::           Thread based commands in the summary buffer.
@end menu


@node Customizing Threading
@subsection Customizing Threading
@cindex customizing threading

@menu
* Loose Threads::        How Gnus gathers loose threads into bigger threads.
* Filling In Threads::   Making the threads displayed look fuller.
* More Threading::       Even more variables for fiddling with threads.
* Low-Level Threading::  You thought it was over... but you were wrong!
@end menu


@node Loose Threads
@subsubsection Loose Threads
@cindex <
@cindex >
@cindex loose threads

@table @code
@item gnus-summary-make-false-root
@vindex gnus-summary-make-false-root
If non-@code{nil}, Gnus will gather all loose subtrees into one big tree
and create a dummy root at the top.  (Wait a minute.  Root at the top?
Yup.)  Loose subtrees occur when the real root has expired, or you've
read or killed the root in a previous session.

When there is no real root of a thread, Gnus will have to fudge
something.  This variable says what fudging method Gnus should use.
There are four possible values:

@iftex
@iflatex
\gnusfigure{The Summary Buffer}{390}{
\put(0,0){\epsfig{figure=tmp/summary-adopt.ps,width=7.5cm}}
\put(445,0){\makebox(0,0)[br]{\epsfig{figure=tmp/summary-empty.ps,width=7.5cm}}}
\put(0,400){\makebox(0,0)[tl]{\epsfig{figure=tmp/summary-none.ps,width=7.5cm}}}
\put(445,400){\makebox(0,0)[tr]{\epsfig{figure=tmp/summary-dummy.ps,width=7.5cm}}}
}
@end iflatex
@end iftex

@cindex adopting articles

@table @code

@item adopt
Gnus will make the first of the orphaned articles the parent.  This
parent will adopt all the other articles.  The adopted articles will be
marked as such by pointy brackets (@samp{<>}) instead of the standard
square brackets (@samp{[]}).  This is the default method.

@item dummy
@vindex gnus-summary-dummy-line-format
Gnus will create a dummy summary line that will pretend to be the
parent.  This dummy line does not correspond to any real article, so
selecting it will just select the first real article after the dummy
article.  @code{gnus-summary-dummy-line-format} is used to specify the
format of the dummy roots.  It accepts only one format spec:  @samp{S},
which is the subject of the article.  @xref{Formatting Variables}.

@item empty
Gnus won't actually make any article the parent, but simply leave the
subject field of all orphans except the first empty.  (Actually, it will
use @code{gnus-summary-same-subject} as the subject (@pxref{Summary
Buffer Format}).)

@item none
Don't make any article parent at all.  Just gather the threads and
display them after one another.

@item nil
Don't gather loose threads.
@end table

@item gnus-summary-gather-subject-limit
@vindex gnus-summary-gather-subject-limit
Loose threads are gathered by comparing subjects of articles.  If this
variable is @code{nil}, Gnus requires an exact match between the
subjects of the loose threads before gathering them into one big
super-thread.  This might be too strict a requirement, what with the
presence of stupid newsreaders that chop off long subject lines.  If
you think so, set this variable to, say, 20 to require that only the
first 20 characters of the subjects have to match.  If you set this
variable to a really low number, you'll find that Gnus will gather
everything in sight into one thread, which isn't very helpful.

@cindex fuzzy article gathering
If you set this variable to the special value @code{fuzzy}, Gnus will
use a fuzzy string comparison algorithm on the subjects (@pxref{Fuzzy
Matching}).

@item gnus-simplify-subject-fuzzy-regexp
@vindex gnus-simplify-subject-fuzzy-regexp
This can either be a regular expression or list of regular expressions
that match strings that will be removed from subjects if fuzzy subject
simplification is used.

@item gnus-simplify-ignored-prefixes
@vindex gnus-simplify-ignored-prefixes
If you set @code{gnus-summary-gather-subject-limit} to something as low
as 10, you might consider setting this variable to something sensible:

@c Written by Michael Ernst <mernst@cs.rice.edu>
@lisp
(setq gnus-simplify-ignored-prefixes
      (concat
       "\\`\\[?\\("
       (mapconcat
        'identity
        '("looking"
          "wanted" "followup" "summary\\( of\\)?"
          "help" "query" "problem" "question"
          "answer" "reference" "announce"
          "How can I" "How to" "Comparison of"
          ;; ...
          )
        "\\|")
       "\\)\\s *\\("
       (mapconcat 'identity
                  '("for" "for reference" "with" "about")
                  "\\|")
       "\\)?\\]?:?[ \t]*"))
@end lisp

All words that match this regexp will be removed before comparing two
subjects.

@item gnus-simplify-subject-functions
@vindex gnus-simplify-subject-functions
If non-@code{nil}, this variable overrides
@code{gnus-summary-gather-subject-limit}.  This variable should be a
list of functions to apply to the @code{Subject} string iteratively to
arrive at the simplified version of the string.

Useful functions to put in this list include:

@table @code
@item gnus-simplify-subject-re
@findex gnus-simplify-subject-re
Strip the leading @samp{Re:}.

@item gnus-simplify-subject-fuzzy
@findex gnus-simplify-subject-fuzzy
Simplify fuzzily.

@item gnus-simplify-whitespace
@findex gnus-simplify-whitespace
Remove excessive whitespace.
@end table

You may also write your own functions, of course.


@item gnus-summary-gather-exclude-subject
@vindex gnus-summary-gather-exclude-subject
Since loose thread gathering is done on subjects only, that might lead
to many false hits, especially with certain common subjects like
@samp{} and @samp{(none)}.  To make the situation slightly better,
you can use the regexp @code{gnus-summary-gather-exclude-subject} to say
what subjects should be excluded from the gathering process.@*
The default is @samp{^ *$\\|^(none)$}.

@item gnus-summary-thread-gathering-function
@vindex gnus-summary-thread-gathering-function
Gnus gathers threads by looking at @code{Subject} headers.  This means
that totally unrelated articles may end up in the same ``thread'', which
is confusing.  An alternate approach is to look at all the
@code{Message-ID}s in all the @code{References} headers to find matches.
This will ensure that no gathered threads ever include unrelated
articles, but it also means that people who have posted with broken
newsreaders won't be gathered properly.  The choice is yours---plague or
cholera:

@table @code
@item gnus-gather-threads-by-subject
@findex gnus-gather-threads-by-subject
This function is the default gathering function and looks at
@code{Subject}s exclusively.

@item gnus-gather-threads-by-references
@findex gnus-gather-threads-by-references
This function looks at @code{References} headers exclusively.
@end table

If you want to test gathering by @code{References}, you could say
something like:

@lisp
(setq gnus-summary-thread-gathering-function
      'gnus-gather-threads-by-references)
@end lisp

@end table


@node Filling In Threads
@subsubsection Filling In Threads

@table @code
@item gnus-fetch-old-headers
@vindex gnus-fetch-old-headers
If non-@code{nil}, Gnus will attempt to build old threads by fetching
more old headers---headers to articles marked as read.  If you
would like to display as few summary lines as possible, but still
connect as many loose threads as possible, you should set this variable
to @code{some} or a number.  If you set it to a number, no more than
that number of extra old headers will be fetched.  In either case,
fetching old headers only works if the backend you are using carries
overview files---this would normally be @code{nntp}, @code{nnspool} and
@code{nnml}.  Also remember that if the root of the thread has been
expired by the server, there's not much Gnus can do about that.

This variable can also be set to @code{invisible}.  This won't have any
visible effects, but is useful if you use the @kbd{A T} command a lot
(@pxref{Finding the Parent}).

@item gnus-build-sparse-threads
@vindex gnus-build-sparse-threads
Fetching old headers can be slow.  A low-rent similar effect can be
gotten by setting this variable to @code{some}.  Gnus will then look at
the complete @code{References} headers of all articles and try to string
together articles that belong in the same thread.  This will leave
@dfn{gaps} in the threading display where Gnus guesses that an article
is missing from the thread.  (These gaps appear like normal summary
lines.  If you select a gap, Gnus will try to fetch the article in
question.)  If this variable is @code{t}, Gnus will display all these
``gaps'' without regard for whether they are useful for completing the
thread or not.  Finally, if this variable is @code{more}, Gnus won't cut
off sparse leaf nodes that don't lead anywhere.  This variable is
@code{nil} by default.

@end table


@node More Threading
@subsubsection More Threading

@table @code
@item gnus-show-threads
@vindex gnus-show-threads
If this variable is @code{nil}, no threading will be done, and all of
the rest of the variables here will have no effect.  Turning threading
off will speed group selection up a bit, but it is sure to make reading
slower and more awkward.

@item gnus-thread-hide-subtree
@vindex gnus-thread-hide-subtree
If non-@code{nil}, all threads will be hidden when the summary buffer is
generated.

@item gnus-thread-expunge-below
@vindex gnus-thread-expunge-below
All threads that have a total score (as defined by
@code{gnus-thread-score-function}) less than this number will be
expunged.  This variable is @code{nil} by default, which means that no
threads are expunged.

@item gnus-thread-hide-killed
@vindex gnus-thread-hide-killed
if you kill a thread and this variable is non-@code{nil}, the subtree
will be hidden.

@item gnus-thread-ignore-subject
@vindex gnus-thread-ignore-subject
Sometimes somebody changes the subject in the middle of a thread.  If
this variable is non-@code{nil}, the subject change is ignored.  If it
is @code{nil}, which is the default, a change in the subject will result
in a new thread.

@item gnus-thread-indent-level
@vindex gnus-thread-indent-level
This is a number that says how much each sub-thread should be indented.
The default is 4.

@item gnus-sort-gathered-threads-function
@vindex gnus-sort-gathered-threads-function
Sometimes, particularly with mailing lists, the order in which mails
arrive locally is not necessarily the same as the order in which they
arrived on the mailing list.  Consequently, when sorting sub-threads
using the default @code{gnus-thread-sort-by-number}, responses can end
up appearing before the article to which they are responding to.
Setting this variable to an alternate value
(e.g. @code{gnus-thread-sort-by-date}), in a group's parameters or in an
appropriate hook (e.g. @code{gnus-summary-generate-hook}) can produce a
more logical sub-thread ordering in such instances.

@end table


@node Low-Level Threading
@subsubsection Low-Level Threading

@table @code

@item gnus-parse-headers-hook
@vindex gnus-parse-headers-hook
Hook run before parsing any headers.

@item gnus-alter-header-function
@vindex gnus-alter-header-function
If non-@code{nil}, this function will be called to allow alteration of
article header structures.  The function is called with one parameter,
the article header vector, which it may alter in any way.  For instance,
if you have a mail-to-news gateway which alters the @code{Message-ID}s
in systematic ways (by adding prefixes and such), you can use this
variable to un-scramble the @code{Message-ID}s so that they are more
meaningful.  Here's one example:

@lisp
(setq gnus-alter-header-function 'my-alter-message-id)

(defun my-alter-message-id (header)
  (let ((id (mail-header-id header)))
    (when (string-match
           "\\(<[^<>@@]*\\)\\.?cygnus\\..*@@\\([^<>@@]*>\\)" id)
      (mail-header-set-id
       (concat (match-string 1 id) "@@" (match-string 2 id))
       header))))
@end lisp

@end table


@node Thread Commands
@subsection Thread Commands
@cindex thread commands

@table @kbd

@item T k
@itemx M-C-k
@kindex T k (Summary)
@kindex M-C-k (Summary)
@findex gnus-summary-kill-thread
Mark all articles in the current (sub-)thread as read
(@code{gnus-summary-kill-thread}).  If the prefix argument is positive,
remove all marks instead.  If the prefix argument is negative, tick
articles instead.

@item T l
@itemx M-C-l
@kindex T l (Summary)
@kindex M-C-l (Summary)
@findex gnus-summary-lower-thread
Lower the score of the current (sub-)thread
(@code{gnus-summary-lower-thread}).

@item T i
@kindex T i (Summary)
@findex gnus-summary-raise-thread
Increase the score of the current (sub-)thread
(@code{gnus-summary-raise-thread}).

@item T #
@kindex T # (Summary)
@findex gnus-uu-mark-thread
Set the process mark on the current (sub-)thread
(@code{gnus-uu-mark-thread}).

@item T M-#
@kindex T M-# (Summary)
@findex gnus-uu-unmark-thread
Remove the process mark from the current (sub-)thread
(@code{gnus-uu-unmark-thread}).

@item T T
@kindex T T (Summary)
@findex gnus-summary-toggle-threads
Toggle threading (@code{gnus-summary-toggle-threads}).

@item T s
@kindex T s (Summary)
@findex gnus-summary-show-thread
Expose the (sub-)thread hidden under the current article, if any
(@code{gnus-summary-show-thread}).

@item T h
@kindex T h (Summary)
@findex gnus-summary-hide-thread
Hide the current (sub-)thread (@code{gnus-summary-hide-thread}).

@item T S
@kindex T S (Summary)
@findex gnus-summary-show-all-threads
Expose all hidden threads (@code{gnus-summary-show-all-threads}).

@item T H
@kindex T H (Summary)
@findex gnus-summary-hide-all-threads
Hide all threads (@code{gnus-summary-hide-all-threads}).

@item T t
@kindex T t (Summary)
@findex gnus-summary-rethread-current
Re-thread the current article's thread
(@code{gnus-summary-rethread-current}).  This works even when the
summary buffer is otherwise unthreaded.

@item T ^
@kindex T ^ (Summary)
@findex gnus-summary-reparent-thread
Make the current article the child of the marked (or previous) article
(@code{gnus-summary-reparent-thread}).

@end table

The following commands are thread movement commands.  They all
understand the numeric prefix.

@table @kbd

@item T n
@kindex T n (Summary)
@itemx M-C-n
@kindex M-C-n (Summary)
@itemx M-down
@kindex M-down (Summary)
@findex gnus-summary-next-thread
Go to the next thread (@code{gnus-summary-next-thread}).

@item T p
@kindex T p (Summary)
@itemx M-C-p
@kindex M-C-p (Summary)
@itemx M-up
@kindex M-up (Summary)
@findex gnus-summary-prev-thread
Go to the previous thread (@code{gnus-summary-prev-thread}).

@item T d
@kindex T d (Summary)
@findex gnus-summary-down-thread
Descend the thread (@code{gnus-summary-down-thread}).

@item T u
@kindex T u (Summary)
@findex gnus-summary-up-thread
Ascend the thread (@code{gnus-summary-up-thread}).

@item T o
@kindex T o (Summary)
@findex gnus-summary-top-thread
Go to the top of the thread (@code{gnus-summary-top-thread}).
@end table

@vindex gnus-thread-operation-ignore-subject
If you ignore subject while threading, you'll naturally end up with
threads that have several different subjects in them.  If you then issue
a command like `T k' (@code{gnus-summary-kill-thread}) you might not
wish to kill the entire thread, but just those parts of the thread that
have the same subject as the current article.  If you like this idea,
you can fiddle with @code{gnus-thread-operation-ignore-subject}.  If it
is non-@code{nil} (which it is by default), subjects will be ignored
when doing thread commands.  If this variable is @code{nil}, articles in
the same thread with different subjects will not be included in the
operation in question.  If this variable is @code{fuzzy}, only articles
that have subjects fuzzily equal will be included (@pxref{Fuzzy
Matching}).


@node Sorting
@section Sorting

@findex gnus-thread-sort-by-total-score
@findex gnus-thread-sort-by-date
@findex gnus-thread-sort-by-score
@findex gnus-thread-sort-by-subject
@findex gnus-thread-sort-by-author
@findex gnus-thread-sort-by-number
@vindex gnus-thread-sort-functions
If you are using a threaded summary display, you can sort the threads by
setting @code{gnus-thread-sort-functions}, which can be either a single
function, a list of functions, or a list containing functions and
@code{(not some-function)} elements.

By default, sorting is done on article numbers.  Ready-made sorting
predicate functions include @code{gnus-thread-sort-by-number},
@code{gnus-thread-sort-by-author}, @code{gnus-thread-sort-by-subject},
@code{gnus-thread-sort-by-date}, @code{gnus-thread-sort-by-score}, and
@code{gnus-thread-sort-by-total-score}.

Each function takes two threads and returns non-@code{nil} if the first
thread should be sorted before the other.  Note that sorting really is
normally done by looking only at the roots of each thread.

If you use more than one function, the primary sort key should be the
last function in the list.  You should probably always include
@code{gnus-thread-sort-by-number} in the list of sorting
functions---preferably first.  This will ensure that threads that are
equal with respect to the other sort criteria will be displayed in
ascending article order.

If you would like to sort by reverse score, then by subject, and finally
by number, you could do something like:

@lisp
(setq gnus-thread-sort-functions
      '(gnus-thread-sort-by-number
        gnus-thread-sort-by-subject
        (not gnus-thread-sort-by-total-score)))
@end lisp

The threads that have highest score will be displayed first in the
summary buffer.  When threads have the same score, they will be sorted
alphabetically.  The threads that have the same score and the same
subject will be sorted by number, which is (normally) the sequence in
which the articles arrived.

If you want to sort by score and then reverse arrival order, you could
say something like:

@lisp
(setq gnus-thread-sort-functions
      '((lambda (t1 t2)
          (not (gnus-thread-sort-by-number t1 t2)))
        gnus-thread-sort-by-score))
@end lisp

@vindex gnus-thread-score-function
The function in the @code{gnus-thread-score-function} variable (default
@code{+}) is used for calculating the total score of a thread.  Useful
functions might be @code{max}, @code{min}, or squared means, or whatever
tickles your fancy.

@findex gnus-article-sort-functions
@findex gnus-article-sort-by-date
@findex gnus-article-sort-by-score
@findex gnus-article-sort-by-subject
@findex gnus-article-sort-by-author
@findex gnus-article-sort-by-number
If you are using an unthreaded display for some strange reason or other,
you have to fiddle with the @code{gnus-article-sort-functions} variable.
It is very similar to the @code{gnus-thread-sort-functions}, except that
it uses slightly different functions for article comparison.  Available
sorting predicate functions are @code{gnus-article-sort-by-number},
@code{gnus-article-sort-by-author}, @code{gnus-article-sort-by-subject},
@code{gnus-article-sort-by-date}, and @code{gnus-article-sort-by-score}.

If you want to sort an unthreaded summary display by subject, you could
say something like:

@lisp
(setq gnus-article-sort-functions
      '(gnus-article-sort-by-number
        gnus-article-sort-by-subject))
@end lisp



@node Asynchronous Fetching
@section Asynchronous Article Fetching
@cindex asynchronous article fetching
@cindex article pre-fetch
@cindex pre-fetch

If you read your news from an @sc{nntp} server that's far away, the
network latencies may make reading articles a chore.  You have to wait
for a while after pressing @kbd{n} to go to the next article before the
article appears.  Why can't Gnus just go ahead and fetch the article
while you are reading the previous one?  Why not, indeed.

First, some caveats.  There are some pitfalls to using asynchronous
article fetching, especially the way Gnus does it.

Let's say you are reading article 1, which is short, and article 2 is
quite long, and you are not interested in reading that.  Gnus does not
know this, so it goes ahead and fetches article 2.  You decide to read
article 3, but since Gnus is in the process of fetching article 2, the
connection is blocked.

To avoid these situations, Gnus will open two (count 'em two)
connections to the server.  Some people may think this isn't a very nice
thing to do, but I don't see any real alternatives.  Setting up that
extra connection takes some time, so Gnus startup will be slower.

Gnus will fetch more articles than you will read.  This will mean that
the link between your machine and the @sc{nntp} server will become more
loaded than if you didn't use article pre-fetch.  The server itself will
also become more loaded---both with the extra article requests, and the
extra connection.

Ok, so now you know that you shouldn't really use this thing...  unless
you really want to.

@vindex gnus-asynchronous
Here's how:  Set @code{gnus-asynchronous} to @code{t}.  The rest should
happen automatically.

@vindex gnus-use-article-prefetch
You can control how many articles are to be pre-fetched by setting
@code{gnus-use-article-prefetch}.  This is 30 by default, which means
that when you read an article in the group, the backend will pre-fetch
the next 30 articles.  If this variable is @code{t}, the backend will
pre-fetch all the articles it can without bound.  If it is
@code{nil}, no pre-fetching will be done.

@vindex gnus-async-prefetch-article-p
@findex gnus-async-read-p
There are probably some articles that you don't want to pre-fetch---read
articles, for instance.  The @code{gnus-async-prefetch-article-p} variable controls whether an article is to be pre-fetched.  This function should
return non-@code{nil} when the article in question is to be
pre-fetched.  The default is @code{gnus-async-read-p}, which returns
@code{nil} on read articles.  The function is called with an article
data structure as the only parameter.

If, for instance, you wish to pre-fetch only unread articles shorter than 100 lines, you could say something like:

@lisp
(defun my-async-short-unread-p (data)
  "Return non-nil for short, unread articles."
  (and (gnus-data-unread-p data)
       (< (mail-header-lines (gnus-data-header data))
          100)))

(setq gnus-async-prefetch-article-p 'my-async-short-unread-p)
@end lisp

These functions will be called many, many times, so they should
preferably be short and sweet to avoid slowing down Gnus too much.
It's probably a good idea to byte-compile things like this.

@vindex gnus-prefetched-article-deletion-strategy
Articles have to be removed from the asynch buffer sooner or later.  The
@code{gnus-prefetched-article-deletion-strategy} says when to remove
articles.  This is a list that may contain the following elements:

@table @code
@item read
Remove articles when they are read.

@item exit
Remove articles when exiting the group.
@end table

The default value is @code{(read exit)}.

@c @vindex gnus-use-header-prefetch
@c If @code{gnus-use-header-prefetch} is non-@code{nil}, prefetch articles
@c from the next group.


@node Article Caching
@section Article Caching
@cindex article caching
@cindex caching

If you have an @emph{extremely} slow @sc{nntp} connection, you may
consider turning article caching on.  Each article will then be stored
locally under your home directory.  As you may surmise, this could
potentially use @emph{huge} amounts of disk space, as well as eat up all
your inodes so fast it will make your head swim.  In vodka.

Used carefully, though, it could be just an easier way to save articles.

@vindex gnus-use-long-file-name
@vindex gnus-cache-directory
@vindex gnus-use-cache
To turn caching on, set @code{gnus-use-cache} to @code{t}.  By default,
all articles ticked or marked as dormant will then be copied
over to your local cache (@code{gnus-cache-directory}).  Whether this
cache is flat or hierarchal is controlled by the
@code{gnus-use-long-file-name} variable, as usual.

When re-selecting a ticked or dormant article, it will be fetched from the
cache instead of from the server.  As articles in your cache will never
expire, this might serve as a method of saving articles while still
keeping them where they belong.  Just mark all articles you want to save
as dormant, and don't worry.

When an article is marked as read, is it removed from the cache.

@vindex gnus-cache-remove-articles
@vindex gnus-cache-enter-articles
The entering/removal of articles from the cache is controlled by the
@code{gnus-cache-enter-articles} and @code{gnus-cache-remove-articles}
variables.  Both are lists of symbols.  The first is @code{(ticked
dormant)} by default, meaning that ticked and dormant articles will be
put in the cache.  The latter is @code{(read)} by default, meaning that
articles marked as read are removed from the cache.  Possibly
symbols in these two lists are @code{ticked}, @code{dormant},
@code{unread} and @code{read}.

@findex gnus-jog-cache
So where does the massive article-fetching and storing come into the
picture?  The @code{gnus-jog-cache} command will go through all
subscribed newsgroups, request all unread articles, score them, and
store them in the cache.  You should only ever, ever ever ever, use this
command if 1) your connection to the @sc{nntp} server is really, really,
really slow and 2) you have a really, really, really huge disk.
Seriously.  One way to cut down on the number of articles downloaded is
to score unwanted articles down and have them marked as read.  They will
not then be downloaded by this command.

@vindex gnus-uncacheable-groups
@vindex gnus-cacheable-groups
It is likely that you do not want caching on all groups.  For instance,
if your @code{nnml} mail is located under your home directory, it makes no
sense to cache it somewhere else under your home directory.  Unless you
feel that it's neat to use twice as much space.

To limit the caching, you could set @code{gnus-cacheable-groups} to a
regexp of groups to cache, @samp{^nntp} for instance, or set the
@code{gnus-uncacheable-groups} regexp to @samp{^nnml}, for instance.
Both variables are @code{nil} by default.  If a group matches both
variables, the group is not cached.

@findex gnus-cache-generate-nov-databases
@findex gnus-cache-generate-active
@vindex gnus-cache-active-file
The cache stores information on what articles it contains in its active
file (@code{gnus-cache-active-file}).  If this file (or any other parts
of the cache) becomes all messed up for some reason or other, Gnus
offers two functions that will try to set things right.  @kbd{M-x
gnus-cache-generate-nov-databases} will (re)build all the @sc{nov}
files, and @kbd{gnus-cache-generate-active} will (re)generate the active
file.


@node Persistent Articles
@section Persistent Articles
@cindex persistent articles

Closely related to article caching, we have @dfn{persistent articles}.
In fact, it's just a different way of looking at caching, and much more
useful in my opinion.

Say you're reading a newsgroup, and you happen on to some valuable gem
that you want to keep and treasure forever.  You'd normally just save it
(using one of the many saving commands) in some file.  The problem with
that is that it's just, well, yucky.  Ideally you'd prefer just having
the article remain in the group where you found it forever; untouched by
the expiry going on at the news server.

This is what a @dfn{persistent article} is---an article that just won't
be deleted.  It's implemented using the normal cache functions, but
you use two explicit commands for managing persistent articles:

@table @kbd

@item *
@kindex * (Summary)
@findex gnus-cache-enter-article
Make the current article persistent (@code{gnus-cache-enter-article}).

@item M-*
@kindex M-* (Summary)
@findex gnus-cache-remove-article
Remove the current article from the persistent articles
(@code{gnus-cache-remove-article}).  This will normally delete the
article.
@end table

Both these commands understand the process/prefix convention.

To avoid having all ticked articles (and stuff) entered into the cache,
you should set @code{gnus-use-cache} to @code{passive} if you're just
interested in persistent articles:

@lisp
(setq gnus-use-cache 'passive)
@end lisp


@node Article Backlog
@section Article Backlog
@cindex backlog
@cindex article backlog

If you have a slow connection, but the idea of using caching seems
unappealing to you (and it is, really), you can help the situation some
by switching on the @dfn{backlog}.  This is where Gnus will buffer
already read articles so that it doesn't have to re-fetch articles
you've already read.  This only helps if you are in the habit of
re-selecting articles you've recently read, of course.  If you never do
that, turning the backlog on will slow Gnus down a little bit, and
increase memory usage some.

@vindex gnus-keep-backlog
If you set @code{gnus-keep-backlog} to a number @var{n}, Gnus will store
at most @var{n} old articles in a buffer for later re-fetching.  If this
variable is non-@code{nil} and is not a number, Gnus will store
@emph{all} read articles, which means that your Emacs will grow without
bound before exploding and taking your machine down with you.  I put
that in there just to keep y'all on your toes.

This variable is @code{nil} by default.


@node Saving Articles
@section Saving Articles
@cindex saving articles

Gnus can save articles in a number of ways.  Below is the documentation
for saving articles in a fairly straight-forward fashion (i.e., little
processing of the article is done before it is saved).  For a different
approach (uudecoding, unsharing) you should use @code{gnus-uu}
(@pxref{Decoding Articles}).

@vindex gnus-save-all-headers
If @code{gnus-save-all-headers} is non-@code{nil}, Gnus will not delete
unwanted headers before saving the article.

@vindex gnus-saved-headers
If the preceding variable is @code{nil}, all headers that match the
@code{gnus-saved-headers} regexp will be kept, while the rest will be
deleted before saving.

@table @kbd

@item O o
@itemx o
@kindex O o (Summary)
@kindex o (Summary)
@findex gnus-summary-save-article
@c @icon{gnus-summary-save-article}
Save the current article using the default article saver
(@code{gnus-summary-save-article}).

@item O m
@kindex O m (Summary)
@findex gnus-summary-save-article-mail
Save the current article in mail format
(@code{gnus-summary-save-article-mail}).

@item O r
@kindex O r (Summary)
@findex gnus-summary-save-article-rmail
Save the current article in rmail format
(@code{gnus-summary-save-article-rmail}).

@item O f
@kindex O f (Summary)
@findex gnus-summary-save-article-file
@c @icon{gnus-summary-save-article-file}
Save the current article in plain file format
(@code{gnus-summary-save-article-file}).

@item O F
@kindex O F (Summary)
@findex gnus-summary-write-article-file
Write the current article in plain file format, overwriting any previous
file contents (@code{gnus-summary-write-article-file}).

@item O b
@kindex O b (Summary)
@findex gnus-summary-save-article-body-file
Save the current article body in plain file format
(@code{gnus-summary-save-article-body-file}).

@item O h
@kindex O h (Summary)
@findex gnus-summary-save-article-folder
Save the current article in mh folder format
(@code{gnus-summary-save-article-folder}).

@item O v
@kindex O v (Summary)
@findex gnus-summary-save-article-vm
Save the current article in a VM folder
(@code{gnus-summary-save-article-vm}).

@item O p
@kindex O p (Summary)
@findex gnus-summary-pipe-output
Save the current article in a pipe.  Uhm, like, what I mean is---Pipe
the current article to a process (@code{gnus-summary-pipe-output}).
@end table

@vindex gnus-prompt-before-saving
All these commands use the process/prefix convention
(@pxref{Process/Prefix}).  If you save bunches of articles using these
functions, you might get tired of being prompted for files to save each
and every article in.  The prompting action is controlled by
the @code{gnus-prompt-before-saving} variable, which is @code{always} by
default, giving you that excessive prompting action you know and
loathe.  If you set this variable to @code{t} instead, you'll be prompted
just once for each series of articles you save.  If you like to really
have Gnus do all your thinking for you, you can even set this variable
to @code{nil}, which means that you will never be prompted for files to
save articles in.  Gnus will simply save all the articles in the default
files.


@vindex gnus-default-article-saver
You can customize the @code{gnus-default-article-saver} variable to make
Gnus do what you want it to.  You can use any of the six ready-made
functions below, or you can create your own.

@table @code

@item gnus-summary-save-in-rmail
@findex gnus-summary-save-in-rmail
@vindex gnus-rmail-save-name
@findex gnus-plain-save-name
This is the default format, @dfn{babyl}.  Uses the function in the
@code{gnus-rmail-save-name} variable to get a file name to save the
article in.  The default is @code{gnus-plain-save-name}.

@item gnus-summary-save-in-mail
@findex gnus-summary-save-in-mail
@vindex gnus-mail-save-name
Save in a Unix mail (mbox) file.  Uses the function in the
@code{gnus-mail-save-name} variable to get a file name to save the
article in.  The default is @code{gnus-plain-save-name}.

@item gnus-summary-save-in-file
@findex gnus-summary-save-in-file
@vindex gnus-file-save-name
@findex gnus-numeric-save-name
Append the article straight to an ordinary file.  Uses the function in
the @code{gnus-file-save-name} variable to get a file name to save the
article in.  The default is @code{gnus-numeric-save-name}.

@item gnus-summary-save-body-in-file
@findex gnus-summary-save-body-in-file
Append the article body to an ordinary file.  Uses the function in the
@code{gnus-file-save-name} variable to get a file name to save the
article in.  The default is @code{gnus-numeric-save-name}.

@item gnus-summary-save-in-folder
@findex gnus-summary-save-in-folder
@findex gnus-folder-save-name
@findex gnus-Folder-save-name
@vindex gnus-folder-save-name
@cindex rcvstore
@cindex MH folders
Save the article to an MH folder using @code{rcvstore} from the MH
library.  Uses the function in the @code{gnus-folder-save-name} variable
to get a file name to save the article in.  The default is
@code{gnus-folder-save-name}, but you can also use
@code{gnus-Folder-save-name}, which creates capitalized names.

@item gnus-summary-save-in-vm
@findex gnus-summary-save-in-vm
Save the article in a VM folder.  You have to have the VM mail
reader to use this setting.
@end table

@vindex gnus-article-save-directory
All of these functions, except for the last one, will save the article
in the @code{gnus-article-save-directory}, which is initialized from the
@code{SAVEDIR} environment variable.  This is @file{~/News/} by
default.

As you can see above, the functions use different functions to find a
suitable name of a file to save the article in.  Below is a list of
available functions that generate names:

@table @code

@item gnus-Numeric-save-name
@findex gnus-Numeric-save-name
File names like @file{~/News/Alt.andrea-dworkin/45}.

@item gnus-numeric-save-name
@findex gnus-numeric-save-name
File names like @file{~/News/alt.andrea-dworkin/45}.

@item gnus-Plain-save-name
@findex gnus-Plain-save-name
File names like @file{~/News/Alt.andrea-dworkin}.

@item gnus-plain-save-name
@findex gnus-plain-save-name
File names like @file{~/News/alt.andrea-dworkin}.
@end table

@vindex gnus-split-methods
You can have Gnus suggest where to save articles by plonking a regexp into
the @code{gnus-split-methods} alist.  For instance, if you would like to
save articles related to Gnus in the file @file{gnus-stuff}, and articles
related to VM in @code{vm-stuff}, you could set this variable to something
like:

@lisp
(("^Subject:.*gnus\\|^Newsgroups:.*gnus" "gnus-stuff")
 ("^Subject:.*vm\\|^Xref:.*vm" "vm-stuff")
 (my-choosing-function "../other-dir/my-stuff")
 ((equal gnus-newsgroup-name "mail.misc") "mail-stuff"))
@end lisp

We see that this is a list where each element is a list that has two
elements---the @dfn{match} and the @dfn{file}.  The match can either be
a string (in which case it is used as a regexp to match on the article
head); it can be a symbol (which will be called as a function with the
group name as a parameter); or it can be a list (which will be
@code{eval}ed).  If any of these actions have a non-@code{nil} result,
the @dfn{file} will be used as a default prompt.  In addition, the
result of the operation itself will be used if the function or form
called returns a string or a list of strings.

You basically end up with a list of file names that might be used when
saving the current article.  (All ``matches'' will be used.)  You will
then be prompted for what you really want to use as a name, with file
name completion over the results from applying this variable.

This variable is @code{((gnus-article-archive-name))} by default, which
means that Gnus will look at the articles it saves for an
@code{Archive-name} line and use that as a suggestion for the file
name.

Here's an example function to clean up file names somewhat.  If you have
lots of mail groups called things like
@samp{nnml:mail.whatever}, you may want to chop off the beginning of
these group names before creating the file name to save to.  The
following will do just that:

@lisp
(defun my-save-name (group)
  (when (string-match "^nnml:mail." group)
    (substring group (match-end 0))))

(setq gnus-split-methods
      '((gnus-article-archive-name)
        (my-save-name)))
@end lisp


@vindex gnus-use-long-file-name
Finally, you have the @code{gnus-use-long-file-name} variable.  If it is
@code{nil}, all the preceding functions will replace all periods
(@samp{.}) in the group names with slashes (@samp{/})---which means that
the functions will generate hierarchies of directories instead of having
all the files in the top level directory
(@file{~/News/alt/andrea-dworkin} instead of
@file{~/News/alt.andrea-dworkin}.)  This variable is @code{t} by default
on most systems.  However, for historical reasons, this is @code{nil} on
Xenix and usg-unix-v machines by default.

This function also affects kill and score file names.  If this variable
is a list, and the list contains the element @code{not-score}, long file
names will not be used for score files, if it contains the element
@code{not-save}, long file names will not be used for saving, and if it
contains the element @code{not-kill}, long file names will not be used
for kill files.

If you'd like to save articles in a hierarchy that looks something like
a spool, you could

@lisp
(setq gnus-use-long-file-name '(not-save)) ; to get a hierarchy
(setq gnus-default-article-saver 'gnus-summary-save-in-file) ; no encoding
@end lisp

Then just save with @kbd{o}.  You'd then read this hierarchy with
ephemeral @code{nneething} groups---@kbd{G D} in the group buffer, and
the top level directory as the argument (@file{~/News/}).  Then just walk
around to the groups/directories with @code{nneething}.


@node Decoding Articles
@section Decoding Articles
@cindex decoding articles

Sometime users post articles (or series of articles) that have been
encoded in some way or other.  Gnus can decode them for you.

@menu
* Uuencoded Articles::    Uudecode articles.
* Shell Archives::        Unshar articles.
* PostScript Files::      Split PostScript.
* Other Files::           Plain save and binhex.
* Decoding Variables::    Variables for a happy decoding.
* Viewing Files::         You want to look at the result of the decoding?
@end menu

@cindex series
@cindex article series
All these functions use the process/prefix convention
(@pxref{Process/Prefix}) for finding out what articles to work on, with
the extension that a ``single article'' means ``a single series''.  Gnus
can find out by itself what articles belong to a series, decode all the
articles and unpack/view/save the resulting file(s).

Gnus guesses what articles are in the series according to the following
simplish rule: The subjects must be (nearly) identical, except for the
last two numbers of the line.  (Spaces are largely ignored, however.)

For example: If you choose a subject called @samp{cat.gif (2/3)}, Gnus
will find all the articles that match the regexp @samp{^cat.gif
([0-9]+/[0-9]+).*$}.

Subjects that are non-standard, like @samp{cat.gif (2/3) Part 6 of a
series}, will not be properly recognized by any of the automatic viewing
commands, and you have to mark the articles manually with @kbd{#}.


@node Uuencoded Articles
@subsection Uuencoded Articles
@cindex uudecode
@cindex uuencoded articles

@table @kbd

@item X u
@kindex X u (Summary)
@findex gnus-uu-decode-uu
@c @icon{gnus-uu-decode-uu}
Uudecodes the current series (@code{gnus-uu-decode-uu}).

@item X U
@kindex X U (Summary)
@findex gnus-uu-decode-uu-and-save
Uudecodes and saves the current series
(@code{gnus-uu-decode-uu-and-save}).

@item X v u
@kindex X v u (Summary)
@findex gnus-uu-decode-uu-view
Uudecodes and views the current series (@code{gnus-uu-decode-uu-view}).

@item X v U
@kindex X v U (Summary)
@findex gnus-uu-decode-uu-and-save-view
Uudecodes, views and saves the current series
(@code{gnus-uu-decode-uu-and-save-view}).

@end table

Remember that these all react to the presence of articles marked with
the process mark.  If, for instance, you'd like to decode and save an
entire newsgroup, you'd typically do @kbd{M P a}
(@code{gnus-uu-mark-all}) and then @kbd{X U}
(@code{gnus-uu-decode-uu-and-save}).

All this is very much different from how @code{gnus-uu} worked with
@sc{gnus 4.1}, where you had explicit keystrokes for everything under
the sun.  This version of @code{gnus-uu} generally assumes that you mark
articles in some way (@pxref{Setting Process Marks}) and then press
@kbd{X u}.

@vindex gnus-uu-notify-files
Note: When trying to decode articles that have names matching
@code{gnus-uu-notify-files}, which is hard-coded to
@samp{[Cc][Ii][Nn][Dd][Yy][0-9]+.\\(gif\\|jpg\\)}, @code{gnus-uu} will
automatically post an article on @samp{comp.unix.wizards} saying that
you have just viewed the file in question.  This feature can't be turned
off.


@node Shell Archives
@subsection Shell Archives
@cindex unshar
@cindex shell archives
@cindex shared articles

Shell archives (``shar files'') used to be a popular way to distribute
sources, but it isn't used all that much today.  In any case, we have
some commands to deal with these:

@table @kbd

@item X s
@kindex X s (Summary)
@findex gnus-uu-decode-unshar
Unshars the current series (@code{gnus-uu-decode-unshar}).

@item X S
@kindex X S (Summary)
@findex gnus-uu-decode-unshar-and-save
Unshars and saves the current series (@code{gnus-uu-decode-unshar-and-save}).

@item X v s
@kindex X v s (Summary)
@findex gnus-uu-decode-unshar-view
Unshars and views the current series (@code{gnus-uu-decode-unshar-view}).

@item X v S
@kindex X v S (Summary)
@findex gnus-uu-decode-unshar-and-save-view
Unshars, views and saves the current series
(@code{gnus-uu-decode-unshar-and-save-view}).
@end table


@node PostScript Files
@subsection PostScript Files
@cindex PostScript

@table @kbd

@item X p
@kindex X p (Summary)
@findex gnus-uu-decode-postscript
Unpack the current PostScript series (@code{gnus-uu-decode-postscript}).

@item X P
@kindex X P (Summary)
@findex gnus-uu-decode-postscript-and-save
Unpack and save the current PostScript series
(@code{gnus-uu-decode-postscript-and-save}).

@item X v p
@kindex X v p (Summary)
@findex gnus-uu-decode-postscript-view
View the current PostScript series
(@code{gnus-uu-decode-postscript-view}).

@item X v P
@kindex X v P (Summary)
@findex gnus-uu-decode-postscript-and-save-view
View and save the current PostScript series
(@code{gnus-uu-decode-postscript-and-save-view}).
@end table


@node Other Files
@subsection Other Files

@table @kbd
@item X o
@kindex X o (Summary)
@findex gnus-uu-decode-save
Save the current series
(@code{gnus-uu-decode-save}).

@item X b
@kindex X b (Summary)
@findex gnus-uu-decode-binhex
Unbinhex the current series (@code{gnus-uu-decode-binhex}).  This
doesn't really work yet.
@end table


@node Decoding Variables
@subsection Decoding Variables

Adjective, not verb.

@menu
* Rule Variables::          Variables that say how a file is to be viewed.
* Other Decode Variables::  Other decode variables.
* Uuencoding and Posting::  Variables for customizing uuencoding.
@end menu


@node Rule Variables
@subsubsection Rule Variables
@cindex rule variables

Gnus uses @dfn{rule variables} to decide how to view a file.  All these
variables are of the form

@lisp
      (list '(regexp1 command2)
            '(regexp2 command2)
            ...)
@end lisp

@table @code

@item gnus-uu-user-view-rules
@vindex gnus-uu-user-view-rules
@cindex sox
This variable is consulted first when viewing files.  If you wish to use,
for instance, @code{sox} to convert an @samp{.au} sound file, you could
say something like:
@lisp
(setq gnus-uu-user-view-rules
      (list '("\\\\.au$" "sox %s -t .aiff > /dev/audio")))
@end lisp

@item gnus-uu-user-view-rules-end
@vindex gnus-uu-user-view-rules-end
This variable is consulted if Gnus couldn't make any matches from the
user and default view rules.

@item gnus-uu-user-archive-rules
@vindex gnus-uu-user-archive-rules
This variable can be used to say what commands should be used to unpack
archives.
@end table


@node Other Decode Variables
@subsubsection Other Decode Variables

@table @code
@vindex gnus-uu-grabbed-file-functions

@item gnus-uu-grabbed-file-functions
All functions in this list will be called right after each file has been
successfully decoded---so that you can move or view files right away,
and don't have to wait for all files to be decoded before you can do
anything.  Ready-made functions you can put in this list are:

@table @code

@item gnus-uu-grab-view
@findex gnus-uu-grab-view
View the file.

@item gnus-uu-grab-move
@findex gnus-uu-grab-move
Move the file (if you're using a saving function.)
@end table

@item gnus-uu-be-dangerous
@vindex gnus-uu-be-dangerous
Specifies what to do if unusual situations arise during decoding.  If
@code{nil}, be as conservative as possible.  If @code{t}, ignore things
that didn't work, and overwrite existing files.  Otherwise, ask each
time.

@item gnus-uu-ignore-files-by-name
@vindex gnus-uu-ignore-files-by-name
Files with name matching this regular expression won't be viewed.

@item gnus-uu-ignore-files-by-type
@vindex gnus-uu-ignore-files-by-type
Files with a @sc{mime} type matching this variable won't be viewed.
Note that Gnus tries to guess what type the file is based on the name.
@code{gnus-uu} is not a @sc{mime} package (yet), so this is slightly
kludgey.

@item gnus-uu-tmp-dir
@vindex gnus-uu-tmp-dir
Where @code{gnus-uu} does its work.

@item gnus-uu-do-not-unpack-archives
@vindex gnus-uu-do-not-unpack-archives
Non-@code{nil} means that @code{gnus-uu} won't peek inside archives
looking for files to display.

@item gnus-uu-view-and-save
@vindex gnus-uu-view-and-save
Non-@code{nil} means that the user will always be asked to save a file
after viewing it.

@item gnus-uu-ignore-default-view-rules
@vindex gnus-uu-ignore-default-view-rules
Non-@code{nil} means that @code{gnus-uu} will ignore the default viewing
rules.

@item gnus-uu-ignore-default-archive-rules
@vindex gnus-uu-ignore-default-archive-rules
Non-@code{nil} means that @code{gnus-uu} will ignore the default archive
unpacking commands.

@item gnus-uu-kill-carriage-return
@vindex gnus-uu-kill-carriage-return
Non-@code{nil} means that @code{gnus-uu} will strip all carriage returns
from articles.

@item gnus-uu-unmark-articles-not-decoded
@vindex gnus-uu-unmark-articles-not-decoded
Non-@code{nil} means that @code{gnus-uu} will mark unsuccessfully
decoded articles as unread.

@item gnus-uu-correct-stripped-uucode
@vindex gnus-uu-correct-stripped-uucode
Non-@code{nil} means that @code{gnus-uu} will @emph{try} to fix
uuencoded files that have had trailing spaces deleted.

@item gnus-uu-pre-uudecode-hook
@vindex gnus-uu-pre-uudecode-hook
Hook run before sending a message to @code{uudecode}.

@item gnus-uu-view-with-metamail
@vindex gnus-uu-view-with-metamail
@cindex metamail
Non-@code{nil} means that @code{gnus-uu} will ignore the viewing
commands defined by the rule variables and just fudge a @sc{mime}
content type based on the file name.  The result will be fed to
@code{metamail} for viewing.

@item gnus-uu-save-in-digest
@vindex gnus-uu-save-in-digest
Non-@code{nil} means that @code{gnus-uu}, when asked to save without
decoding, will save in digests.  If this variable is @code{nil},
@code{gnus-uu} will just save everything in a file without any
embellishments.  The digesting almost conforms to RFC 1153---no easy way
to specify any meaningful volume and issue numbers were found, so I
simply dropped them.

@end table


@node Uuencoding and Posting
@subsubsection Uuencoding and Posting

@table @code

@item gnus-uu-post-include-before-composing
@vindex gnus-uu-post-include-before-composing
Non-@code{nil} means that @code{gnus-uu} will ask for a file to encode
before you compose the article.  If this variable is @code{t}, you can
either include an encoded file with @kbd{C-c C-i} or have one included
for you when you post the article.

@item gnus-uu-post-length
@vindex gnus-uu-post-length
Maximum length of an article.  The encoded file will be split into how
many articles it takes to post the entire file.

@item gnus-uu-post-threaded
@vindex gnus-uu-post-threaded
Non-@code{nil} means that @code{gnus-uu} will post the encoded file in a
thread.  This may not be smart, as no other decoder I have seen is able
to follow threads when collecting uuencoded articles.  (Well, I have
seen one package that does that---@code{gnus-uu}, but somehow, I don't
think that counts...) Default is @code{nil}.

@item gnus-uu-post-separate-description
@vindex gnus-uu-post-separate-description
Non-@code{nil} means that the description will be posted in a separate
article.  The first article will typically be numbered (0/x).  If this
variable is @code{nil}, the description the user enters will be included
at the beginning of the first article, which will be numbered (1/x).
Default is @code{t}.

@end table


@node Viewing Files
@subsection Viewing Files
@cindex viewing files
@cindex pseudo-articles

After decoding, if the file is some sort of archive, Gnus will attempt
to unpack the archive and see if any of the files in the archive can be
viewed.  For instance, if you have a gzipped tar file @file{pics.tar.gz}
containing the files @file{pic1.jpg} and @file{pic2.gif}, Gnus will
uncompress and de-tar the main file, and then view the two pictures.
This unpacking process is recursive, so if the archive contains archives
of archives, it'll all be unpacked.

Finally, Gnus will normally insert a @dfn{pseudo-article} for each
extracted file into the summary buffer.  If you go to these
``articles'', you will be prompted for a command to run (usually Gnus
will make a suggestion), and then the command will be run.

@vindex gnus-view-pseudo-asynchronously
If @code{gnus-view-pseudo-asynchronously} is @code{nil}, Emacs will wait
until the viewing is done before proceeding.

@vindex gnus-view-pseudos
If @code{gnus-view-pseudos} is @code{automatic}, Gnus will not insert
the pseudo-articles into the summary buffer, but view them
immediately.  If this variable is @code{not-confirm}, the user won't even
be asked for a confirmation before viewing is done.

@vindex gnus-view-pseudos-separately
If @code{gnus-view-pseudos-separately} is non-@code{nil}, one
pseudo-article will be created for each file to be viewed.  If
@code{nil}, all files that use the same viewing command will be given as
a list of parameters to that command.

@vindex gnus-insert-pseudo-articles
If @code{gnus-insert-pseudo-articles} is non-@code{nil}, insert
pseudo-articles when decoding.  It is @code{t} by default.

So; there you are, reading your @emph{pseudo-articles} in your
@emph{virtual newsgroup} from the @emph{virtual server}; and you think:
Why isn't anything real anymore? How did we get here?


@node Article Treatment
@section Article Treatment

Reading through this huge manual, you may have quite forgotten that the
object of newsreaders is to actually, like, read what people have
written.  Reading articles.  Unfortunately, people are quite bad at
writing, so there are tons of functions and variables to make reading
these articles easier.

@menu
* Article Highlighting::    You want to make the article look like fruit salad.
* Article Fontisizing::     Making emphasized text look nice.
* Article Hiding::          You also want to make certain info go away.
* Article Washing::         Lots of way-neat functions to make life better.
* Article Buttons::         Click on URLs, Message-IDs, addresses and the like.
* Article Date::            Grumble, UT!
* Article Signature::       What is a signature?
* Article Miscellania::     Various other stuff.
@end menu


@node Article Highlighting
@subsection Article Highlighting
@cindex highlighting

Not only do you want your article buffer to look like fruit salad, but
you want it to look like technicolor fruit salad.

@table @kbd

@item W H a
@kindex W H a (Summary)
@findex gnus-article-highlight
@findex gnus-article-maybe-highlight
Do much highlighting of the current article
(@code{gnus-article-highlight}).  This function highlights header, cited
text, the signature, and adds buttons to the body and the head.

@item W H h
@kindex W H h (Summary)
@findex gnus-article-highlight-headers
@vindex gnus-header-face-alist
Highlight the headers (@code{gnus-article-highlight-headers}).  The
highlighting will be done according to the @code{gnus-header-face-alist}
variable, which is a list where each element has the form
@code{(@var{regexp} @var{name} @var{content})}.
@var{regexp} is a regular expression for matching the
header, @var{name} is the face used for highlighting the header name
(@pxref{Faces and Fonts}) and @var{content} is the face for highlighting
the header value.  The first match made will be used.  Note that
@var{regexp} shouldn't have @samp{^} prepended---Gnus will add one.

@item W H c
@kindex W H c (Summary)
@findex gnus-article-highlight-citation
Highlight cited text (@code{gnus-article-highlight-citation}).

Some variables to customize the citation highlights:

@table @code
@vindex gnus-cite-parse-max-size

@item gnus-cite-parse-max-size
If the article size if bigger than this variable (which is 25000 by
default), no citation highlighting will be performed.

@item gnus-cite-max-prefix
@vindex gnus-cite-max-prefix
Maximum possible length for a citation prefix (default 20).

@item gnus-cite-face-list
@vindex gnus-cite-face-list
List of faces used for highlighting citations (@pxref{Faces and Fonts}).
When there are citations from multiple articles in the same message,
Gnus will try to give each citation from each article its own face.
This should make it easier to see who wrote what.

@item gnus-supercite-regexp
@vindex gnus-supercite-regexp
Regexp matching normal Supercite attribution lines.

@item gnus-supercite-secondary-regexp
@vindex gnus-supercite-secondary-regexp
Regexp matching mangled Supercite attribution lines.

@item gnus-cite-minimum-match-count
@vindex gnus-cite-minimum-match-count
Minimum number of identical prefixes we have to see before we believe
that it's a citation.

@item gnus-cite-attribution-prefix
@vindex gnus-cite-attribution-prefix
Regexp matching the beginning of an attribution line.

@item gnus-cite-attribution-suffix
@vindex gnus-cite-attribution-suffix
Regexp matching the end of an attribution line.

@item gnus-cite-attribution-face
@vindex gnus-cite-attribution-face
Face used for attribution lines.  It is merged with the face for the
cited text belonging to the attribution.

@end table


@item W H s
@kindex W H s (Summary)
@vindex gnus-signature-separator
@vindex gnus-signature-face
@findex gnus-article-highlight-signature
Highlight the signature (@code{gnus-article-highlight-signature}).
Everything after @code{gnus-signature-separator} (@pxref{Article
Signature}) in an article will be considered a signature and will be
highlighted with @code{gnus-signature-face}, which is @code{italic} by
default.

@end table

@xref{Customizing Articles}, for how to highlight articles automatically.


@node Article Fontisizing
@subsection Article Fontisizing
@cindex emphasis
@cindex article emphasis

@findex gnus-article-emphasize
@kindex W e (Summary)
People commonly add emphasis to words in news articles by writing things
like @samp{_this_} or @samp{*this*} or @samp{/this/}.  Gnus can make
this look nicer by running the article through the @kbd{W e}
(@code{gnus-article-emphasize}) command.

@vindex gnus-emphasis-alist
How the emphasis is computed is controlled by the
@code{gnus-emphasis-alist} variable.  This is an alist where the first
element is a regular expression to be matched.  The second is a number
that says what regular expression grouping is used to find the entire
emphasized word.  The third is a number that says what regexp grouping
should be displayed and highlighted.  (The text between these two
groupings will be hidden.)  The fourth is the face used for
highlighting.

@lisp
(setq gnus-article-emphasis
      '(("_\\(\\w+\\)_" 0 1 gnus-emphasis-underline)
        ("\\*\\(\\w+\\)\\*" 0 1 gnus-emphasis-bold)))
@end lisp

@cindex slash
@cindex asterisk
@cindex underline
@cindex /
@cindex *

@vindex gnus-emphasis-underline
@vindex gnus-emphasis-bold
@vindex gnus-emphasis-italic
@vindex gnus-emphasis-underline-bold
@vindex gnus-emphasis-underline-italic
@vindex gnus-emphasis-bold-italic
@vindex gnus-emphasis-underline-bold-italic
By default, there are seven rules, and they use the following faces:
@code{gnus-emphasis-bold}, @code{gnus-emphasis-italic},
@code{gnus-emphasis-underline}, @code{gnus-emphasis-bold-italic},
@code{gnus-emphasis-underline-italic},
@code{gnus-emphasis-underline-bold}, and
@code{gnus-emphasis-underline-bold-italic}.

If you want to change these faces, you can either use @kbd{M-x
customize}, or you can use @code{copy-face}.  For instance, if you want
to make @code{gnus-emphasis-italic} use a red face instead, you could
say something like:

@lisp
(copy-face 'red 'gnus-emphasis-italic)
@end lisp

@vindex gnus-group-highlight-words-alist

If you want to highlight arbitrary words, you can use the
@code{gnus-group-highlight-words-alist} variable, which uses the same
syntax as @code{gnus-emphasis-alist}.  The @code{highlight-words} group
parameter (@pxref{Group Parameters}) can also be used.

@xref{Customizing Articles}, for how to fontize articles automatically.


@node Article Hiding
@subsection Article Hiding
@cindex article hiding

Or rather, hiding certain things in each article.  There usually is much
too much cruft in most articles.

@table @kbd

@item W W a
@kindex W W a (Summary)
@findex gnus-article-hide
Do quite a lot of hiding on the article buffer
(@kbd{gnus-article-hide}).  In particular, this function will hide
headers, PGP, cited text and the signature.

@item W W h
@kindex W W h (Summary)
@findex gnus-article-hide-headers
Hide headers (@code{gnus-article-hide-headers}).  @xref{Hiding
Headers}.

@item W W b
@kindex W W b (Summary)
@findex gnus-article-hide-boring-headers
Hide headers that aren't particularly interesting
(@code{gnus-article-hide-boring-headers}).  @xref{Hiding Headers}.

@item W W s
@kindex W W s (Summary)
@findex gnus-article-hide-signature
Hide signature (@code{gnus-article-hide-signature}).  @xref{Article
Signature}.

@item W W l
@kindex W W l (Summary)
@findex gnus-article-hide-list-identifiers
@vindex gnus-list-identifiers
Strip list identifiers specified in @code{gnus-list-identifiers}.  These
are strings some mailing list servers add to the beginning of all
@code{Subject} headers---for example, @samp{[zebra 4711]}.  Any leading
@samp{Re: } is skipped before stripping. @code{gnus-list-identifiers}
may not contain @code{\\(..\\)}.

@table @code

@item gnus-list-identifiers
@vindex gnus-list-identifiers
A regular expression that matches list identifiers to be removed from
subject.  This can also be a list of regular expressions.

@end table

@item W W p
@kindex W W p (Summary)
@findex gnus-article-hide-pgp
@vindex gnus-article-hide-pgp-hook
Hide @sc{pgp} signatures (@code{gnus-article-hide-pgp}).  The
@code{gnus-article-hide-pgp-hook} hook will be run after a @sc{pgp}
signature has been hidden.  For example, to automatically verify
articles that have signatures in them do:
@lisp
;;; Hide pgp cruft if any.

(setq gnus-treat-strip-pgp t)

;;; After hiding pgp, verify the message;
;;; only happens if pgp signature is found.

(add-hook 'gnus-article-hide-pgp-hook
          (lambda ()
            (save-excursion
              (set-buffer gnus-original-article-buffer)
              (mc-verify))))
@end lisp

@item W W P
@kindex W W P (Summary)
@findex gnus-article-hide-pem
Hide @sc{pem} (privacy enhanced messages) cruft
(@code{gnus-article-hide-pem}).

@item W W B
@kindex W W B (Summary)
@findex gnus-article-strip-banner
@cindex banner
@cindex OneList
@cindex stripping advertisments
@cindex advertisments
Strip the banner specified by the @code{banner} group parameter
(@code{gnus-article-strip-banner}).  This is mainly used to hide those
annoying banners and/or signatures that some mailing lists and moderated
groups adds to all the messages.  The way to use this function is to add
the @code{banner} group parameter (@pxref{Group Parameters}) to the
group you want banners stripped from.  The parameter either be a string,
which will be interpreted as a regular expression matching text to be
removed, or the symbol @code{signature}, meaning that the (last)
signature should be removed, or other symbol, meaning that the
corresponding regular expression in @code{gnus-article-banner-alist} is
used.

@item W W c
@kindex W W c (Summary)
@findex gnus-article-hide-citation
Hide citation (@code{gnus-article-hide-citation}).  Some variables for
customizing the hiding:

@table @code

@item gnus-cited-opened-text-button-line-format
@itemx gnus-cited-closed-text-button-line-format
@vindex gnus-cited-closed-text-button-line-format
@vindex gnus-cited-opened-text-button-line-format
Gnus adds buttons to show where the cited text has been hidden, and to
allow toggle hiding the text.  The format of the variable is specified
by these format-like variable (@pxref{Formatting Variables}).  These
specs are valid:

@table @samp
@item b
Starting point of the hidden text.
@item e
Ending point of the hidden text.
@item l
Number of characters in the hidden region.
@item n
Number of lines of hidden text.
@end table

@item gnus-cited-lines-visible
@vindex gnus-cited-lines-visible
The number of lines at the beginning of the cited text to leave
shown. This can also be a cons cell with the number of lines at the top
and bottom of the text, respectively, to remain visible.

@end table

@item W W C-c
@kindex W W C-c (Summary)
@findex gnus-article-hide-citation-maybe

Hide citation (@code{gnus-article-hide-citation-maybe}) depending on the
following two variables:

@table @code
@item gnus-cite-hide-percentage
@vindex gnus-cite-hide-percentage
If the cited text is of a bigger percentage than this variable (default
50), hide the cited text.

@item gnus-cite-hide-absolute
@vindex gnus-cite-hide-absolute
The cited text must have at least this length (default 10) before it
is hidden.
@end table

@item W W C
@kindex W W C (Summary)
@findex gnus-article-hide-citation-in-followups
Hide cited text in articles that aren't roots
(@code{gnus-article-hide-citation-in-followups}).  This isn't very
useful as an interactive command, but might be a handy function to stick
have happen automatically (@pxref{Customizing Articles}).

@end table

All these ``hiding'' commands are toggles, but if you give a negative
prefix to these commands, they will show what they have previously
hidden.  If you give a positive prefix, they will always hide.

Also @pxref{Article Highlighting} for further variables for
citation customization.

@xref{Customizing Articles}, for how to hide article elements
automatically.


@node Article Washing
@subsection Article Washing
@cindex washing
@cindex article washing

We call this ``article washing'' for a really good reason.  Namely, the
@kbd{A} key was taken, so we had to use the @kbd{W} key instead.

@dfn{Washing} is defined by us as ``changing something from something to
something else'', but normally results in something looking better.
Cleaner, perhaps.

@table @kbd

@item W l
@kindex W l (Summary)
@findex gnus-summary-stop-page-breaking
Remove page breaks from the current article
(@code{gnus-summary-stop-page-breaking}).  @xref{Misc Article}, for page
delimiters.

@item W r
@kindex W r (Summary)
@findex gnus-summary-caesar-message
@c @icon{gnus-summary-caesar-message}
Do a Caesar rotate (rot13) on the article buffer
(@code{gnus-summary-caesar-message}).
Unreadable articles that tell you to read them with Caesar rotate or rot13.
(Typically offensive jokes and such.)

It's commonly called ``rot13'' because each letter is rotated 13
positions in the alphabet, e. g. @samp{B} (letter #2) -> @samp{O} (letter
#15).  It is sometimes referred to as ``Caesar rotate'' because Caesar
is rumored to have employed this form of, uh, somewhat weak encryption.

@item W t
@item t
@kindex W t (Summary)
@kindex t (Summary)
@findex gnus-summary-toggle-header
Toggle whether to display all headers in the article buffer
(@code{gnus-summary-toggle-header}).

@item W v
@kindex W v (Summary)
@findex gnus-summary-verbose-header
Toggle whether to display all headers in the article buffer permanently
(@code{gnus-summary-verbose-header}).

@item W o
@kindex W o (Summary)
@findex gnus-article-treat-overstrike
Treat overstrike (@code{gnus-article-treat-overstrike}).

@item W d
@kindex W d (Summary)
@findex gnus-article-treat-dumbquotes
@vindex gnus-article-dumbquotes-map
@cindex Smartquotes
@cindex M****s*** sm*rtq**t*s
@cindex Latin 1
Treat M****s*** sm*rtq**t*s according to
@code{gnus-article-dumbquotes-map}
(@code{gnus-article-treat-dumbquotes}).  Note that this function guesses
whether a character is a sm*rtq**t* or not, so it should only be used
interactively.

Sm*rtq**t*s are M****s***'s unilateral extension to the character map in
an attempt to provide more quoting characters.  If you see something
like @code{\222} or @code{\264} where you're expecting some kind of
apostrophe or quotation mark, then try this wash.

@item W w
@kindex W w (Summary)
@findex gnus-article-fill-cited-article
Do word wrap (@code{gnus-article-fill-cited-article}).

You can give the command a numerical prefix to specify the width to use
when filling.

@item W Q
@kindex W Q (Summary)
@findex gnus-article-fill-long-lines 
Fill long lines (@code{gnus-article-fill-long-lines}).

@item W C
@kindex W C (Summary)
@findex gnus-article-capitalize-sentences
Capitalize the first word in each sentence
(@code{gnus-article-capitalize-sentences}).

@item W c
@kindex W c (Summary)
@findex gnus-article-remove-cr
Translate CRLF pairs (i. e., @samp{^M}s on the end of the lines) into LF
(this takes care of DOS line endings), and then translate any remaining
CRs into LF (this takes care of Mac line endings)
(@code{gnus-article-remove-cr}).

@item W q
@kindex W q (Summary)
@findex gnus-article-de-quoted-unreadable
Treat quoted-printable (@code{gnus-article-de-quoted-unreadable}).
Quoted-Printable is one common @sc{mime} encoding employed when sending
non-ASCII (i. e., 8-bit) articles.  It typically makes strings like
@samp{déjà vu} look like @samp{d=E9j=E0 vu}, which doesn't look very
readable to me.  Note that the this is usually done automatically by
Gnus if the message in question has a @code{Content-Transfer-Encoding}
header that says that this encoding has been done.

@item W 6
@kindex W 6 (Summary)
@findex gnus-article-de-base64-unreadable
Treat base64 (@code{gnus-article-de-base64-unreadable}).
Base64 is one common @sc{mime} encoding employed when sending non-ASCII
(i. e., 8-bit) articles.  Note that the this is usually done
automatically by Gnus if the message in question has a
@code{Content-Transfer-Encoding} header that says that this encoding has
been done.

@item W Z
@kindex W Z (Summary)
@findex gnus-article-decode-HZ
Treat HZ or HZP (@code{gnus-article-decode-HZ}).  HZ (or HZP) is one
common encoding employed when sending Chinese articles.  It typically
makes strings look like @samp{~@{<:Ky2;S@{#,NpJ)l6HK!#~@}}.

@item W h
@kindex W h (Summary)
@findex gnus-article-wash-html
Treat HTML (@code{gnus-article-wash-html}).  
Note that the this is usually done automatically by Gnus if the message
in question has a @code{Content-Type} header that says that this type
has been done.

@item W f
@kindex W f (Summary)
@cindex x-face
@findex gnus-article-display-x-face
@findex gnus-article-x-face-command
@vindex gnus-article-x-face-command
@vindex gnus-article-x-face-too-ugly
@iftex
@iflatex
\include{xface}
@end iflatex
@end iftex
Look for and display any X-Face headers
(@code{gnus-article-display-x-face}).  The command executed by this
function is given by the @code{gnus-article-x-face-command} variable.
If this variable is a string, this string will be executed in a
sub-shell.  If it is a function, this function will be called with the
face as the argument.  If the @code{gnus-article-x-face-too-ugly} (which
is a regexp) matches the @code{From} header, the face will not be shown.
The default action under Emacs is to fork off the @code{display}
program@footnote{@code{display} is from the ImageMagick package.  For the
@code{uncompface} and @code{icontopbm} programs look for a package
like `compface' or `faces-xface' on a GNU/Linux system.}
to view the face.  Under XEmacs or Emacs 21+ with suitable image
support, the default action is to display the face before the
@code{From} header.  (It's nicer if XEmacs has been compiled with X-Face
support---that will make display somewhat faster.  If there's no native
X-Face support, Gnus will try to convert the @code{X-Face} header using
external programs from the @code{pbmplus} package and
friends.@footnote{On a GNU/Linux system look for packages with names
like @code{netpbm} or @code{libgr-progs}.})  If you
want to have this function in the display hook, it should probably come
last.

@item W b
@kindex W b (Summary)
@findex gnus-article-add-buttons
Add clickable buttons to the article (@code{gnus-article-add-buttons}).
@xref{Article Buttons}.

@item W B
@kindex W B (Summary)
@findex gnus-article-add-buttons-to-head
Add clickable buttons to the article headers
(@code{gnus-article-add-buttons-to-head}).

@item W W H
@kindex W W H (Summary)
@findex gnus-article-strip-headers-from-body
Strip headers like the @code{X-No-Archive} header from the beginning of
article bodies (@code{gnus-article-strip-headers-from-body}).

@item W E l
@kindex W E l (Summary)
@findex gnus-article-strip-leading-blank-lines
Remove all blank lines from the beginning of the article
(@code{gnus-article-strip-leading-blank-lines}).

@item W E m
@kindex W E m (Summary)
@findex gnus-article-strip-multiple-blank-lines
Replace all blank lines with empty lines and then all multiple empty
lines with a single empty line.
(@code{gnus-article-strip-multiple-blank-lines}).

@item W E t
@kindex W E t (Summary)
@findex gnus-article-remove-trailing-blank-lines
Remove all blank lines at the end of the article
(@code{gnus-article-remove-trailing-blank-lines}).

@item W E a
@kindex W E a (Summary)
@findex gnus-article-strip-blank-lines
Do all the three commands above
(@code{gnus-article-strip-blank-lines}).

@item W E A
@kindex W E A (Summary)
@findex gnus-article-strip-all-blank-lines
Remove all blank lines
(@code{gnus-article-strip-all-blank-lines}).

@item W E s
@kindex W E s (Summary)
@findex gnus-article-strip-leading-space
Remove all white space from the beginning of all lines of the article
body (@code{gnus-article-strip-leading-space}).

@item W E e
@kindex W E e (Summary)
@findex gnus-article-strip-trailing-space
Remove all white space from the end of all lines of the article
body (@code{gnus-article-strip-trailing-space}).

@end table

@xref{Customizing Articles}, for how to wash articles automatically.


@node Article Buttons
@subsection Article Buttons
@cindex buttons

People often include references to other stuff in articles, and it would
be nice if Gnus could just fetch whatever it is that people talk about
with the minimum of fuzz when you hit @kbd{RET} or use the middle mouse
button on these references.

Gnus adds @dfn{buttons} to certain standard references by default:
Well-formed URLs, mail addresses and Message-IDs.  This is controlled by
two variables, one that handles article bodies and one that handles
article heads:

@table @code

@item gnus-button-alist
@vindex gnus-button-alist
This is an alist where each entry has this form:

@lisp
(REGEXP BUTTON-PAR USE-P FUNCTION DATA-PAR)
@end lisp

@table @var

@item regexp
All text that match this regular expression will be considered an
external reference.  Here's a typical regexp that matches embedded URLs:
@samp{<URL:\\([^\n\r>]*\\)>}.

@item button-par
Gnus has to know which parts of the matches is to be highlighted.  This
is a number that says what sub-expression of the regexp is to be
highlighted.  If you want it all highlighted, you use 0 here.

@item use-p
This form will be @code{eval}ed, and if the result is non-@code{nil},
this is considered a match.  This is useful if you want extra sifting to
avoid false matches.

@item function
This function will be called when you click on this button.

@item data-par
As with @var{button-par}, this is a sub-expression number, but this one
says which part of the match is to be sent as data to @var{function}.

@end table

So the full entry for buttonizing URLs is then

@lisp
("<URL:\\([^\n\r>]*\\)>" 0 t gnus-button-url 1)
@end lisp

@item gnus-header-button-alist
@vindex gnus-header-button-alist
This is just like the other alist, except that it is applied to the
article head only, and that each entry has an additional element that is
used to say what headers to apply the buttonize coding to:

@lisp
(HEADER REGEXP BUTTON-PAR USE-P FUNCTION DATA-PAR)
@end lisp

@var{header} is a regular expression.

@item gnus-button-url-regexp
@vindex gnus-button-url-regexp
A regular expression that matches embedded URLs.  It is used in the
default values of the variables above.

@item gnus-article-button-face
@vindex gnus-article-button-face
Face used on buttons.

@item gnus-article-mouse-face
@vindex gnus-article-mouse-face
Face used when the mouse cursor is over a button.

@end table

@xref{Customizing Articles}, for how to buttonize articles automatically.


@node Article Date
@subsection Article Date

The date is most likely generated in some obscure timezone you've never
heard of, so it's quite nice to be able to find out what the time was
when the article was sent.

@table @kbd

@item W T u
@kindex W T u (Summary)
@findex gnus-article-date-ut
Display the date in UT (aka. GMT, aka ZULU)
(@code{gnus-article-date-ut}).

@item W T i
@kindex W T i (Summary)
@findex gnus-article-date-iso8601
@cindex ISO 8601
Display the date in international format, aka. ISO 8601
(@code{gnus-article-date-iso8601}).

@item W T l
@kindex W T l (Summary)
@findex gnus-article-date-local
Display the date in the local timezone (@code{gnus-article-date-local}).

@item W T s
@kindex W T s (Summary)
@vindex gnus-article-time-format
@findex gnus-article-date-user
@findex format-time-string
Display the date using a user-defined format
(@code{gnus-article-date-user}).  The format is specified by the
@code{gnus-article-time-format} variable, and is a string that's passed
to @code{format-time-string}.  See the documentation of that variable
for a list of possible format specs.

@item W T e
@kindex W T e (Summary)
@findex gnus-article-date-lapsed
@findex gnus-start-date-timer
@findex gnus-stop-date-timer
Say how much time has elapsed between the article was posted and now
(@code{gnus-article-date-lapsed}).  It looks something like:

@example
X-Sent: 9 years, 6 weeks, 4 days, 9 hours, 3 minutes, 28 seconds ago
@end example

The value of @code{gnus-article-date-lapsed-new-header} determines
whether this header will just be added below the old Date one, or will
replace it.

An advantage of using Gnus to read mail is that it converts simple bugs
into wonderful absurdities.

If you want to have this line updated continually, you can put

@lisp
(gnus-start-date-timer)
@end lisp

in your @file{.gnus.el} file, or you can run it off of some hook.  If
you want to stop the timer, you can use the @code{gnus-stop-date-timer}
command.

@item W T o
@kindex W T o (Summary)
@findex gnus-article-date-original
Display the original date (@code{gnus-article-date-original}).  This can
be useful if you normally use some other conversion function and are
worried that it might be doing something totally wrong.  Say, claiming
that the article was posted in 1854.  Although something like that is
@emph{totally} impossible.  Don't you trust me? *titter*

@end table

@xref{Customizing Articles}, for how to display the date in your
preferred format automatically.


@node Article Signature
@subsection Article Signature
@cindex signatures
@cindex article signature

@vindex gnus-signature-separator
Each article is divided into two parts---the head and the body.  The
body can be divided into a signature part and a text part.  The variable
that says what is to be considered a signature is
@code{gnus-signature-separator}.  This is normally the standard
@samp{^-- $} as mandated by son-of-RFC 1036.  However, many people use
non-standard signature separators, so this variable can also be a list
of regular expressions to be tested, one by one.  (Searches are done
from the end of the body towards the beginning.)  One likely value is:

@lisp
(setq gnus-signature-separator
      '("^-- $"         ; The standard
        "^-- *$"        ; A common mangling
        "^-------*$"    ; Many people just use a looong
                        ; line of dashes.  Shame!
        "^ *--------*$" ; Double-shame!
        "^________*$"   ; Underscores are also popular
        "^========*$")) ; Pervert!
@end lisp

The more permissive you are, the more likely it is that you'll get false
positives.

@vindex gnus-signature-limit
@code{gnus-signature-limit} provides a limit to what is considered a
signature when displaying articles.

@enumerate
@item
If it is an integer, no signature may be longer (in characters) than
that integer.
@item
If it is a floating point number, no signature may be longer (in lines)
than that number.
@item
If it is a function, the function will be called without any parameters,
and if it returns @code{nil}, there is no signature in the buffer.
@item
If it is a string, it will be used as a regexp.  If it matches, the text
in question is not a signature.
@end enumerate

This variable can also be a list where the elements may be of the types
listed above.  Here's an example:

@lisp
(setq gnus-signature-limit
      '(200.0 "^---*Forwarded article"))
@end lisp

This means that if there are more than 200 lines after the signature
separator, or the text after the signature separator is matched by
the regular expression @samp{^---*Forwarded article}, then it isn't a
signature after all.


@node Article Miscellania
@subsection Article Miscellania

@table @kbd
@item A t
@kindex A t (Summary)
@findex gnus-article-babel
Translate the article from one language to another
(@code{gnus-article-babel}). 

@end table


@node MIME Commands
@section @sc{mime} Commands
@cindex MIME decoding
@cindex attachments
@cindex viewing attachments

The following commands all understand the numerical prefix.  For
instance, @kbd{3 b} means ``view the third @sc{mime} part''.

@table @kbd
@item b
@itemx K v
@kindex b (Summary)
@kindex K v (Summary)
View the @sc{mime} part.

@item K o
@kindex K o (Summary)
Save the @sc{mime} part.

@item K c
@kindex K c (Summary)
Copy the @sc{mime} part.

@item K e
@kindex K e (Summary)
View the @sc{mime} part externally.

@item K i
@kindex K i (Summary)
View the @sc{mime} part internally.

@item K |
@kindex K | (Summary)
Pipe the @sc{mime} part to an external command.
@end table

The rest of these @sc{mime} commands do not use the numerical prefix in
the same manner:

@table @kbd
@item K b
@kindex K b (Summary)
Make all the @sc{mime} parts have buttons in front of them.  This is
mostly useful if you wish to save (or perform other actions) on inlined
parts.

@item K m
@kindex K m (Summary)
@findex gnus-summary-repair-multipart
Some multipart messages are transmitted with missing or faulty headers.
This command will attempt to ``repair'' these messages so that they can
be viewed in a more pleasant manner
(@code{gnus-summary-repair-multipart}).

@item X m
@kindex X m (Summary)
@findex gnus-summary-save-parts
Save all parts matching a @sc{mime} type to a directory
(@code{gnus-summary-save-parts}).  Understands the process/prefix
convention (@pxref{Process/Prefix}).

@item M-t
@kindex M-t (Summary)
@findex gnus-summary-display-buttonized
Toggle the buttonized display of the article buffer
(@code{gnus-summary-toggle-display-buttonized}).

@item W M w
@kindex W M w (Summary)
Decode RFC 2047-encoded words in the article headers
(@code{gnus-article-decode-mime-words}).

@item W M c
@kindex W M c (Summary)
Decode encoded article bodies as well as charsets
(@code{gnus-article-decode-charset}).

This command looks in the @code{Content-Type} header to determine the
charset.  If there is no such header in the article, you can give it a
prefix, which will prompt for the charset to decode as.  In regional
groups where people post using some common encoding (but do not include
MIME headers), you can set the @code{charset} group/topic parameter to
the required charset (@pxref{Group Parameters}).

@item W M v
@kindex W M v (Summary)
View all the @sc{mime} parts in the current article
(@code{gnus-mime-view-all-parts}).

@end table

Relevant variables:

@table @code
@item gnus-ignored-mime-types
@vindex gnus-ignored-mime-types
This is a list of regexps.  @sc{mime} types that match a regexp from
this list will be completely ignored by Gnus.  The default value is
@code{nil}.

To have all Vcards be ignored, you'd say something like this:

@lisp
(setq gnus-ignored-mime-types
      '("text/x-vcard"))
@end lisp

@item gnus-unbuttonized-mime-types
@vindex gnus-unbuttonized-mime-types
This is a list of regexps.  @sc{mime} types that match a regexp from
this list won't have @sc{mime} buttons inserted unless they aren't
displayed.  The default value is @code{(".*/.*")}.

@item gnus-article-mime-part-function
@vindex gnus-article-mime-part-function
For each @sc{mime} part, this function will be called with the @sc{mime}
handle as the parameter.  The function is meant to be used to allow
users to gather information from the article (e. g., add Vcard info to
the bbdb database) or to do actions based on parts (e. g., automatically
save all jpegs into some directory).

Here's an example function the does the latter:

@lisp
(defun my-save-all-jpeg-parts (handle)
  (when (equal (car (mm-handle-type handle)) "image/jpeg")
    (with-temp-buffer
      (insert (mm-get-part handle))
      (write-region (point-min) (point-max)
                    (read-file-name "Save jpeg to: ")))))
(setq gnus-article-mime-part-function
      'my-save-all-jpeg-parts)
@end lisp

@vindex gnus-mime-multipart-functions
@item gnus-mime-multipart-functions
Alist of @sc{mime} multipart types and functions to handle them.

@end table


@node Charsets
@section Charsets
@cindex charsets

People use different charsets, and we have @sc{mime} to let us know what
charsets they use.  Or rather, we wish we had.  Many people use
newsreaders and mailers that do not understand or use @sc{mime}, and
just send out messages without saying what character sets they use.  To
help a bit with this, some local news hierarchies have policies that say
what character set is the default.  For instance, the @samp{fj}
hierarchy uses @code{iso-2022-jp-2}.

@vindex gnus-group-charset-alist
This knowledge is encoded in the @code{gnus-group-charset-alist}
variable, which is an alist of regexps (to match group names) and
default charsets to be used when reading these groups.

In addition, some people do use soi-disant @sc{mime}-aware agents that
aren't.  These blitely mark messages as being in @code{iso-8859-1} even
if they really are in @code{koi-8}.  To help here, the
@code{gnus-newsgroup-ignored-charsets} variable can be used.  The
charsets that are listed here will be ignored.  The variable can be set
on a group-by-group basis using the group parameters (@pxref{Group
Parameters}).  The default value is @code{(unknown-8bit)}, which is
something some agents insist on having in there.

@vindex gnus-group-posting-charset-alist
When posting, @code{gnus-group-posting-charset-alist} is used to
determine which charsets should not be encoded using the @sc{mime}
encodings.  For instance, some hierarchies discourage using
quoted-printable header encoding.

This variable is an alist of regexps and permitted unencoded charsets
for posting.  Each element of the alist has the form @code{(}@var{test
header body-list}@code{)}, where:

@table @var
@item test
is either a regular expression matching the newsgroup header or a
variable to query,
@item header
is the charset which may be left unencoded in the header (@code{nil}
means encode all charsets),
@item body-list
is a list of charsets which may be encoded using 8bit content-transfer
encoding in the body, or one of the special values @code{nil} (always
encode using quoted-printable) or @code{t} (always use 8bit).
@end table

@cindex Russian
@cindex koi8-r
@cindex koi8-u
@cindex iso-8859-5
@cindex coding system aliases
@cindex preferred charset

Other charset tricks that may be useful, although not Gnus-specific:

If there are several @sc{mime} charsets that encode the same Emacs
charset, you can choose what charset to use by saying the following:

@lisp
(put-charset-property 'cyrillic-iso8859-5
                      'preferred-coding-system 'koi8-r)
@end lisp

This means that Russian will be encoded using @code{koi8-r} instead of
the default @code{iso-8859-5} @sc{mime} charset.

If you want to read messages in @code{koi8-u}, you can cheat and say

@lisp
(define-coding-system-alias 'koi8-u 'koi8-r)
@end lisp

This will almost do the right thing.

And finally, to read charsets like @code{windows-1251}, you can say
something like

@lisp
(codepage-setup 1251)
(define-coding-system-alias 'windows-1251 'cp1251)
@end lisp


@node Article Commands
@section Article Commands

@table @kbd

@item A P
@cindex PostScript
@cindex printing
@kindex A P (Summary)
@vindex gnus-ps-print-hook
@findex gnus-summary-print-article
Generate and print a PostScript image of the article buffer
(@code{gnus-summary-print-article}).  @code{gnus-ps-print-hook} will be
run just before printing the buffer.

@end table


@node Summary Sorting
@section Summary Sorting
@cindex summary sorting

You can have the summary buffer sorted in various ways, even though I
can't really see why you'd want that.

@table @kbd

@item C-c C-s C-n
@kindex C-c C-s C-n (Summary)
@findex gnus-summary-sort-by-number
Sort by article number (@code{gnus-summary-sort-by-number}).

@item C-c C-s C-a
@kindex C-c C-s C-a (Summary)
@findex gnus-summary-sort-by-author
Sort by author (@code{gnus-summary-sort-by-author}).

@item C-c C-s C-s
@kindex C-c C-s C-s (Summary)
@findex gnus-summary-sort-by-subject
Sort by subject (@code{gnus-summary-sort-by-subject}).

@item C-c C-s C-d
@kindex C-c C-s C-d (Summary)
@findex gnus-summary-sort-by-date
Sort by date (@code{gnus-summary-sort-by-date}).

@item C-c C-s C-l
@kindex C-c C-s C-l (Summary)
@findex gnus-summary-sort-by-lines
Sort by lines (@code{gnus-summary-sort-by-lines}).

@item C-c C-s C-c
@kindex C-c C-s C-c (Summary)
@findex gnus-summary-sort-by-chars
Sort by article length (@code{gnus-summary-sort-by-chars}).

@item C-c C-s C-i
@kindex C-c C-s C-i (Summary)
@findex gnus-summary-sort-by-score
Sort by score (@code{gnus-summary-sort-by-score}).
@end table

These functions will work both when you use threading and when you don't
use threading.  In the latter case, all summary lines will be sorted,
line by line.  In the former case, sorting will be done on a
root-by-root basis, which might not be what you were looking for.  To
toggle whether to use threading, type @kbd{T T} (@pxref{Thread
Commands}).


@node Finding the Parent
@section Finding the Parent
@cindex parent articles
@cindex referring articles

@table @kbd
@item ^
@kindex ^ (Summary)
@findex gnus-summary-refer-parent-article
If you'd like to read the parent of the current article, and it is not
displayed in the summary buffer, you might still be able to.  That is,
if the current group is fetched by @sc{nntp}, the parent hasn't expired
and the @code{References} in the current article are not mangled, you
can just press @kbd{^} or @kbd{A r}
(@code{gnus-summary-refer-parent-article}).  If everything goes well,
you'll get the parent.  If the parent is already displayed in the
summary buffer, point will just move to this article.

If given a positive numerical prefix, fetch that many articles back into
the ancestry.  If given a negative numerical prefix, fetch just that
ancestor.  So if you say @kbd{3 ^}, Gnus will fetch the parent, the
grandparent and the grandgrandparent of the current article.  If you say
@kbd{-3 ^}, Gnus will only fetch the grandgrandparent of the current
article.

@item A R (Summary)
@findex gnus-summary-refer-references
@kindex A R (Summary)
Fetch all articles mentioned in the @code{References} header of the
article (@code{gnus-summary-refer-references}).

@item A T (Summary)
@findex gnus-summary-refer-thread
@kindex A T (Summary)
Display the full thread where the current article appears
(@code{gnus-summary-refer-thread}).  This command has to fetch all the
headers in the current group to work, so it usually takes a while.  If
you do it often, you may consider setting @code{gnus-fetch-old-headers}
to @code{invisible} (@pxref{Filling In Threads}).  This won't have any
visible effects normally, but it'll make this command work a whole lot
faster.  Of course, it'll make group entry somewhat slow.

@vindex gnus-refer-thread-limit
The @code{gnus-refer-thread-limit} variable says how many old (i. e.,
articles before the first displayed in the current group) headers to
fetch when doing this command.  The default is 200.  If @code{t}, all
the available headers will be fetched.  This variable can be overridden
by giving the @kbd{A T} command a numerical prefix.

@item M-^ (Summary)
@findex gnus-summary-refer-article
@kindex M-^ (Summary)
@cindex Message-ID
@cindex fetching by Message-ID
You can also ask the @sc{nntp} server for an arbitrary article, no
matter what group it belongs to.  @kbd{M-^}
(@code{gnus-summary-refer-article}) will ask you for a
@code{Message-ID}, which is one of those long, hard-to-read thingies
that look something like @samp{<38o6up$6f2@@hymir.ifi.uio.no>}.  You
have to get it all exactly right.  No fuzzy searches, I'm afraid.
@end table

The current select method will be used when fetching by
@code{Message-ID} from non-news select method, but you can override this
by giving this command a prefix.

@vindex gnus-refer-article-method
If the group you are reading is located on a backend that does not
support fetching by @code{Message-ID} very well (like @code{nnspool}),
you can set @code{gnus-refer-article-method} to an @sc{nntp} method.  It
would, perhaps, be best if the @sc{nntp} server you consult is the one
updating the spool you are reading from, but that's not really
necessary.

It can also be a list of select methods, as well as the special symbol
@code{current}, which means to use the current select method.  If it
is a list, Gnus will try all the methods in the list until it finds a
match.

Here's an example setting that will first try the current method, and
then ask Deja if that fails:

@lisp
(setq gnus-refer-article-method
      '(current
        (nnweb "refer" (nnweb-type dejanews))))
@end lisp

Most of the mail backends support fetching by @code{Message-ID}, but do
not do a particularly excellent job at it.  That is, @code{nnmbox} and
@code{nnbabyl} are able to locate articles from any groups, while
@code{nnml} and @code{nnfolder} are only able to locate articles that
have been posted to the current group.  (Anything else would be too time
consuming.)  @code{nnmh} does not support this at all.


@node Alternative Approaches
@section Alternative Approaches

Different people like to read news using different methods.  This being
Gnus, we offer a small selection of minor modes for the summary buffers.

@menu
* Pick and Read::               First mark articles and then read them.
* Binary Groups::               Auto-decode all articles.
@end menu


@node Pick and Read
@subsection Pick and Read
@cindex pick and read

Some newsreaders (like @code{nn} and, uhm, @code{Netnews} on VM/CMS) use
a two-phased reading interface.  The user first marks in a summary
buffer the articles she wants to read.  Then she starts reading the
articles with just an article buffer displayed.

@findex gnus-pick-mode
@kindex M-x gnus-pick-mode
Gnus provides a summary buffer minor mode that allows
this---@code{gnus-pick-mode}.  This basically means that a few process
mark commands become one-keystroke commands to allow easy marking, and
it provides one additional command for switching to the summary buffer.

Here are the available keystrokes when using pick mode:

@table @kbd
@item .
@kindex . (Pick)
@findex gnus-pick-article-or-thread
Pick the article or thread on the current line
(@code{gnus-pick-article-or-thread}).  If the variable
@code{gnus-thread-hide-subtree} is true, then this key selects the
entire thread when used at the first article of the thread.  Otherwise,
it selects just the article.  If given a numerical prefix, go to that
thread or article and pick it.  (The line number is normally displayed
at the beginning of the summary pick lines.)

@item SPACE
@kindex SPACE (Pick)
@findex gnus-pick-next-page
Scroll the summary buffer up one page (@code{gnus-pick-next-page}).  If
at the end of the buffer, start reading the picked articles.

@item u
@kindex u (Pick)
@findex gnus-pick-unmark-article-or-thread.
Unpick the thread or article
(@code{gnus-pick-unmark-article-or-thread}).  If the variable
@code{gnus-thread-hide-subtree} is true, then this key unpicks the
thread if used at the first article of the thread.  Otherwise it unpicks
just the article.  You can give this key a numerical prefix to unpick
the thread or article at that line.

@item RET
@kindex RET (Pick)
@findex gnus-pick-start-reading
@vindex gnus-pick-display-summary
Start reading the picked articles (@code{gnus-pick-start-reading}).  If
given a prefix, mark all unpicked articles as read first.  If
@code{gnus-pick-display-summary} is non-@code{nil}, the summary buffer
will still be visible when you are reading.

@end table

All the normal summary mode commands are still available in the
pick-mode, with the exception of @kbd{u}.  However @kbd{!} is available
which is mapped to the same function
@code{gnus-summary-tick-article-forward}.

If this sounds like a good idea to you, you could say:

@lisp
(add-hook 'gnus-summary-mode-hook 'gnus-pick-mode)
@end lisp

@vindex gnus-pick-mode-hook
@code{gnus-pick-mode-hook} is run in pick minor mode buffers.

@vindex gnus-mark-unpicked-articles-as-read
If @code{gnus-mark-unpicked-articles-as-read} is non-@code{nil}, mark
all unpicked articles as read.  The default is @code{nil}.

@vindex gnus-summary-pick-line-format
The summary line format in pick mode is slightly different from the
standard format.  At the beginning of each line the line number is
displayed.  The pick mode line format is controlled by the
@code{gnus-summary-pick-line-format} variable (@pxref{Formatting
Variables}).  It accepts the same format specs that
@code{gnus-summary-line-format} does (@pxref{Summary Buffer Lines}).


@node Binary Groups
@subsection Binary Groups
@cindex binary groups

@findex gnus-binary-mode
@kindex M-x gnus-binary-mode
If you spend much time in binary groups, you may grow tired of hitting
@kbd{X u}, @kbd{n}, @kbd{RET} all the time.  @kbd{M-x gnus-binary-mode}
is a minor mode for summary buffers that makes all ordinary Gnus article
selection functions uudecode series of articles and display the result
instead of just displaying the articles the normal way.

@kindex g (Binary)
@findex gnus-binary-show-article
The only way, in fact, to see the actual articles is the @kbd{g}
command, when you have turned on this mode
(@code{gnus-binary-show-article}).

@vindex gnus-binary-mode-hook
@code{gnus-binary-mode-hook} is called in binary minor mode buffers.


@node Tree Display
@section Tree Display
@cindex trees

@vindex gnus-use-trees
If you don't like the normal Gnus summary display, you might try setting
@code{gnus-use-trees} to @code{t}.  This will create (by default) an
additional @dfn{tree buffer}.  You can execute all summary mode commands
in the tree buffer.

There are a few variables to customize the tree display, of course:

@table @code
@item gnus-tree-mode-hook
@vindex gnus-tree-mode-hook
A hook called in all tree mode buffers.

@item gnus-tree-mode-line-format
@vindex gnus-tree-mode-line-format
A format string for the mode bar in the tree mode buffers (@pxref{Mode
Line Formatting}).  The default is @samp{Gnus: %%b %S %Z}.  For a list
of valid specs, @pxref{Summary Buffer Mode Line}.

@item gnus-selected-tree-face
@vindex gnus-selected-tree-face
Face used for highlighting the selected article in the tree buffer.  The
default is @code{modeline}.

@item gnus-tree-line-format
@vindex gnus-tree-line-format
A format string for the tree nodes.  The name is a bit of a misnomer,
though---it doesn't define a line, but just the node.  The default value
is @samp{%(%[%3,3n%]%)}, which displays the first three characters of
the name of the poster.  It is vital that all nodes are of the same
length, so you @emph{must} use @samp{%4,4n}-like specifiers.

Valid specs are:

@table @samp
@item n
The name of the poster.
@item f
The @code{From} header.
@item N
The number of the article.
@item [
The opening bracket.
@item ]
The closing bracket.
@item s
The subject.
@end table

@xref{Formatting Variables}.

Variables related to the display are:

@table @code
@item gnus-tree-brackets
@vindex gnus-tree-brackets
This is used for differentiating between ``real'' articles and
``sparse'' articles.  The format is @code{((@var{real-open} . @var{real-close})
(@var{sparse-open} . @var{sparse-close}) (@var{dummy-open} . @var{dummy-close}))}, and the
default is @code{((?[ . ?]) (?( . ?)) (?@{ . ?@}) (?< . ?>))}.

@item gnus-tree-parent-child-edges
@vindex gnus-tree-parent-child-edges
This is a list that contains the characters used for connecting parent
nodes to their children.  The default is @code{(?- ?\\ ?|)}.

@end table

@item gnus-tree-minimize-window
@vindex gnus-tree-minimize-window
If this variable is non-@code{nil}, Gnus will try to keep the tree
buffer as small as possible to allow more room for the other Gnus
windows.  If this variable is a number, the tree buffer will never be
higher than that number.  The default is @code{t}.  Note that if you
have several windows displayed side-by-side in a frame and the tree
buffer is one of these, minimizing the tree window will also resize all
other windows displayed next to it.

@item gnus-generate-tree-function
@vindex gnus-generate-tree-function
@findex gnus-generate-horizontal-tree
@findex gnus-generate-vertical-tree
The function that actually generates the thread tree.  Two predefined
functions are available: @code{gnus-generate-horizontal-tree} and
@code{gnus-generate-vertical-tree} (which is the default).

@end table

Here's an example from a horizontal tree buffer:

@example
@{***@}-(***)-[odd]-[Gun]
     |      \[Jan]
     |      \[odd]-[Eri]
     |      \(***)-[Eri]
     |            \[odd]-[Paa]
     \[Bjo]
     \[Gun]
     \[Gun]-[Jor]
@end example

Here's the same thread displayed in a vertical tree buffer:

@example
@{***@}
  |--------------------------\-----\-----\
(***)                         [Bjo] [Gun] [Gun]
  |--\-----\-----\                          |
[odd] [Jan] [odd] (***)                   [Jor]
  |           |     |--\
[Gun]       [Eri] [Eri] [odd]
                          |
                        [Paa]
@end example

If you're using horizontal trees, it might be nice to display the trees
side-by-side with the summary buffer.  You could add something like the
following to your @file{.gnus.el} file:

@lisp
(setq gnus-use-trees t
      gnus-generate-tree-function 'gnus-generate-horizontal-tree
      gnus-tree-minimize-window nil)
(gnus-add-configuration
 '(article
   (vertical 1.0
             (horizontal 0.25
                         (summary 0.75 point)
                         (tree 1.0))
             (article 1.0))))
@end lisp

@xref{Windows Configuration}.


@node Mail Group Commands
@section Mail Group Commands
@cindex mail group commands

Some commands only make sense in mail groups.  If these commands are
invalid in the current group, they will raise a hell and let you know.

All these commands (except the expiry and edit commands) use the
process/prefix convention (@pxref{Process/Prefix}).

@table @kbd

@item B e
@kindex B e (Summary)
@findex gnus-summary-expire-articles
Expire all expirable articles in the group
(@code{gnus-summary-expire-articles}).

@item B M-C-e
@kindex B M-C-e (Summary)
@findex gnus-summary-expire-articles-now
Delete all the expirable articles in the group
(@code{gnus-summary-expire-articles-now}).  This means that @strong{all}
articles eligible for expiry in the current group will
disappear forever into that big @file{/dev/null} in the sky.

@item B DEL
@kindex B DEL (Summary)
@findex gnus-summary-delete-article
@c @icon{gnus-summary-mail-delete}
Delete the mail article.  This is ``delete'' as in ``delete it from your
disk forever and ever, never to return again.'' Use with caution.
(@code{gnus-summary-delete-article}).

@item B m
@kindex B m (Summary)
@cindex move mail
@findex gnus-summary-move-article
@vindex gnus-preserve-marks
Move the article from one mail group to another
(@code{gnus-summary-move-article}).  Marks will be preserved if
@var{gnus-preserve-marks} is non-@code{nil} (which is the default). 

@item B c
@kindex B c (Summary)
@cindex copy mail
@findex gnus-summary-copy-article
@c @icon{gnus-summary-mail-copy}
Copy the article from one group (mail group or not) to a mail group
(@code{gnus-summary-copy-article}).  Marks will be preserved if
@var{gnus-preserve-marks} is non-@code{nil} (which is the default).

@item B B
@kindex B B (Summary)
@cindex crosspost mail
@findex gnus-summary-crosspost-article
Crosspost the current article to some other group
(@code{gnus-summary-crosspost-article}).  This will create a new copy of
the article in the other group, and the Xref headers of the article will
be properly updated.

@item B i
@kindex B i (Summary)
@findex gnus-summary-import-article
Import an arbitrary file into the current mail newsgroup
(@code{gnus-summary-import-article}).  You will be prompted for a file
name, a @code{From} header and a @code{Subject} header.

@item B r
@kindex B r (Summary)
@findex gnus-summary-respool-article
Respool the mail article (@code{gnus-summary-respool-article}).
@code{gnus-summary-respool-default-method} will be used as the default
select method when respooling.  This variable is @code{nil} by default,
which means that the current group select method will be used instead.
Marks will be preserved if @var{gnus-preserve-marks} is non-@code{nil}
(which is the default).

@item B w
@itemx e
@kindex B w (Summary)
@kindex e (Summary)
@findex gnus-summary-edit-article
@kindex C-c C-c (Article)
Edit the current article (@code{gnus-summary-edit-article}).  To finish
editing and make the changes permanent, type @kbd{C-c C-c}
(@kbd{gnus-summary-edit-article-done}).  If you give a prefix to the
@kbd{C-c C-c} command, Gnus won't re-highlight the article.

@item B q
@kindex B q (Summary)
@findex gnus-summary-respool-query
If you want to re-spool an article, you might be curious as to what group
the article will end up in before you do the re-spooling.  This command
will tell you (@code{gnus-summary-respool-query}).

@item B t
@kindex B t (Summary)
@findex gnus-summary-respool-trace
Similarly, this command will display all fancy splitting patterns used
when repooling, if any (@code{gnus-summary-respool-trace}).

@item B p
@kindex B p (Summary)
@findex gnus-summary-article-posted-p
Some people have a tendency to send you "courtesy" copies when they
follow up to articles you have posted.  These usually have a
@code{Newsgroups} header in them, but not always.  This command
(@code{gnus-summary-article-posted-p}) will try to fetch the current
article from your news server (or rather, from
@code{gnus-refer-article-method} or @code{gnus-select-method}) and will
report back whether it found the article or not.  Even if it says that
it didn't find the article, it may have been posted anyway---mail
propagation is much faster than news propagation, and the news copy may
just not have arrived yet.

@end table

@vindex gnus-move-split-methods
@cindex moving articles
If you move (or copy) articles regularly, you might wish to have Gnus
suggest where to put the articles.  @code{gnus-move-split-methods} is a
variable that uses the same syntax as @code{gnus-split-methods}
(@pxref{Saving Articles}).  You may customize that variable to create
suggestions you find reasonable.  (Note that
@code{gnus-move-split-methods} uses group names where
@code{gnus-split-methods} uses file names.)

@lisp
(setq gnus-move-split-methods
      '(("^From:.*Lars Magne" "nnml:junk")
        ("^Subject:.*gnus" "nnfolder:important")
        (".*" "nnml:misc")))
@end lisp


@node Various Summary Stuff
@section Various Summary Stuff

@menu
* Summary Group Information::         Information oriented commands.
* Searching for Articles::            Multiple article commands.
* Summary Generation Commands::       (Re)generating the summary buffer.
* Really Various Summary Commands::   Those pesky non-conformant commands.
@end menu

@table @code
@vindex gnus-summary-mode-hook
@item gnus-summary-mode-hook
This hook is called when creating a summary mode buffer.

@vindex gnus-summary-generate-hook
@item gnus-summary-generate-hook
This is called as the last thing before doing the threading and the
generation of the summary buffer.  It's quite convenient for customizing
the threading variables based on what data the newsgroup has.  This hook
is called from the summary buffer after most summary buffer variables
have been set.

@vindex gnus-summary-prepare-hook
@item gnus-summary-prepare-hook
It is called after the summary buffer has been generated.  You might use
it to, for instance, highlight lines or modify the look of the buffer in
some other ungodly manner.  I don't care.

@vindex gnus-summary-prepared-hook
@item gnus-summary-prepared-hook
A hook called as the very last thing after the summary buffer has been
generated.

@vindex gnus-summary-ignore-duplicates
@item gnus-summary-ignore-duplicates
When Gnus discovers two articles that have the same @code{Message-ID},
it has to do something drastic.  No articles are allowed to have the
same @code{Message-ID}, but this may happen when reading mail from some
sources.  Gnus allows you to customize what happens with this variable.
If it is @code{nil} (which is the default), Gnus will rename the
@code{Message-ID} (for display purposes only) and display the article as
any other article.  If this variable is @code{t}, it won't display the
article---it'll be as if it never existed.

@vindex gnus-alter-articles-to-read-function
@item gnus-alter-articles-to-read-function
This function, which takes two parameters (the group name and the list
of articles to be selected), is called to allow the user to alter the
list of articles to be selected.

For instance, the following function adds the list of cached articles to
the list in one particular group:

@lisp
(defun my-add-cached-articles (group articles)
  (if (string= group "some.group")
      (append gnus-newsgroup-cached articles)
    articles))
@end lisp

@end table


@node Summary Group Information
@subsection Summary Group Information

@table @kbd

@item H f
@kindex H f (Summary)
@findex gnus-summary-fetch-faq
@vindex gnus-group-faq-directory
Try to fetch the FAQ (list of frequently asked questions) for the
current group (@code{gnus-summary-fetch-faq}).  Gnus will try to get the
FAQ from @code{gnus-group-faq-directory}, which is usually a directory
on a remote machine.  This variable can also be a list of directories.
In that case, giving a prefix to this command will allow you to choose
between the various sites.  @code{ange-ftp} or @code{efs} will probably
be used for fetching the file.

@item H d
@kindex H d (Summary)
@findex gnus-summary-describe-group
Give a brief description of the current group
(@code{gnus-summary-describe-group}).  If given a prefix, force
rereading the description from the server.

@item H h
@kindex H h (Summary)
@findex gnus-summary-describe-briefly
Give an extremely brief description of the most important summary
keystrokes (@code{gnus-summary-describe-briefly}).

@item H i
@kindex H i (Summary)
@findex gnus-info-find-node
Go to the Gnus info node (@code{gnus-info-find-node}).
@end table


@node Searching for Articles
@subsection Searching for Articles

@table @kbd

@item M-s
@kindex M-s (Summary)
@findex gnus-summary-search-article-forward
Search through all subsequent articles for a regexp
(@code{gnus-summary-search-article-forward}).

@item M-r
@kindex M-r (Summary)
@findex gnus-summary-search-article-backward
Search through all previous articles for a regexp
(@code{gnus-summary-search-article-backward}).

@item &
@kindex & (Summary)
@findex gnus-summary-execute-command
This command will prompt you for a header, a regular expression to match
on this field, and a command to be executed if the match is made
(@code{gnus-summary-execute-command}).  If the header is an empty
string, the match is done on the entire article.  If given a prefix,
search backward instead.

For instance, @kbd{& RET some.*string #} will put the process mark on
all articles that have heads or bodies that match @samp{some.*string}.

@item M-&
@kindex M-& (Summary)
@findex gnus-summary-universal-argument
Perform any operation on all articles that have been marked with
the process mark (@code{gnus-summary-universal-argument}).
@end table

@node Summary Generation Commands
@subsection Summary Generation Commands

@table @kbd

@item Y g
@kindex Y g (Summary)
@findex gnus-summary-prepare
Regenerate the current summary buffer (@code{gnus-summary-prepare}).

@item Y c
@kindex Y c (Summary)
@findex gnus-summary-insert-cached-articles
Pull all cached articles (for the current group) into the summary buffer
(@code{gnus-summary-insert-cached-articles}).

@end table


@node Really Various Summary Commands
@subsection Really Various Summary Commands

@table @kbd

@item A D
@itemx C-d
@kindex C-d (Summary)
@kindex A D (Summary)
@findex gnus-summary-enter-digest-group
If the current article is a collection of other articles (for instance,
a digest), you might use this command to enter a group based on the that
article (@code{gnus-summary-enter-digest-group}).  Gnus will try to
guess what article type is currently displayed unless you give a prefix
to this command, which forces a ``digest'' interpretation.  Basically,
whenever you see a message that is a collection of other messages of
some format, you @kbd{C-d} and read these messages in a more convenient
fashion.

@item M-C-d
@kindex M-C-d (Summary)
@findex gnus-summary-read-document
This command is very similar to the one above, but lets you gather
several documents into one biiig group
(@code{gnus-summary-read-document}).  It does this by opening several
@code{nndoc} groups for each document, and then opening an
@code{nnvirtual} group on top of these @code{nndoc} groups.  This
command understands the process/prefix convention
(@pxref{Process/Prefix}).

@item C-t
@kindex C-t (Summary)
@findex gnus-summary-toggle-truncation
Toggle truncation of summary lines
(@code{gnus-summary-toggle-truncation}).  This will probably confuse the
line centering function in the summary buffer, so it's not a good idea
to have truncation switched off while reading articles.

@item =
@kindex = (Summary)
@findex gnus-summary-expand-window
Expand the summary buffer window (@code{gnus-summary-expand-window}).
If given a prefix, force an @code{article} window configuration.

@item M-C-e
@kindex M-C-e (Summary)
@findex gnus-summary-edit-parameters
Edit the group parameters (@pxref{Group Parameters}) of the current
group (@code{gnus-summary-edit-parameters}).

@item M-C-a
@kindex M-C-a (Summary)
@findex gnus-summary-customize-parameters
Customize the group parameters (@pxref{Group Parameters}) of the current
group (@code{gnus-summary-customize-parameters}).

@end table


@node Exiting the Summary Buffer
@section Exiting the Summary Buffer
@cindex summary exit
@cindex exiting groups

Exiting from the summary buffer will normally update all info on the
group and return you to the group buffer.

@table @kbd

@item Z Z
@itemx q
@kindex Z Z (Summary)
@kindex q (Summary)
@findex gnus-summary-exit
@vindex gnus-summary-exit-hook
@vindex gnus-summary-prepare-exit-hook
@c @icon{gnus-summary-exit}
Exit the current group and update all information on the group
(@code{gnus-summary-exit}).  @code{gnus-summary-prepare-exit-hook} is
called before doing much of the exiting, which calls
@code{gnus-summary-expire-articles} by default.
@code{gnus-summary-exit-hook} is called after finishing the exit
process.  @code{gnus-group-no-more-groups-hook} is run when returning to
group mode having no more (unread) groups.

@item Z E
@itemx Q
@kindex Z E (Summary)
@kindex Q (Summary)
@findex gnus-summary-exit-no-update
Exit the current group without updating any information on the group
(@code{gnus-summary-exit-no-update}).

@item Z c
@itemx c
@kindex Z c (Summary)
@kindex c (Summary)
@findex gnus-summary-catchup-and-exit
@c @icon{gnus-summary-catchup-and-exit}
Mark all unticked articles in the group as read and then exit
(@code{gnus-summary-catchup-and-exit}).

@item Z C
@kindex Z C (Summary)
@findex gnus-summary-catchup-all-and-exit
Mark all articles, even the ticked ones, as read and then exit
(@code{gnus-summary-catchup-all-and-exit}).

@item Z n
@kindex Z n (Summary)
@findex gnus-summary-catchup-and-goto-next-group
Mark all articles as read and go to the next group
(@code{gnus-summary-catchup-and-goto-next-group}).

@item Z R
@kindex Z R (Summary)
@findex gnus-summary-reselect-current-group
Exit this group, and then enter it again
(@code{gnus-summary-reselect-current-group}).  If given a prefix, select
all articles, both read and unread.

@item Z G
@itemx M-g
@kindex Z G (Summary)
@kindex M-g (Summary)
@findex gnus-summary-rescan-group
@c @icon{gnus-summary-mail-get}
Exit the group, check for new articles in the group, and select the
group (@code{gnus-summary-rescan-group}).  If given a prefix, select all
articles, both read and unread.

@item Z N
@kindex Z N (Summary)
@findex gnus-summary-next-group
Exit the group and go to the next group
(@code{gnus-summary-next-group}).

@item Z P
@kindex Z P (Summary)
@findex gnus-summary-prev-group
Exit the group and go to the previous group
(@code{gnus-summary-prev-group}).

@item Z s
@kindex Z s (Summary)
@findex gnus-summary-save-newsrc
Save the current number of read/marked articles in the dribble buffer
and then save the dribble buffer (@code{gnus-summary-save-newsrc}).  If
given a prefix, also save the @file{.newsrc} file(s).  Using this
command will make exit without updating (the @kbd{Q} command) worthless.
@end table

@vindex gnus-exit-group-hook
@code{gnus-exit-group-hook} is called when you exit the current group
with an ``updating'' exit.  For instance @kbd{Q}
(@code{gnus-summary-exit-no-update}) does not call this hook.

@findex gnus-summary-wake-up-the-dead
@findex gnus-dead-summary-mode
@vindex gnus-kill-summary-on-exit
If you're in the habit of exiting groups, and then changing your mind
about it, you might set @code{gnus-kill-summary-on-exit} to @code{nil}.
If you do that, Gnus won't kill the summary buffer when you exit it.
(Quelle surprise!)  Instead it will change the name of the buffer to
something like @samp{*Dead Summary ... *} and install a minor mode
called @code{gnus-dead-summary-mode}.  Now, if you switch back to this
buffer, you'll find that all keys are mapped to a function called
@code{gnus-summary-wake-up-the-dead}.  So tapping any keys in a dead
summary buffer will result in a live, normal summary buffer.

There will never be more than one dead summary buffer at any one time.

@vindex gnus-use-cross-reference
The data on the current group will be updated (which articles you have
read, which articles you have replied to, etc.) when you exit the
summary buffer.  If the @code{gnus-use-cross-reference} variable is
@code{t} (which is the default), articles that are cross-referenced to
this group and are marked as read, will also be marked as read in the
other subscribed groups they were cross-posted to.  If this variable is
neither @code{nil} nor @code{t}, the article will be marked as read in
both subscribed and unsubscribed groups (@pxref{Crosspost Handling}).


@node Crosspost Handling
@section Crosspost Handling

@cindex velveeta
@cindex spamming
Marking cross-posted articles as read ensures that you'll never have to
read the same article more than once.  Unless, of course, somebody has
posted it to several groups separately.  Posting the same article to
several groups (not cross-posting) is called @dfn{spamming}, and you are
by law required to send nasty-grams to anyone who perpetrates such a
heinous crime.  You may want to try NoCeM handling to filter out spam
(@pxref{NoCeM}).

Remember: Cross-posting is kinda ok, but posting the same article
separately to several groups is not.  Massive cross-posting (aka.
@dfn{velveeta}) is to be avoided at all costs, and you can even use the
@code{gnus-summary-mail-crosspost-complaint} command to complain about
excessive crossposting (@pxref{Summary Mail Commands}).

@cindex cross-posting
@cindex Xref
@cindex @sc{nov}
One thing that may cause Gnus to not do the cross-posting thing
correctly is if you use an @sc{nntp} server that supports @sc{xover}
(which is very nice, because it speeds things up considerably) which
does not include the @code{Xref} header in its @sc{nov} lines.  This is
Evil, but all too common, alas, alack.  Gnus tries to Do The Right Thing
even with @sc{xover} by registering the @code{Xref} lines of all
articles you actually read, but if you kill the articles, or just mark
them as read without reading them, Gnus will not get a chance to snoop
the @code{Xref} lines out of these articles, and will be unable to use
the cross reference mechanism.

@cindex LIST overview.fmt
@cindex overview.fmt
To check whether your @sc{nntp} server includes the @code{Xref} header
in its overview files, try @samp{telnet your.nntp.server nntp},
@samp{MODE READER} on @code{inn} servers, and then say @samp{LIST
overview.fmt}.  This may not work, but if it does, and the last line you
get does not read @samp{Xref:full}, then you should shout and whine at
your news admin until she includes the @code{Xref} header in the
overview files.

@vindex gnus-nov-is-evil
If you want Gnus to get the @code{Xref}s right all the time, you have to
set @code{gnus-nov-is-evil} to @code{t}, which slows things down
considerably.

C'est la vie.

For an alternative approach, @pxref{Duplicate Suppression}.


@node Duplicate Suppression
@section Duplicate Suppression

By default, Gnus tries to make sure that you don't have to read the same
article more than once by utilizing the crossposting mechanism
(@pxref{Crosspost Handling}).  However, that simple and efficient
approach may not work satisfactory for some users for various
reasons.

@enumerate
@item
The @sc{nntp} server may fail to generate the @code{Xref} header.  This
is evil and not very common.

@item
The @sc{nntp} server may fail to include the @code{Xref} header in the
@file{.overview} data bases.  This is evil and all too common, alas.

@item
You may be reading the same group (or several related groups) from
different @sc{nntp} servers.

@item
You may be getting mail that duplicates articles posted to groups.
@end enumerate

I'm sure there are other situations where @code{Xref} handling fails as
well, but these four are the most common situations.

If, and only if, @code{Xref} handling fails for you, then you may
consider switching on @dfn{duplicate suppression}.  If you do so, Gnus
will remember the @code{Message-ID}s of all articles you have read or
otherwise marked as read, and then, as if by magic, mark them as read
all subsequent times you see them---in @emph{all} groups.  Using this
mechanism is quite likely to be somewhat inefficient, but not overly
so.  It's certainly preferable to reading the same articles more than
once.

Duplicate suppression is not a very subtle instrument.  It's more like a
sledge hammer than anything else.  It works in a very simple
fashion---if you have marked an article as read, it adds this Message-ID
to a cache.  The next time it sees this Message-ID, it will mark the
article as read with the @samp{M} mark.  It doesn't care what group it
saw the article in.

@table @code
@item gnus-suppress-duplicates
@vindex gnus-suppress-duplicates
If non-@code{nil}, suppress duplicates.

@item gnus-save-duplicate-list
@vindex gnus-save-duplicate-list
If non-@code{nil}, save the list of duplicates to a file.  This will
make startup and shutdown take longer, so the default is @code{nil}.
However, this means that only duplicate articles read in a single Gnus
session are suppressed.

@item gnus-duplicate-list-length
@vindex gnus-duplicate-list-length
This variable says how many @code{Message-ID}s to keep in the duplicate
suppression list.  The default is 10000.

@item gnus-duplicate-file
@vindex gnus-duplicate-file
The name of the file to store the duplicate suppression list in.  The
default is @file{~/News/suppression}.
@end table

If you have a tendency to stop and start Gnus often, setting
@code{gnus-save-duplicate-list} to @code{t} is probably a good idea.  If
you leave Gnus running for weeks on end, you may have it @code{nil}.  On
the other hand, saving the list makes startup and shutdown much slower,
so that means that if you stop and start Gnus often, you should set
@code{gnus-save-duplicate-list} to @code{nil}.  Uhm.  I'll leave this up
to you to figure out, I think.

@node Security
@section Security

Gnus is able to verify PGP or S/MIME signed messages or decrypt PGP
encrypted messages.

@enumerate
@item 
To verify or decrypt PGP messages, you have to install mailcrypt or
gpg.el.

@end enumerate

@table @code
@item mm-verify-option
@vindex mm-verify-option
Option of verifying signed parts.  @code{never}, not verify;
@code{always}, always verify; @code{known}, only verify known
protocols. Otherwise, ask user.

@item mm-decrypt-option
@vindex mm-decrypt-option
Option of decrypting encrypted parts.  @code{never}, no decryption;
@code{always}, always decrypt @code{known}, only decrypt known
protocols. Otherwise, ask user.

@end table

@node The Article Buffer
@chapter The Article Buffer
@cindex article buffer

The articles are displayed in the article buffer, of which there is only
one.  All the summary buffers share the same article buffer unless you
tell Gnus otherwise.

@menu
* Hiding Headers::        Deciding what headers should be displayed.
* Using MIME::            Pushing articles through @sc{mime} before reading them.
* Customizing Articles::  Tailoring the look of the articles.
* Article Keymap::        Keystrokes available in the article buffer.
* Misc Article::          Other stuff.
@end menu


@node Hiding Headers
@section Hiding Headers
@cindex hiding headers
@cindex deleting headers

The top section of each article is the @dfn{head}.  (The rest is the
@dfn{body}, but you may have guessed that already.)

@vindex gnus-show-all-headers
There is a lot of useful information in the head: the name of the person
who wrote the article, the date it was written and the subject of the
article.  That's well and nice, but there's also lots of information
most people do not want to see---what systems the article has passed
through before reaching you, the @code{Message-ID}, the
@code{References}, etc. ad nauseum---and you'll probably want to get rid
of some of those lines.  If you want to keep all those lines in the
article buffer, you can set @code{gnus-show-all-headers} to @code{t}.

Gnus provides you with two variables for sifting headers:

@table @code

@item gnus-visible-headers
@vindex gnus-visible-headers
If this variable is non-@code{nil}, it should be a regular expression
that says what headers you wish to keep in the article buffer.  All
headers that do not match this variable will be hidden.

For instance, if you only want to see the name of the person who wrote
the article and the subject, you'd say:

@lisp
(setq gnus-visible-headers "^From:\\|^Subject:")
@end lisp

This variable can also be a list of regexps to match headers to
remain visible.

@item gnus-ignored-headers
@vindex gnus-ignored-headers
This variable is the reverse of @code{gnus-visible-headers}.  If this
variable is set (and @code{gnus-visible-headers} is @code{nil}), it
should be a regular expression that matches all lines that you want to
hide.  All lines that do not match this variable will remain visible.

For instance, if you just want to get rid of the @code{References} line
and the @code{Xref} line, you might say:

@lisp
(setq gnus-ignored-headers "^References:\\|^Xref:")
@end lisp

This variable can also be a list of regexps to match headers to
be removed.

Note that if @code{gnus-visible-headers} is non-@code{nil}, this
variable will have no effect.

@end table

@vindex gnus-sorted-header-list
Gnus can also sort the headers for you.  (It does this by default.)  You
can control the sorting by setting the @code{gnus-sorted-header-list}
variable.  It is a list of regular expressions that says in what order
the headers are to be displayed.

For instance, if you want the name of the author of the article first,
and then the subject, you might say something like:

@lisp
(setq gnus-sorted-header-list '("^From:" "^Subject:"))
@end lisp

Any headers that are to remain visible, but are not listed in this
variable, will be displayed in random order after all the headers listed in this variable.

@findex gnus-article-hide-boring-headers
@vindex gnus-boring-article-headers
You can hide further boring headers by setting
@code{gnus-treat-hide-boring-header} to @code{head}.  What this function
does depends on the @code{gnus-boring-article-headers} variable.  It's a
list, but this list doesn't actually contain header names.  Instead is
lists various @dfn{boring conditions} that Gnus can check and remove
from sight.

These conditions are:
@table @code
@item empty
Remove all empty headers.
@item followup-to
Remove the @code{Followup-To} header if it is identical to the
@code{Newsgroups} header.
@item reply-to
Remove the @code{Reply-To} header if it lists the same address as the
@code{From} header.
@item newsgroups
Remove the @code{Newsgroups} header if it only contains the current group
name.
@item date
Remove the @code{Date} header if the article is less than three days
old.
@item long-to
Remove the @code{To} header if it is very long.
@item many-to
Remove all @code{To} headers if there are more than one.
@end table

To include the four three elements, you could say something like;

@lisp
(setq gnus-boring-article-headers
      '(empty followup-to reply-to))
@end lisp

This is also the default value for this variable.


@node Using MIME
@section Using @sc{mime}
@cindex @sc{mime}

Mime is a standard for waving your hands through the air, aimlessly,
while people stand around yawning.

@sc{mime}, however, is a standard for encoding your articles, aimlessly,
while all newsreaders die of fear.

@sc{mime} may specify what character set the article uses, the encoding
of the characters, and it also makes it possible to embed pictures and
other naughty stuff in innocent-looking articles.

@vindex gnus-display-mime-function
@findex gnus-display-mime
Gnus pushes @sc{mime} articles through @code{gnus-display-mime-function}
to display the @sc{mime} parts.  This is @code{gnus-display-mime} by
default, which creates a bundle of clickable buttons that can be used to
display, save and manipulate the @sc{mime} objects.

The following commands are available when you have placed point over a
@sc{mime} button:

@table @kbd
@findex gnus-article-press-button
@item RET (Article)
@itemx BUTTON-2 (Article)
Toggle displaying of the @sc{mime} object
(@code{gnus-article-press-button}).

@findex gnus-mime-view-part
@item M-RET (Article)
@itemx v (Article)
Prompt for a method, and then view the @sc{mime} object using this
method (@code{gnus-mime-view-part}).

@findex gnus-mime-save-part
@item o (Article)
Prompt for a file name, and then save the @sc{mime} object
(@code{gnus-mime-save-part}).

@findex gnus-mime-copy-part
@item c (Article)
Copy the @sc{mime} object to a fresh buffer and display this buffer
(@code{gnus-mime-copy-part}).

@findex gnus-mime-view-part-as-type
@item t (Article)
View the @sc{mime} object as if it were a different @sc{mime} media type
(@code{gnus-mime-view-part-as-type}). 

@findex gnus-mime-pipe-part
@item | (Article)
Output the @sc{mime} object to a process (@code{gnus-mime-pipe-part}).

@findex gnus-mime-inline-part
@item i (Article)
Insert the contents of the @sc{mime} object into the buffer
(@code{gnus-mime-inline-part}) as text/plain.  If given a prefix, insert
the raw contens without decoding.  If given a numerical prefix, you can
do semi-manual charset stuff (see
@code{gnus-summary-show-article-charset-alist} in @pxref{Paging the
Article}).

@findex gnus-mime-action-on-part
@item . (Article)
Interactively run an action on the @sc{mime} object
(@code{gnus-mime-action-on-part}).

@end table

Gnus will display some @sc{mime} objects automatically.  The way Gnus
determines which parts to do this with is described in the Emacs MIME
manual.

It might be best to just use the toggling functions from the article
buffer to avoid getting nasty surprises.  (For instance, you enter the
group @samp{alt.sing-a-long} and, before you know it, @sc{mime} has
decoded the sound file in the article and some horrible sing-a-long song
comes screaming out your speakers, and you can't find the volume button,
because there isn't one, and people are starting to look at you, and you
try to stop the program, but you can't, and you can't find the program
to control the volume, and everybody else in the room suddenly decides
to look at you disdainfully, and you'll feel rather stupid.)

Any similarity to real events and people is purely coincidental.  Ahem.

Also see @pxref{MIME Commands}.


@node Customizing Articles
@section Customizing Articles
@cindex article customization

A slew of functions for customizing how the articles are to look like
exist.  You can call these functions interactively, or you can have them
called automatically when you select the articles.

To have them called automatically, you should set the corresponding
``treatment'' variable.  For instance, to have headers hidden, you'd set
@code{gnus-treat-hide-headers}.  Below is a list of variables that can
be set, but first we discuss the values these variables can have.

Note: Some values, while valid, make little sense.  Check the list below
for sensible values.

@enumerate
@item
@code{nil}: Don't do this treatment.

@item
@code{t}: Do this treatment on all body parts.

@item
@code{head}: Do the treatment on the headers.

@item
@code{last}: Do this treatment on the last part.

@item
An integer: Do this treatment on all body parts that have a length less
than this number.

@item
A list of strings: Do this treatment on all body parts that are in
articles that are read in groups that have names that match one of the
regexps in the list.

@item
A list where the first element is not a string:

The list is evaluated recursively.  The first element of the list is a
predicate.  The following predicates are recognized: @code{or},
@code{and}, @code{not} and @code{typep}.  Here's an example:

@lisp
(or last
    (typep "text/x-vcard"))
@end lisp

@end enumerate

You may have noticed that the word @dfn{part} is used here.  This refers
to the fact that some messages are @sc{mime} multipart articles that may
be divided into several parts.  Articles that are not multiparts are
considered to contain just a single part.

@vindex gnus-article-treat-types
Are the treatments applied to all sorts of multipart parts?  Yes, if you
want to, but by default, only @samp{text/plain} parts are given the
treatment.  This is controlled by the @code{gnus-article-treat-types}
variable, which is a list of regular expressions that are matched to the
type of the part.  This variable is ignored if the value of the
controlling variable is a predicate list, as described above.

The following treatment options are available.  The easiest way to
customize this is to examine the @code{gnus-article-treat} customization
group.  Values in parenthesis are suggested sensible values.  Others are
possible but those listed are probably sufficient for most people.

@table @code
@item gnus-treat-highlight-signature (t, last)
@item gnus-treat-buttonize (t, integer)
@item gnus-treat-buttonize-head (head)
@item gnus-treat-emphasize (t, head, integer)
@item gnus-treat-fill-article (t, integer)
@item gnus-treat-strip-cr (t, integer)
@item gnus-treat-hide-headers (head)
@item gnus-treat-hide-boring-headers (head)
@item gnus-treat-hide-signature (t, last)
@item gnus-treat-hide-citation (t, integer)
@item gnus-treat-hide-citation-maybe (t, integer)
@item gnus-treat-strip-pgp (t, last, integer)
@item gnus-treat-strip-pem (t, last, integer)
@item gnus-treat-highlight-headers (head)
@item gnus-treat-highlight-citation (t, integer)
@item gnus-treat-highlight-signature (t, last, integer)
@item gnus-treat-date-ut (head)
@item gnus-treat-date-local (head)
@item gnus-treat-date-lapsed (head)
@item gnus-treat-date-original (head)
@item gnus-treat-date-iso8601 (head)
@item gnus-treat-date-user-defined (head)
@item gnus-treat-strip-headers-in-body (t, integer)
@item gnus-treat-strip-trailing-blank-lines (t, last, integer)
@item gnus-treat-strip-leading-blank-lines (t, integer)
@item gnus-treat-strip-multiple-blank-lines (t, integer)
@item gnus-treat-overstrike (t, integer)
@item gnus-treat-display-xface (head)
@item gnus-treat-display-smileys (t, integer)
@item gnus-treat-display-picons (head)
@item gnus-treat-capitalize-sentences (t, integer)
@item gnus-treat-fill-long-lines (t, integer)
@item gnus-treat-play-sounds
@item gnus-treat-translate
@end table

@vindex gnus-part-display-hook
You can, of course, write your own functions to be called from
@code{gnus-part-display-hook}.  The functions are called narrowed to the
part, and you can do anything you like, pretty much.  There is no
information that you have to keep in the buffer---you can change
everything.  


@node Article Keymap
@section Article Keymap

Most of the keystrokes in the summary buffer can also be used in the
article buffer.  They should behave as if you typed them in the summary
buffer, which means that you don't actually have to have a summary
buffer displayed while reading.  You can do it all from the article
buffer.

A few additional keystrokes are available:

@table @kbd

@item SPACE
@kindex SPACE (Article)
@findex gnus-article-next-page
Scroll forwards one page (@code{gnus-article-next-page}).

@item DEL
@kindex DEL (Article)
@findex gnus-article-prev-page
Scroll backwards one page (@code{gnus-article-prev-page}).

@item C-c ^
@kindex C-c ^ (Article)
@findex gnus-article-refer-article
If point is in the neighborhood of a @code{Message-ID} and you press
@kbd{C-c ^}, Gnus will try to get that article from the server
(@code{gnus-article-refer-article}).

@item C-c C-m
@kindex C-c C-m (Article)
@findex gnus-article-mail
Send a reply to the address near point (@code{gnus-article-mail}).  If
given a prefix, include the mail.

@item s
@kindex s (Article)
@findex gnus-article-show-summary
Reconfigure the buffers so that the summary buffer becomes visible
(@code{gnus-article-show-summary}).

@item ?
@kindex ? (Article)
@findex gnus-article-describe-briefly
Give a very brief description of the available keystrokes
(@code{gnus-article-describe-briefly}).

@item TAB
@kindex TAB (Article)
@findex gnus-article-next-button
Go to the next button, if any (@code{gnus-article-next-button}).  This
only makes sense if you have buttonizing turned on.

@item M-TAB
@kindex M-TAB (Article)
@findex gnus-article-prev-button
Go to the previous button, if any (@code{gnus-article-prev-button}).

@end table


@node Misc Article
@section Misc Article

@table @code

@item gnus-single-article-buffer
@vindex gnus-single-article-buffer
If non-@code{nil}, use the same article buffer for all the groups.
(This is the default.)  If @code{nil}, each group will have its own
article buffer.

@vindex gnus-article-decode-hook
@item gnus-article-decode-hook
@cindex MIME
Hook used to decode @sc{mime} articles.  The default value is
@code{(article-decode-charset article-decode-encoded-words)}

@vindex gnus-article-prepare-hook
@item gnus-article-prepare-hook
This hook is called right after the article has been inserted into the
article buffer.  It is mainly intended for functions that do something
depending on the contents; it should probably not be used for changing
the contents of the article buffer.

@item gnus-article-mode-hook
@vindex gnus-article-mode-hook
Hook called in article mode buffers.

@item gnus-article-mode-syntax-table
@vindex gnus-article-mode-syntax-table
Syntax table used in article buffers.  It is initialized from
@code{text-mode-syntax-table}.

@vindex gnus-article-mode-line-format
@item gnus-article-mode-line-format
This variable is a format string along the same lines as
@code{gnus-summary-mode-line-format} (@pxref{Mode Line Formatting}).  It
accepts the same format specifications as that variable, with two
extensions:

@table @samp
@item w
The @dfn{wash status} of the article.  This is a short string with one
character for each possible article wash operation that may have been
performed.
@item m
The number of @sc{mime} parts in the article.
@end table

@vindex gnus-break-pages

@item gnus-break-pages
Controls whether @dfn{page breaking} is to take place.  If this variable
is non-@code{nil}, the articles will be divided into pages whenever a
page delimiter appears in the article.  If this variable is @code{nil},
paging will not be done.

@item gnus-page-delimiter
@vindex gnus-page-delimiter
This is the delimiter mentioned above.  By default, it is @samp{^L}
(formfeed).
@end table


@node Composing Messages
@chapter Composing Messages
@cindex composing messages
@cindex messages
@cindex mail
@cindex sending mail
@cindex reply
@cindex followup
@cindex post
@cindex using gpg

@kindex C-c C-c (Post)
All commands for posting and mailing will put you in a message buffer
where you can edit the article all you like, before you send the
article by pressing @kbd{C-c C-c}.  @xref{Top, , Top, message, The
Message Manual}.  Where the message will be posted/mailed to depends
on your setup (@pxref{Posting Server}).

@menu
* Mail::                 Mailing and replying.
* Post::                 Posting and following up.
* Posting Server::       What server should you post via?
* Mail and Post::        Mailing and posting at the same time.
* Archived Messages::    Where Gnus stores the messages you've sent.
* Posting Styles::       An easier way to specify who you are.
* Drafts::               Postponing messages and rejected messages.
* Rejected Articles::    What happens if the server doesn't like your article?
* Using GPG::            How to use GPG and MML to sign and encrypt messages
@end menu

Also see @pxref{Canceling and Superseding} for information on how to
remove articles you shouldn't have posted.


@node Mail
@section Mail

Variables for customizing outgoing mail:

@table @code
@item gnus-uu-digest-headers
@vindex gnus-uu-digest-headers
List of regexps to match headers included in digested messages.  The
headers will be included in the sequence they are matched.

@item gnus-add-to-list
@vindex gnus-add-to-list
If non-@code{nil}, add a @code{to-list} group parameter to mail groups
that have none when you do a @kbd{a}.

@item message-send-mail-partially-limit
@vindex message-send-mail-partially-limit
The limitation of messages sent as message/partial.
The lower bound of message size in characters, beyond which the message 
should be sent in several parts. If it is nil, the size is unlimited.

@end table


@node Post
@section Post

Variables for composing news articles:

@table @code
@item gnus-sent-message-ids-file
@vindex gnus-sent-message-ids-file
Gnus will keep a @code{Message-ID} history file of all the mails it has
sent.  If it discovers that it has already sent a mail, it will ask the
user whether to re-send the mail.  (This is primarily useful when
dealing with @sc{soup} packets and the like where one is apt to send the
same packet multiple times.)  This variable says what the name of this
history file is.  It is @file{~/News/Sent-Message-IDs} by default.  Set
this variable to @code{nil} if you don't want Gnus to keep a history
file.

@item gnus-sent-message-ids-length
@vindex gnus-sent-message-ids-length
This variable says how many @code{Message-ID}s to keep in the history
file.  It is 1000 by default.

@end table


@node Posting Server
@section Posting Server

When you press those magical @kbd{C-c C-c} keys to ship off your latest
(extremely intelligent, of course) article, where does it go?

Thank you for asking.  I hate you.

@vindex gnus-post-method

It can be quite complicated.  Normally, Gnus will use the same native
server.  However.  If your native server doesn't allow posting, just
reading, you probably want to use some other server to post your
(extremely intelligent and fabulously interesting) articles.  You can
then set the @code{gnus-post-method} to some other method:

@lisp
(setq gnus-post-method '(nnspool ""))
@end lisp

Now, if you've done this, and then this server rejects your article, or
this server is down, what do you do then?  To override this variable you
can use a non-zero prefix to the @kbd{C-c C-c} command to force using
the ``current'' server for posting.

If you give a zero prefix (i.e., @kbd{C-u 0 C-c C-c}) to that command,
Gnus will prompt you for what method to use for posting.

You can also set @code{gnus-post-method} to a list of select methods.
If that's the case, Gnus will always prompt you for what method to use
for posting.

Finally, if you want to always post using the same select method as
you're reading from (which might be convenient if you're reading lots of
groups from different private servers), you can set this variable to
@code{current}.


@node Mail and Post
@section Mail and Post

Here's a list of variables relevant to both mailing and
posting:

@table @code
@item gnus-mailing-list-groups
@findex gnus-mailing-list-groups
@cindex mailing lists

If your news server offers groups that are really mailing lists
gatewayed to the @sc{nntp} server, you can read those groups without
problems, but you can't post/followup to them without some difficulty.
One solution is to add a @code{to-address} to the group parameters
(@pxref{Group Parameters}).  An easier thing to do is set the
@code{gnus-mailing-list-groups} to a regexp that matches the groups that
really are mailing lists.  Then, at least, followups to the mailing
lists will work most of the time.  Posting to these groups (@kbd{a}) is
still a pain, though.

@end table

You may want to do spell-checking on messages that you send out.  Or, if
you don't want to spell-check by hand, you could add automatic
spell-checking via the @code{ispell} package:

@cindex ispell
@findex ispell-message
@lisp
(add-hook 'message-send-hook 'ispell-message)
@end lisp

If you want to change the @code{ispell} dictionary based on what group
you're in, you could say something like the following:

@lisp
(add-hook 'gnus-select-group-hook
          (lambda ()
            (cond
             ((string-match "^de\\." gnus-newsgroup-name)
              (ispell-change-dictionary "deutsch"))
             (t
              (ispell-change-dictionary "english")))))
@end lisp

Modify to suit your needs.


@node Archived Messages
@section Archived Messages
@cindex archived messages
@cindex sent messages

Gnus provides a few different methods for storing the mail and news you
send.  The default method is to use the @dfn{archive virtual server} to
store the messages.  If you want to disable this completely, the
@code{gnus-message-archive-group} variable should be @code{nil}, which
is the default.

@vindex gnus-message-archive-method
@code{gnus-message-archive-method} says what virtual server Gnus is to
use to store sent messages.  The default is:

@lisp
(nnfolder "archive"
          (nnfolder-directory   "~/Mail/archive")
          (nnfolder-active-file "~/Mail/archive/active")
          (nnfolder-get-new-mail nil)
          (nnfolder-inhibit-expiry t))
@end lisp

You can, however, use any mail select method (@code{nnml},
@code{nnmbox}, etc.).  @code{nnfolder} is a quite likeable select method
for doing this sort of thing, though.  If you don't like the default
directory chosen, you could say something like:

@lisp
(setq gnus-message-archive-method
      '(nnfolder "archive"
                 (nnfolder-inhibit-expiry t)
                 (nnfolder-active-file "~/News/sent-mail/active")
                 (nnfolder-directory "~/News/sent-mail/")))
@end lisp

@vindex gnus-message-archive-group
@cindex Gcc
Gnus will insert @code{Gcc} headers in all outgoing messages that point
to one or more group(s) on that server.  Which group to use is
determined by the @code{gnus-message-archive-group} variable.

This variable can be used to do the following:

@itemize @bullet
@item a string
Messages will be saved in that group.

Note that you can include a select method in the group name, then the
message will not be stored in the select method given by
@code{gnus-message-archive-method}, but in the select method specified
by the group name, instead.  Suppose @code{gnus-message-archive-method}
has the default value shown above.  Then setting
@code{gnus-message-archive-group} to @code{"foo"} means that outgoing
messages are stored in @samp{nnfolder+archive:foo}, but if you use the
value @code{"nnml:foo"}, then outgoing messages will be stored in
@samp{nnml:foo}.
@item a list of strings
Messages will be saved in all those groups.
@item an alist of regexps, functions and forms
When a key ``matches'', the result is used.
@item @code{nil}
No message archiving will take place.  This is the default.
@end itemize

Let's illustrate:

Just saving to a single group called @samp{MisK}:
@lisp
(setq gnus-message-archive-group "MisK")
@end lisp

Saving to two groups, @samp{MisK} and @samp{safe}:
@lisp
(setq gnus-message-archive-group '("MisK" "safe"))
@end lisp

Save to different groups based on what group you are in:
@lisp
(setq gnus-message-archive-group
      '(("^alt" "sent-to-alt")
        ("mail" "sent-to-mail")
        (".*" "sent-to-misc")))
@end lisp

More complex stuff:
@lisp
(setq gnus-message-archive-group
      '((if (message-news-p)
            "misc-news"
          "misc-mail")))
@end lisp

How about storing all news messages in one file, but storing all mail
messages in one file per month:

@lisp
(setq gnus-message-archive-group
      '((if (message-news-p)
            "misc-news"
          (concat "mail." (format-time-string "%Y-%m")))))
@end lisp

(XEmacs 19.13 doesn't have @code{format-time-string}, so you'll have to
use a different value for @code{gnus-message-archive-group} there.)

Now, when you send a message off, it will be stored in the appropriate
group.  (If you want to disable storing for just one particular message,
you can just remove the @code{Gcc} header that has been inserted.)  The
archive group will appear in the group buffer the next time you start
Gnus, or the next time you press @kbd{F} in the group buffer.  You can
enter it and read the articles in it just like you'd read any other
group.  If the group gets really big and annoying, you can simply rename
if (using @kbd{G r} in the group buffer) to something
nice---@samp{misc-mail-september-1995}, or whatever.  New messages will
continue to be stored in the old (now empty) group.

That's the default method of archiving sent messages.  Gnus offers a
different way for the people who don't like the default method.  In that
case you should set @code{gnus-message-archive-group} to @code{nil};
this will disable archiving.

@table @code
@item gnus-outgoing-message-group
@vindex gnus-outgoing-message-group
All outgoing messages will be put in this group.  If you want to store
all your outgoing mail and articles in the group @samp{nnml:archive},
you set this variable to that value.  This variable can also be a list of
group names.

If you want to have greater control over what group to put each
message in, you can set this variable to a function that checks the
current newsgroup name and then returns a suitable group name (or list
of names).

This variable can be used instead of @code{gnus-message-archive-group},
but the latter is the preferred method.

@item gnus-inews-mark-gcc-as-read
@vindex gnus-inews-mark-gcc-as-read
If non-@code{nil}, automatically mark @code{Gcc} articles as read.

@end table


@node Posting Styles
@section Posting Styles
@cindex posting styles
@cindex styles

All them variables, they make my head swim.

So what if you want a different @code{Organization} and signature based
on what groups you post to?  And you post both from your home machine
and your work machine, and you want different @code{From} lines, and so
on?

@vindex gnus-posting-styles
One way to do stuff like that is to write clever hooks that change the
variables you need to have changed.  That's a bit boring, so somebody
came up with the bright idea of letting the user specify these things in
a handy alist.  Here's an example of a @code{gnus-posting-styles}
variable:

@lisp
((".*"
  (signature "Peace and happiness")
  (organization "What me?"))
 ("^comp"
  (signature "Death to everybody"))
 ("comp.emacs.i-love-it"
  (organization "Emacs is it")))
@end lisp

As you might surmise from this example, this alist consists of several
@dfn{styles}.  Each style will be applicable if the first element
``matches'', in some form or other.  The entire alist will be iterated
over, from the beginning towards the end, and each match will be
applied, which means that attributes in later styles that match override
the same attributes in earlier matching styles.  So
@samp{comp.programming.literate} will have the @samp{Death to everybody}
signature and the @samp{What me?} @code{Organization} header.

The first element in each style is called the @code{match}.  If it's a
string, then Gnus will try to regexp match it against the group name.
If it is the symbol @code{header}, then Gnus will look for header that
match the next element in the match, and compare that to the last header
in the match.  If it's a function symbol, that function will be called
with no arguments.  If it's a variable symbol, then the variable will be
referenced.  If it's a list, then that list will be @code{eval}ed.  In
any case, if this returns a non-@code{nil} value, then the style is said
to @dfn{match}.

Each style may contain a arbitrary amount of @dfn{attributes}.  Each
attribute consists of a @code{(@var{name} . @var{value})} pair.  The
attribute name can be one of @code{signature}, @code{signature-file},
@code{organization}, @code{address}, @code{name} or @code{body}.  The
attribute name can also be a string.  In that case, this will be used as
a header name, and the value will be inserted in the headers of the
article; if the value is @code{nil}, the header name will be removed.
If the attribute name is @code{eval}, the form is evaluated, and the
result is thrown away.

The attribute value can be a string (used verbatim), a function with
zero arguments (the return value will be used), a variable (its value
will be used) or a list (it will be @code{eval}ed and the return value
will be used).  The functions and sexps are called/@code{eval}ed in the
message buffer that is being set up.  The headers of the current article
are available through the @code{message-reply-headers} variable.

If you wish to check whether the message you are about to compose is
meant to be a news article or a mail message, you can check the values
of the @code{message-news-p} and @code{message-mail-p} functions.

@findex message-mail-p
@findex message-news-p

So here's a new example:

@lisp
(setq gnus-posting-styles
      '((".*"
         (signature-file "~/.signature")
         (name "User Name")
         ("X-Home-Page" (getenv "WWW_HOME"))
         (organization "People's Front Against MWM"))
        ("^rec.humor"
         (signature my-funny-signature-randomizer))
        ((equal (system-name) "gnarly")
         (signature my-quote-randomizer))
        ((message-news-p)
         (signature my-news-signature))
        (header "From\\|To" "larsi.*org"
                (Organization "Somewhere, Inc."))
        ((posting-from-work-p)
         (signature-file "~/.work-signature")
         (address "user@@bar.foo")
         (body "You are fired.\n\nSincerely, your boss.")
         (organization "Important Work, Inc"))
        ("nnml:.*"
         (From (save-excursion
                 (set-buffer gnus-article-buffer)
                 (message-fetch-field "to"))))
        ("^nn.+:"
         (signature-file "~/.mail-signature"))))
@end lisp

The @samp{nnml:.*} rule means that you use the @code{To} address as the
@code{From} address in all your outgoing replies, which might be handy
if you fill many roles.


@node Drafts
@section Drafts
@cindex drafts

If you are writing a message (mail or news) and suddenly remember that
you have a steak in the oven (or some pesto in the food processor, you
craaazy vegetarians), you'll probably wish there was a method to save
the message you are writing so that you can continue editing it some
other day, and send it when you feel its finished.

Well, don't worry about it.  Whenever you start composing a message of
some sort using the Gnus mail and post commands, the buffer you get will
automatically associate to an article in a special @dfn{draft} group.
If you save the buffer the normal way (@kbd{C-x C-s}, for instance), the
article will be saved there.  (Auto-save files also go to the draft
group.)

@cindex nndraft
@vindex nndraft-directory
The draft group is a special group (which is implemented as an
@code{nndraft} group, if you absolutely have to know) called
@samp{nndraft:drafts}.  The variable @code{nndraft-directory} says where
@code{nndraft} is to store its files.  What makes this group special is
that you can't tick any articles in it or mark any articles as
read---all articles in the group are permanently unread.

If the group doesn't exist, it will be created and you'll be subscribed
to it.  The only way to make it disappear from the Group buffer is to
unsubscribe it.

@c @findex gnus-dissociate-buffer-from-draft
@c @kindex C-c M-d (Mail)
@c @kindex C-c M-d (Post)
@c @findex gnus-associate-buffer-with-draft
@c @kindex C-c C-d (Mail)
@c @kindex C-c C-d (Post)
@c If you're writing some super-secret message that you later want to
@c encode with PGP before sending, you may wish to turn the auto-saving
@c (and association with the draft group) off.  You never know who might be
@c interested in reading all your extremely valuable and terribly horrible
@c and interesting secrets.  The @kbd{C-c M-d}
@c (@code{gnus-dissociate-buffer-from-draft}) command does that for you.
@c If you change your mind and want to turn the auto-saving back on again,
@c @kbd{C-c C-d} (@code{gnus-associate-buffer-with-draft} does that.
@c
@c @vindex gnus-use-draft
@c To leave association with the draft group off by default, set
@c @code{gnus-use-draft} to @code{nil}.  It is @code{t} by default.

@findex gnus-draft-edit-message
@kindex D e (Draft)
When you want to continue editing the article, you simply enter the
draft group and push @kbd{D e} (@code{gnus-draft-edit-message}) to do
that.  You will be placed in a buffer where you left off.

Rejected articles will also be put in this draft group (@pxref{Rejected
Articles}).

@findex gnus-draft-send-all-messages
@findex gnus-draft-send-message
If you have lots of rejected messages you want to post (or mail) without
doing further editing, you can use the @kbd{D s} command
(@code{gnus-draft-send-message}).  This command understands the
process/prefix convention (@pxref{Process/Prefix}).  The @kbd{D S}
command (@code{gnus-draft-send-all-messages}) will ship off all messages
in the buffer.

If you have some messages that you wish not to send, you can use the
@kbd{D t} (@code{gnus-draft-toggle-sending}) command to mark the message
as unsendable.  This is a toggling command.


@node Rejected Articles
@section Rejected Articles
@cindex rejected articles

Sometimes a news server will reject an article.  Perhaps the server
doesn't like your face.  Perhaps it just feels miserable.  Perhaps
@emph{there be demons}.  Perhaps you have included too much cited text.
Perhaps the disk is full.  Perhaps the server is down.

These situations are, of course, totally beyond the control of Gnus.
(Gnus, of course, loves the way you look, always feels great, has angels
fluttering around inside of it, doesn't care about how much cited text
you include, never runs full and never goes down.)  So Gnus saves these
articles until some later time when the server feels better.

The rejected articles will automatically be put in a special draft group
(@pxref{Drafts}).  When the server comes back up again, you'd then
typically enter that group and send all the articles off.

@node Using GPG
@section Using GPG
@cindex using gpg

Gnus has an ALPHA support to GPG that's provided by @file{gpg.el} and
@file{mml2015.el}. When viewing signed or encrypted messages, Gnus automatically
asks if you want to verify or decrypt them. 

To use this correctly with GPG, you'll need the following lisp code in your
@file{~/.emacs} or @file{~/.gnus}:

@lisp
(setq mml2015-use 'gpg)
(setq gpg-temp-directory "~/.gnupg/tmp")
@end lisp

The @code{gpg-temp-directory} need to point to a directory with permissions set
to 700, for your own safety.

If you want to benefit of PGP2.6 compatibility, you might create a script named
@file{gpg-2comp} with these instructions:

@code{
#!/bin/sh
exec gpg --rfc1991 "$@@"
}

If you don't want to use such compatibility, you can add the following line to
your @file{~/.emacs} or @file{~/.gnus}:

@lisp
(setq gpg-command-default-alist (quote ((gpg . "gpg") (gpg-2comp . "gpg"))))
@end lisp

To sign or encrypt your message you may choose to use the MML Security menu or
@kbd{M-m s p} to sign your message using PGP/MIME, @kbd{M-m s s} to sign your
message using S/MIME. There's also @kbd{M-m c p} to encrypt your message with
PGP/MIME and @kbd{M-m c s} to encrypt using S/MIME.

Gnus will ask for your passphrase three times and then it will send your
message, if you've typed it correctly.


@node Select Methods
@chapter Select Methods
@cindex foreign groups
@cindex select methods

A @dfn{foreign group} is a group not read by the usual (or
default) means.  It could be, for instance, a group from a different
@sc{nntp} server, it could be a virtual group, or it could be your own
personal mail group.

A foreign group (or any group, really) is specified by a @dfn{name} and
a @dfn{select method}.  To take the latter first, a select method is a
list where the first element says what backend to use (e.g. @code{nntp},
@code{nnspool}, @code{nnml}) and the second element is the @dfn{server
name}.  There may be additional elements in the select method, where the
value may have special meaning for the backend in question.

One could say that a select method defines a @dfn{virtual server}---so
we do just that (@pxref{The Server Buffer}).

The @dfn{name} of the group is the name the backend will recognize the
group as.

For instance, the group @samp{soc.motss} on the @sc{nntp} server
@samp{some.where.edu} will have the name @samp{soc.motss} and select
method @code{(nntp "some.where.edu")}.  Gnus will call this group
@samp{nntp+some.where.edu:soc.motss}, even though the @code{nntp}
backend just knows this group as @samp{soc.motss}.

The different methods all have their peculiarities, of course.

@menu
* The Server Buffer::     Making and editing virtual servers.
* Getting News::          Reading USENET news with Gnus.
* Getting Mail::          Reading your personal mail with Gnus.
* Browsing the Web::      Getting messages from a plethora of Web sources.
* Other Sources::         Reading directories, files, SOUP packets.
* Combined Groups::       Combining groups into one group.
* Gnus Unplugged::        Reading news and mail offline.
@end menu


@node The Server Buffer
@section The Server Buffer

Traditionally, a @dfn{server} is a machine or a piece of software that
one connects to, and then requests information from.  Gnus does not
connect directly to any real servers, but does all transactions through
one backend or other.  But that's just putting one layer more between
the actual media and Gnus, so we might just as well say that each
backend represents a virtual server.

For instance, the @code{nntp} backend may be used to connect to several
different actual @sc{nntp} servers, or, perhaps, to many different ports
on the same actual @sc{nntp} server.  You tell Gnus which backend to
use, and what parameters to set by specifying a @dfn{select method}.

These select method specifications can sometimes become quite
complicated---say, for instance, that you want to read from the
@sc{nntp} server @samp{news.funet.fi} on port number 13, which
hangs if queried for @sc{nov} headers and has a buggy select.  Ahem.
Anyways, if you had to specify that for each group that used this
server, that would be too much work, so Gnus offers a way of naming
select methods, which is what you do in the server buffer.

To enter the server buffer, use the @kbd{^}
(@code{gnus-group-enter-server-mode}) command in the group buffer.

@menu
* Server Buffer Format::      You can customize the look of this buffer.
* Server Commands::           Commands to manipulate servers.
* Example Methods::           Examples server specifications.
* Creating a Virtual Server:: An example session.
* Server Variables::          Which variables to set.
* Servers and Methods::       You can use server names as select methods.
* Unavailable Servers::       Some servers you try to contact may be down.
@end menu

@vindex gnus-server-mode-hook
@code{gnus-server-mode-hook} is run when creating the server buffer.


@node Server Buffer Format
@subsection Server Buffer Format
@cindex server buffer format

@vindex gnus-server-line-format
You can change the look of the server buffer lines by changing the
@code{gnus-server-line-format} variable.  This is a @code{format}-like
variable, with some simple extensions:

@table @samp

@item h
How the news is fetched---the backend name.

@item n
The name of this server.

@item w
Where the news is to be fetched from---the address.

@item s
The opened/closed/denied status of the server.
@end table

@vindex gnus-server-mode-line-format
The mode line can also be customized by using the
@code{gnus-server-mode-line-format} variable (@pxref{Mode Line
Formatting}).  The following specs are understood:

@table @samp
@item S
Server name.

@item M
Server method.
@end table

Also @pxref{Formatting Variables}.


@node Server Commands
@subsection Server Commands
@cindex server commands

@table @kbd

@item a
@kindex a (Server)
@findex gnus-server-add-server
Add a new server (@code{gnus-server-add-server}).

@item e
@kindex e (Server)
@findex gnus-server-edit-server
Edit a server (@code{gnus-server-edit-server}).

@item SPACE
@kindex SPACE (Server)
@findex gnus-server-read-server
Browse the current server (@code{gnus-server-read-server}).

@item q
@kindex q (Server)
@findex gnus-server-exit
Return to the group buffer (@code{gnus-server-exit}).

@item k
@kindex k (Server)
@findex gnus-server-kill-server
Kill the current server (@code{gnus-server-kill-server}).

@item y
@kindex y (Server)
@findex gnus-server-yank-server
Yank the previously killed server (@code{gnus-server-yank-server}).

@item c
@kindex c (Server)
@findex gnus-server-copy-server
Copy the current server (@code{gnus-server-copy-server}).

@item l
@kindex l (Server)
@findex gnus-server-list-servers
List all servers (@code{gnus-server-list-servers}).

@item s
@kindex s (Server)
@findex gnus-server-scan-server
Request that the server scan its sources for new articles
(@code{gnus-server-scan-server}).  This is mainly sensible with mail
servers.

@item g
@kindex g (Server)
@findex gnus-server-regenerate-server
Request that the server regenerate all its data structures
(@code{gnus-server-regenerate-server}).  This can be useful if you have
a mail backend that has gotten out of synch.

@end table


@node Example Methods
@subsection Example Methods

Most select methods are pretty simple and self-explanatory:

@lisp
(nntp "news.funet.fi")
@end lisp

Reading directly from the spool is even simpler:

@lisp
(nnspool "")
@end lisp

As you can see, the first element in a select method is the name of the
backend, and the second is the @dfn{address}, or @dfn{name}, if you
will.

After these two elements, there may be an arbitrary number of
@code{(@var{variable} @var{form})} pairs.

To go back to the first example---imagine that you want to read from
port 15 on that machine.  This is what the select method should
look like then:

@lisp
(nntp "news.funet.fi" (nntp-port-number 15))
@end lisp

You should read the documentation to each backend to find out what
variables are relevant, but here's an @code{nnmh} example:

@code{nnmh} is a mail backend that reads a spool-like structure.  Say
you have two structures that you wish to access: One is your private
mail spool, and the other is a public one.  Here's the possible spec for
your private mail:

@lisp
(nnmh "private" (nnmh-directory "~/private/mail/"))
@end lisp

(This server is then called @samp{private}, but you may have guessed
that.)

Here's the method for a public spool:

@lisp
(nnmh "public"
      (nnmh-directory "/usr/information/spool/")
      (nnmh-get-new-mail nil))
@end lisp

@cindex proxy
@cindex firewall

If you are behind a firewall and only have access to the @sc{nntp}
server from the firewall machine, you can instruct Gnus to @code{rlogin}
on the firewall machine and telnet from there to the @sc{nntp} server.
Doing this can be rather fiddly, but your virtual server definition
should probably look something like this:

@lisp
(nntp "firewall"
      (nntp-address "the.firewall.machine")
      (nntp-open-connection-function nntp-open-rlogin)
      (nntp-end-of-line "\n")
      (nntp-rlogin-parameters
       ("telnet" "the.real.nntp.host" "nntp")))
@end lisp

If you want to use the wonderful @code{ssh} program to provide a
compressed connection over the modem line, you could create a virtual
server that would look something like this:

@lisp
(nntp "news"
       (nntp-address "copper.uio.no")
       (nntp-rlogin-program "ssh")
       (nntp-open-connection-function nntp-open-rlogin)
       (nntp-end-of-line "\n")
       (nntp-rlogin-parameters
        ("telnet" "news.uio.no" "nntp")))
@end lisp

This means that you have to have set up @code{ssh-agent} correctly to
provide automatic authorization, of course.  And to get a compressed
connection, you have to have the @samp{Compression} option in the
@code{ssh} @file{config} file.


@node Creating a Virtual Server
@subsection Creating a Virtual Server

If you're saving lots of articles in the cache by using persistent
articles, you may want to create a virtual server to read the cache.

First you need to add a new server.  The @kbd{a} command does that.  It
would probably be best to use @code{nnspool} to read the cache.  You
could also use @code{nnml} or @code{nnmh}, though.

Type @kbd{a nnspool RET cache RET}.

You should now have a brand new @code{nnspool} virtual server called
@samp{cache}.  You now need to edit it to have the right definitions.
Type @kbd{e} to edit the server.  You'll be entered into a buffer that
will contain the following:

@lisp
(nnspool "cache")
@end lisp

Change that to:

@lisp
(nnspool "cache"
         (nnspool-spool-directory "~/News/cache/")
         (nnspool-nov-directory "~/News/cache/")
         (nnspool-active-file "~/News/cache/active"))
@end lisp

Type @kbd{C-c C-c} to return to the server buffer.  If you now press
@kbd{RET} over this virtual server, you should be entered into a browse
buffer, and you should be able to enter any of the groups displayed.


@node Server Variables
@subsection Server Variables

One sticky point when defining variables (both on backends and in Emacs
in general) is that some variables are typically initialized from other
variables when the definition of the variables is being loaded.  If you
change the "base" variable after the variables have been loaded, you
won't change the "derived" variables.

This typically affects directory and file variables.  For instance,
@code{nnml-directory} is @file{~/Mail/} by default, and all @code{nnml}
directory variables are initialized from that variable, so
@code{nnml-active-file} will be @file{~/Mail/active}.  If you define a
new virtual @code{nnml} server, it will @emph{not} suffice to set just
@code{nnml-directory}---you have to explicitly set all the file
variables to be what you want them to be.  For a complete list of
variables for each backend, see each backend's section later in this
manual, but here's an example @code{nnml} definition:

@lisp
(nnml "public"
      (nnml-directory "~/my-mail/")
      (nnml-active-file "~/my-mail/active")
      (nnml-newsgroups-file "~/my-mail/newsgroups"))
@end lisp


@node Servers and Methods
@subsection Servers and Methods

Wherever you would normally use a select method
(e.g. @code{gnus-secondary-select-method}, in the group select method,
when browsing a foreign server) you can use a virtual server name
instead.  This could potentially save lots of typing.  And it's nice all
over.


@node Unavailable Servers
@subsection Unavailable Servers

If a server seems to be unreachable, Gnus will mark that server as
@code{denied}.  That means that any subsequent attempt to make contact
with that server will just be ignored.  ``It can't be opened,'' Gnus
will tell you, without making the least effort to see whether that is
actually the case or not.

That might seem quite naughty, but it does make sense most of the time.
Let's say you have 10 groups subscribed to on server
@samp{nephelococcygia.com}.  This server is located somewhere quite far
away from you and the machine is quite slow, so it takes 1 minute just
to find out that it refuses connection to you today.  If Gnus were to
attempt to do that 10 times, you'd be quite annoyed, so Gnus won't
attempt to do that.  Once it has gotten a single ``connection refused'',
it will regard that server as ``down''.

So, what happens if the machine was only feeling unwell temporarily?
How do you test to see whether the machine has come up again?

You jump to the server buffer (@pxref{The Server Buffer}) and poke it
with the following commands:

@table @kbd

@item O
@kindex O (Server)
@findex gnus-server-open-server
Try to establish connection to the server on the current line
(@code{gnus-server-open-server}).

@item C
@kindex C (Server)
@findex gnus-server-close-server
Close the connection (if any) to the server
(@code{gnus-server-close-server}).

@item D
@kindex D (Server)
@findex gnus-server-deny-server
Mark the current server as unreachable
(@code{gnus-server-deny-server}).

@item M-o
@kindex M-o (Server)
@findex gnus-server-open-all-servers
Open the connections to all servers in the buffer
(@code{gnus-server-open-all-servers}).

@item M-c
@kindex M-c (Server)
@findex gnus-server-close-all-servers
Close the connections to all servers in the buffer
(@code{gnus-server-close-all-servers}).

@item R
@kindex R (Server)
@findex gnus-server-remove-denials
Remove all marks to whether Gnus was denied connection from any servers
(@code{gnus-server-remove-denials}).

@end table


@node Getting News
@section Getting News
@cindex reading news
@cindex news backends

A newsreader is normally used for reading news.  Gnus currently provides
only two methods of getting news---it can read from an @sc{nntp} server,
or it can read from a local spool.

@menu
* NNTP::               Reading news from an @sc{nntp} server.
* News Spool::         Reading news from the local spool.
@end menu


@node NNTP
@subsection @sc{nntp}
@cindex nntp

Subscribing to a foreign group from an @sc{nntp} server is rather easy.
You just specify @code{nntp} as method and the address of the @sc{nntp}
server as the, uhm, address.

If the @sc{nntp} server is located at a non-standard port, setting the
third element of the select method to this port number should allow you
to connect to the right port.  You'll have to edit the group info for
that (@pxref{Foreign Groups}).

The name of the foreign group can be the same as a native group.  In
fact, you can subscribe to the same group from as many different servers
you feel like.  There will be no name collisions.

The following variables can be used to create a virtual @code{nntp}
server:

@table @code

@item nntp-server-opened-hook
@vindex nntp-server-opened-hook
@cindex @sc{mode reader}
@cindex authinfo
@cindex authentification
@cindex nntp authentification
@findex nntp-send-authinfo
@findex nntp-send-mode-reader
is run after a connection has been made.  It can be used to send
commands to the @sc{nntp} server after it has been contacted.  By
default it sends the command @code{MODE READER} to the server with the
@code{nntp-send-mode-reader} function.  This function should always be
present in this hook.

@item nntp-authinfo-function
@vindex nntp-authinfo-function
@findex nntp-send-authinfo
@vindex nntp-authinfo-file
This function will be used to send @samp{AUTHINFO} to the @sc{nntp}
server.  The default function is @code{nntp-send-authinfo}, which looks
through your @file{~/.authinfo} (or whatever you've set the
@code{nntp-authinfo-file} variable to) for applicable entries.  If none
are found, it will prompt you for a login name and a password.  The
format of the @file{~/.authinfo} file is (almost) the same as the
@code{ftp} @file{~/.netrc} file, which is defined in the @code{ftp}
manual page, but here are the salient facts:

@enumerate
@item
The file contains one or more line, each of which define one server.

@item
Each line may contain an arbitrary number of token/value pairs.  
@end enumerate

The valid tokens include @samp{machine}, @samp{login}, @samp{password},
@samp{default}.  Gnus introduce two new tokens, not present in the
original @file{.netrc}/@code{ftp} syntax, namely @samp{port} and
@samp{force}.  (This is the only way the @file{.authinfo} file format
deviates from the @file{.netrc} file format.) @samp{port} is used to
indicate what port on the server the credentials apply to, @samp{force}
is explained below.

Here's an example file:

@example
machine news.uio.no login larsi password geheimnis
machine nntp.ifi.uio.no login larsi force yes
@end example

The token/value pairs may appear in any order; @samp{machine} doesn't
have to be first, for instance.

In this example, both login name and password have been supplied for the
former server, while the latter has only the login name listed, and the
user will be prompted for the password.  The latter also has the
@samp{force} tag, which means that the authinfo will be sent to the
@var{nntp} server upon connection; the default (i.e., when there is not
@samp{force} tag) is to not send authinfo to the @var{nntp} server
until the @var{nntp} server asks for it.

You can also add @samp{default} lines that will apply to all servers
that don't have matching @samp{machine} lines.

@example
default force yes
@end example

This will force sending @samp{AUTHINFO} commands to all servers not
previously mentioned.

Remember to not leave the @file{~/.authinfo} file world-readable.

@item nntp-server-action-alist
@vindex nntp-server-action-alist
This is a list of regexps to match on server types and actions to be
taken when matches are made.  For instance, if you want Gnus to beep
every time you connect to innd, you could say something like:

@lisp
(setq nntp-server-action-alist
      '(("innd" (ding))))
@end lisp

You probably don't want to do that, though.

The default value is

@lisp
'(("nntpd 1\\.5\\.11t"
   (remove-hook 'nntp-server-opened-hook 'nntp-send-mode-reader)))
@end lisp

This ensures that Gnus doesn't send the @code{MODE READER} command to
nntpd 1.5.11t, since that command chokes that server, I've been told.

@item nntp-maximum-request
@vindex nntp-maximum-request
If the @sc{nntp} server doesn't support @sc{nov} headers, this backend
will collect headers by sending a series of @code{head} commands.  To
speed things up, the backend sends lots of these commands without
waiting for reply, and then reads all the replies.  This is controlled
by the @code{nntp-maximum-request} variable, and is 400 by default.  If
your network is buggy, you should set this to 1.

@item nntp-connection-timeout
@vindex nntp-connection-timeout
If you have lots of foreign @code{nntp} groups that you connect to
regularly, you're sure to have problems with @sc{nntp} servers not
responding properly, or being too loaded to reply within reasonable
time.  This is can lead to awkward problems, which can be helped
somewhat by setting @code{nntp-connection-timeout}.  This is an integer
that says how many seconds the @code{nntp} backend should wait for a
connection before giving up.  If it is @code{nil}, which is the default,
no timeouts are done.

@c @item nntp-command-timeout
@c @vindex nntp-command-timeout
@c @cindex PPP connections
@c @cindex dynamic IP addresses
@c If you're running Gnus on a machine that has a dynamically assigned
@c address, Gnus may become confused.  If the address of your machine
@c changes after connecting to the @sc{nntp} server, Gnus will simply sit
@c waiting forever for replies from the server.  To help with this
@c unfortunate problem, you can set this command to a number.  Gnus will
@c then, if it sits waiting for a reply from the server longer than that
@c number of seconds, shut down the connection, start a new one, and resend
@c the command.  This should hopefully be transparent to the user.  A
@c likely number is 30 seconds.
@c
@c @item nntp-retry-on-break
@c @vindex nntp-retry-on-break
@c If this variable is non-@code{nil}, you can also @kbd{C-g} if Gnus
@c hangs.  This will have much the same effect as the command timeout
@c described above.

@item nntp-server-hook
@vindex nntp-server-hook
This hook is run as the last step when connecting to an @sc{nntp}
server.

@findex nntp-open-rlogin
@findex nntp-open-telnet
@findex nntp-open-network-stream
@item nntp-open-connection-function
@vindex nntp-open-connection-function
This function is used to connect to the remote system.  Four pre-made
functions are supplied:

@table @code
@item nntp-open-network-stream
This is the default, and simply connects to some port or other on the
remote system.

@item nntp-open-rlogin
Does an @samp{rlogin} on the
remote system, and then does a @samp{telnet} to the @sc{nntp} server
available there.

@code{nntp-open-rlogin}-related variables:

@table @code

@item nntp-rlogin-program
@vindex nntp-rlogin-program
Program used to log in on remote machines.  The default is @samp{rsh},
but @samp{ssh} is a popular alternative.

@item nntp-rlogin-parameters
@vindex nntp-rlogin-parameters
This list will be used as the parameter list given to @code{rsh}.

@item nntp-rlogin-user-name
@vindex nntp-rlogin-user-name
User name on the remote system.

@end table

@item nntp-open-telnet
Does a @samp{telnet} to the remote system and then another @samp{telnet}
to get to the @sc{nntp} server.

@code{nntp-open-telnet}-related variables:

@table @code
@item nntp-telnet-command
@vindex nntp-telnet-command
Command used to start @code{telnet}.

@item nntp-telnet-switches
@vindex nntp-telnet-switches
List of strings to be used as the switches to the @code{telnet} command.

@item nntp-telnet-user-name
@vindex nntp-telnet-user-name
User name for log in on the remote system.

@item nntp-telnet-passwd
@vindex nntp-telnet-passwd
Password to use when logging in.

@item nntp-telnet-parameters
@vindex nntp-telnet-parameters
A list of strings executed as a command after logging in
via @code{telnet}.

@item nntp-telnet-shell-prompt
@vindex nntp-telnet-shell-prompt
Regexp matching the shell prompt on the remote machine.  The default is
@samp{bash\\|\$ *\r?$\\|> *\r?}.

@item nntp-open-telnet-envuser
@vindex nntp-open-telnet-envuser
If non-@code{nil}, the @code{telnet} session (client and server both)
will support the @code{ENVIRON} option and not prompt for login name.
This works for Solaris @code{telnet}, for instance.

@end table

@findex nntp-open-ssl-stream
@item nntp-open-ssl-stream
Opens a connection to a server over a @dfn{secure} channel.  To use this
you must have SSLay installed
(@file{ftp://ftp.psy.uq.oz.au/pub/Crypto/SSL}, and you also need
@file{ssl.el} (from the W3 distributeion, for instance).  You then
define a server as follows:

@lisp
;; Type `C-c C-c' after you've finished editing.
;;
;; "snews" is port 563 and is predefined in our /etc/services
;;
(nntp "snews.bar.com"
      (nntp-open-connection-function nntp-open-ssl-stream)
      (nntp-port-number "snews")
      (nntp-address "snews.bar.com"))
@end lisp

@end table

@item nntp-end-of-line
@vindex nntp-end-of-line
String to use as end-of-line marker when talking to the @sc{nntp}
server.  This is @samp{\r\n} by default, but should be @samp{\n} when
using @code{rlogin} to talk to the server.

@item nntp-rlogin-user-name
@vindex nntp-rlogin-user-name
User name on the remote system when using the @code{rlogin} connect
function.

@item nntp-address
@vindex nntp-address
The address of the remote system running the @sc{nntp} server.

@item nntp-port-number
@vindex nntp-port-number
Port number to connect to when using the @code{nntp-open-network-stream}
connect function.

@item nntp-buggy-select
@vindex nntp-buggy-select
Set this to non-@code{nil} if your select routine is buggy.

@item nntp-nov-is-evil
@vindex nntp-nov-is-evil
If the @sc{nntp} server does not support @sc{nov}, you could set this
variable to @code{t}, but @code{nntp} usually checks automatically whether @sc{nov}
can be used.

@item nntp-xover-commands
@vindex nntp-xover-commands
@cindex nov
@cindex XOVER
List of strings used as commands to fetch @sc{nov} lines from a
server.  The default value of this variable is @code{("XOVER"
"XOVERVIEW")}.

@item nntp-nov-gap
@vindex nntp-nov-gap
@code{nntp} normally sends just one big request for @sc{nov} lines to
the server.  The server responds with one huge list of lines.  However,
if you have read articles 2-5000 in the group, and only want to read
article 1 and 5001, that means that @code{nntp} will fetch 4999 @sc{nov}
lines that you will not need.  This variable says how
big a gap between two consecutive articles is allowed to be before the
@code{XOVER} request is split into several request.  Note that if your
network is fast, setting this variable to a really small number means
that fetching will probably be slower.  If this variable is @code{nil},
@code{nntp} will never split requests.  The default is 5.

@item nntp-prepare-server-hook
@vindex nntp-prepare-server-hook
A hook run before attempting to connect to an @sc{nntp} server.

@item nntp-warn-about-losing-connection
@vindex nntp-warn-about-losing-connection
If this variable is non-@code{nil}, some noise will be made when a
server closes connection.

@item nntp-record-commands
@vindex nntp-record-commands
If non-@code{nil}, @code{nntp} will log all commands it sends to the
@sc{nntp} server (along with a timestep) in the @samp{*nntp-log*}
buffer.  This is useful if you are debugging a Gnus/@sc{nntp} connection
that doesn't seem to work.

@end table


@node News Spool
@subsection News Spool
@cindex nnspool
@cindex news spool

Subscribing to a foreign group from the local spool is extremely easy,
and might be useful, for instance, to speed up reading groups that
contain very big articles---@samp{alt.binaries.pictures.furniture}, for
instance.

Anyways, you just specify @code{nnspool} as the method and @code{""} (or
anything else) as the address.

If you have access to a local spool, you should probably use that as the
native select method (@pxref{Finding the News}).  It is normally faster
than using an @code{nntp} select method, but might not be.  It depends.
You just have to try to find out what's best at your site.

@table @code

@item nnspool-inews-program
@vindex nnspool-inews-program
Program used to post an article.

@item nnspool-inews-switches
@vindex nnspool-inews-switches
Parameters given to the inews program when posting an article.

@item nnspool-spool-directory
@vindex nnspool-spool-directory
Where @code{nnspool} looks for the articles.  This is normally
@file{/usr/spool/news/}.

@item nnspool-nov-directory
@vindex nnspool-nov-directory
Where @code{nnspool} will look for @sc{nov} files.  This is normally
@file{/usr/spool/news/over.view/}.

@item nnspool-lib-dir
@vindex nnspool-lib-dir
Where the news lib dir is (@file{/usr/lib/news/} by default).

@item nnspool-active-file
@vindex nnspool-active-file
The path to the active file.

@item nnspool-newsgroups-file
@vindex nnspool-newsgroups-file
The path to the group descriptions file.

@item nnspool-history-file
@vindex nnspool-history-file
The path to the news history file.

@item nnspool-active-times-file
@vindex nnspool-active-times-file
The path to the active date file.

@item nnspool-nov-is-evil
@vindex nnspool-nov-is-evil
If non-@code{nil}, @code{nnspool} won't try to use any @sc{nov} files
that it finds.

@item nnspool-sift-nov-with-sed
@vindex nnspool-sift-nov-with-sed
@cindex sed
If non-@code{nil}, which is the default, use @code{sed} to get the
relevant portion from the overview file.  If nil, @code{nnspool} will
load the entire file into a buffer and process it there.

@end table


@node Getting Mail
@section Getting Mail
@cindex reading mail
@cindex mail

Reading mail with a newsreader---isn't that just plain WeIrD? But of
course.

@menu
* Mail in a Newsreader::         Important introductory notes.  
* Getting Started Reading Mail:: A simple cookbook example.
* Splitting Mail::               How to create mail groups.
* Mail Sources::                 How to tell Gnus where to get mail from.
* Mail Backend Variables::       Variables for customizing mail handling.
* Fancy Mail Splitting::         Gnus can do hairy splitting of incoming mail.
* Group Mail Splitting::         Use group customize to drive mail splitting.
* Incorporating Old Mail::       What about the old mail you have?
* Expiring Mail::                Getting rid of unwanted mail.
* Washing Mail::                 Removing gruft from the mail you get.
* Duplicates::                   Dealing with duplicated mail.
* Not Reading Mail::             Using mail backends for reading other files.
* Choosing a Mail Backend::      Gnus can read a variety of mail formats.
@end menu


@node Mail in a Newsreader
@subsection Mail in a Newsreader

If you are used to traditional mail readers, but have decided to switch 
to reading mail with Gnus, you may find yourself experiencing something
of a culture shock.

Gnus does not behave like traditional mail readers.  If you want to make 
it behave that way, you can, but it's an uphill battle.

Gnus, by default, handles all its groups using the same approach.  This
approach is very newsreaderly---you enter a group, see the new/unread
messages, and when you read the messages, they get marked as read, and
you don't see them any more.  (Unless you explicitly ask for them.)

In particular, you do not do anything explicitly to delete messages.

Does this mean that all the messages that have been marked as read are
deleted?  How awful!

But, no, it means that old messages are @dfn{expired} according to some
scheme or other.  For news messages, the expire process is controlled by 
the news administrator; for mail, the expire process is controlled by
you.  The expire process for mail is covered in depth in @pxref{Expiring
Mail}.

What many Gnus users find, after using it a while for both news and
mail, is that the transport mechanism has very little to do with how
they want to treat a message.

Many people subscribe to several mailing lists.  These are transported
via SMTP, and are therefore mail.  But we might go for weeks without
answering, or even reading these messages very carefully.  We may not
need to save them because if we should need to read one again, they are
archived somewhere else.

Some people have local news groups which have only a handful of readers.
These are transported via @sc{nntp}, and are therefore news.  But we may need
to read and answer a large fraction of the messages very carefully in
order to do our work.  And there may not be an archive, so we may need
to save the interesting messages the same way we would personal mail.

The important distinction turns out to be not the transport mechanism,
but other factors such as how interested we are in the subject matter,
or how easy it is to retrieve the message if we need to read it again.

Gnus provides many options for sorting mail into ``groups'' which behave
like newsgroups, and for treating each group (whether mail or news)
differently.

Some users never get comfortable using the Gnus (ahem) paradigm and wish
that Gnus should grow up and be a male, er, mail reader.  It is possible
to whip Gnus into a more mailreaderly being, but, as said before, it's
not easy.  People who prefer proper mail readers should try @sc{vm}
instead, which is an excellent, and proper, mail reader.

I don't mean to scare anybody off, but I want to make it clear that you
may be required to learn a new way of thinking about messages.  After
you've been subjected to The Gnus Way, you will come to love it.  I can
guarantee it.  (At least the guy who sold me the Emacs Subliminal
Brain-Washing Functions that I've put into Gnus did guarantee it.  You
Will Be Assimilated.  You Love Gnus.  You Love The Gnus Mail Way.
You Do.)


@node Getting Started Reading Mail
@subsection Getting Started Reading Mail

It's quite easy to use Gnus to read your new mail.  You just plonk the
mail backend of your choice into @code{gnus-secondary-select-methods},
and things will happen automatically.

For instance, if you want to use @code{nnml} (which is a "one file per
mail" backend), you could put the following in your @file{.gnus} file:

@lisp
(setq gnus-secondary-select-methods
      '((nnml "private")))
@end lisp

Now, the next time you start Gnus, this backend will be queried for new
articles, and it will move all the messages in your spool file to its
directory, which is @code{~/Mail/} by default.  The new group that will
be created (@samp{mail.misc}) will be subscribed, and you can read it
like any other group.

You will probably want to split the mail into several groups, though:

@lisp
(setq nnmail-split-methods
      '(("junk" "^From:.*Lars Ingebrigtsen")
        ("crazy" "^Subject:.*die\\|^Organization:.*flabby")
        ("other" "")))
@end lisp

This will result in three new @code{nnml} mail groups being created:
@samp{nnml:junk}, @samp{nnml:crazy}, and @samp{nnml:other}.  All the
mail that doesn't fit into the first two groups will be placed in the
last group.

This should be sufficient for reading mail with Gnus.  You might want to
give the other sections in this part of the manual a perusal, though.
Especially @pxref{Choosing a Mail Backend} and @pxref{Expiring Mail}.


@node Splitting Mail
@subsection Splitting Mail
@cindex splitting mail
@cindex mail splitting

@vindex nnmail-split-methods
The @code{nnmail-split-methods} variable says how the incoming mail is
to be split into groups.

@lisp
(setq nnmail-split-methods
  '(("mail.junk" "^From:.*Lars Ingebrigtsen")
    ("mail.crazy" "^Subject:.*die\\|^Organization:.*flabby")
    ("mail.other" "")))
@end lisp

This variable is a list of lists, where the first element of each of
these lists is the name of the mail group (they do not have to be called
something beginning with @samp{mail}, by the way), and the second
element is a regular expression used on the header of each mail to
determine if it belongs in this mail group.  The first string may
contain @samp{\\1} forms, like the ones used by @code{replace-match} to
insert sub-expressions from the matched text.  For instance:

@lisp
("list.\\1" "From:.* \\(.*\\)-list@@majordomo.com")
@end lisp

The second element can also be a function.  In that case, it will be
called narrowed to the headers with the first element of the rule as the
argument.  It should return a non-@code{nil} value if it thinks that the
mail belongs in that group.

The last of these groups should always be a general one, and the regular
expression should @emph{always} be @samp{} so that it matches any mails
that haven't been matched by any of the other regexps.  (These rules are
processed from the beginning of the alist toward the end.  The first
rule to make a match will "win", unless you have crossposting enabled.
In that case, all matching rules will "win".)

If you like to tinker with this yourself, you can set this variable to a
function of your choice.  This function will be called without any
arguments in a buffer narrowed to the headers of an incoming mail
message.  The function should return a list of group names that it
thinks should carry this mail message.

Note that the mail backends are free to maul the poor, innocent,
incoming headers all they want to.  They all add @code{Lines} headers;
some add @code{X-Gnus-Group} headers; most rename the Unix mbox
@code{From<SPACE>} line to something else.

@vindex nnmail-crosspost
The mail backends all support cross-posting.  If several regexps match,
the mail will be ``cross-posted'' to all those groups.
@code{nnmail-crosspost} says whether to use this mechanism or not.  Note
that no articles are crossposted to the general (@samp{}) group.

@vindex nnmail-crosspost-link-function
@cindex crosspost
@cindex links
@code{nnmh} and @code{nnml} makes crossposts by creating hard links to
the crossposted articles.  However, not all file systems support hard
links.  If that's the case for you, set
@code{nnmail-crosspost-link-function} to @code{copy-file}.  (This
variable is @code{add-name-to-file} by default.)

@kindex M-x nnmail-split-history
@kindex nnmail-split-history
If you wish to see where the previous mail split put the messages, you
can use the @kbd{M-x nnmail-split-history} command.  If you wish to see
where re-spooling messages would put the messages, you can use
@code{gnus-summary-respool-trace} and related commands (@pxref{Mail
Group Commands}). 

Gnus gives you all the opportunity you could possibly want for shooting
yourself in the foot.  Let's say you create a group that will contain
all the mail you get from your boss.  And then you accidentally
unsubscribe from the group.  Gnus will still put all the mail from your
boss in the unsubscribed group, and so, when your boss mails you ``Have
that report ready by Monday or you're fired!'', you'll never see it and,
come Tuesday, you'll still believe that you're gainfully employed while
you really should be out collecting empty bottles to save up for next
month's rent money.


@node Mail Sources
@subsection Mail Sources

Mail can be gotten from many different sources---the mail spool, from a
POP mail server, from a procmail directory, or from a maildir, for
instance.

@menu
* Mail Source Specifiers::       How to specify what a mail source is.
* Mail Source Customization::    Some variables that influence things.
* Fetching Mail::                Using the mail source specifiers.
@end menu


@node Mail Source Specifiers
@subsubsection Mail Source Specifiers
@cindex POP
@cindex mail server
@cindex procmail
@cindex mail spool
@cindex mail source

You tell Gnus how to fetch mail by setting @code{mail-sources}
(@pxref{Fetching Mail}) to a @dfn{mail source specifier}.

Here's an example:

@lisp
(pop :server "pop3.mailserver.com" :user "myname")
@end lisp

As can be observed, a mail source specifier is a list where the first
element is a @dfn{mail source type}, followed by an arbitrary number of
@dfn{keywords}.  Keywords that are not explicitly specified are given
default values.

The following mail source types are available:

@table @code
@item file
Get mail from a single file; typically from the mail spool.

Keywords:

@table @code
@item :path
The path of the file.  Defaults to the value of the @code{MAIL}
environment variable or @file{/usr/mail/spool/user-name}.
@end table

An example file mail source:

@lisp
(file :path "/usr/spool/mail/user-name")
@end lisp

Or using the default path:

@lisp
(file)
@end lisp

If the mail spool file is not located on the local machine, it's best to 
use POP or @sc{imap} or the like to fetch the mail.  You can not use ange-ftp 
file names here---it has no way to lock the mail spool while moving the
mail.

If it's impossible to set up a proper server, you can use ssh instead.

@lisp
(setq mail-sources
      '((file :prescript "ssh host bin/getmail >%t")))
@end lisp

The @samp{getmail} script would look something like the following:

@example
#!/bin/sh
#  getmail - move mail from spool to stdout
#  flu@@iki.fi

MOVEMAIL=/usr/lib/emacs/20.3/i386-redhat-linux/movemail
TMP=$HOME/Mail/tmp
rm -f $TMP; $MOVEMAIL $MAIL $TMP >/dev/null && cat $TMP
@end example

Alter this script to fit find the @samp{movemail} you want to use.


@item directory
Get mail from several files in a directory.  This is typically used when
you have procmail split the incoming mail into several files.  Setting
@code{nnmail-scan-directory-mail-source-once} to non-nil force Gnus to
scan the mail source only once.

Keywords:

@table @code
@item :path
The path of the directory where the files are.  There is no default
value.

@item :suffix
Only files ending with this suffix are used.  The default is
@samp{.spool}.

@item :predicate
Only files that have this predicate return non-@code{nil} are returned.
The default is @code{identity}.  This is used as an additional
filter---only files that have the right suffix @emph{and} satisfy this
predicate are considered.

@item :prescript
@itemx :postscript
Script run before/after fetching mail.

@end table

An example directory mail source:

@lisp
(directory :path "/home/user-name/procmail-dir/"
           :suffix ".prcml")
@end lisp

@item pop
Get mail from a POP server.

Keywords:

@table @code
@item :server
The name of the POP server.  The default is taken from the
@code{MAILHOST} environment variable.

@item :port
The port number of the POP server.  This can be a number (eg,
@samp{:port 1234}) or a string (eg, @samp{:port "pop3"}).  If it is a
string, it should be a service name as listed in @file{/etc/services} on
Unix systems.  The default is @samp{"pop3"}.

@item :user
The user name to give to the POP server.  The default is the login
name.

@item :password
The password to give to the POP server.  If not specified, the user is
prompted.

@item :program
The program to use to fetch mail from the POP server.  This is should be
a @code{format}-like string.  Here's an example:

@example
fetchmail %u@@%s -P %p %t
@end example

The valid format specifier characters are:

@table @samp
@item t
The name of the file the mail is to be moved to.  This must always be
included in this string.

@item s
The name of the server.

@item P
The port number of the server.

@item u
The user name to use.

@item p
The password to use.
@end table

The values used for these specs are taken from the values you give the
corresponding keywords.

@item :prescript
A script to be run before fetching the mail.  The syntax is the same as
the @code{:program} keyword.  This can also be a function to be run.

@item :postscript
A script to be run after fetching the mail.  The syntax is the same as
the @code{:program} keyword.  This can also be a function to be run.

@item :function
The function to use to fetch mail from the POP server.  The function is
called with one parameter---the name of the file where the mail should
be moved to.

@item :authentication
This can be either the symbol @code{password} or the symbol @code{apop}
and says what authentication scheme to use.  The default is
@code{password}.

@end table

If the @code{:program} and @code{:function} keywords aren't specified,
@code{pop3-movemail} will be used.

Here are some examples.  Fetch from the default POP server, using the
default user name, and default fetcher:

@lisp
(pop)
@end lisp

Fetch from a named server with a named user and password:

@lisp
(pop :server "my.pop.server"
     :user "user-name" :password "secret")
@end lisp

Use @samp{movemail} to move the mail:

@lisp
(pop :program "movemail po:%u %t %p")
@end lisp

@item maildir
Get mail from a maildir.  This is a type of mailbox that is supported by
at least qmail and postfix, where each file in a special directory
contains exactly one mail.

Keywords:

@table @code
@item :path
The path of the directory where the mails are stored.  The default is
taken from the @code{MAILDIR} environment variable or
@samp{~/Maildir/}.
@item :subdirs
The subdirectories of the Maildir.  The default is
@samp{("new" "cur")}.

@c If you sometimes look at your mail through a pop3 daemon before fetching
@c them with Gnus, you may also have to fetch your mails from the
@c @code{cur} directory inside the maildir, like in the first example
@c below.

You can also get mails from remote hosts (because maildirs don't suffer
from locking problems).

@end table

Two example maildir mail sources:

@lisp
(maildir :path "/home/user-name/Maildir/" :subdirs ("cur" "new"))
@end lisp

@lisp
(maildir :path "/user@@remotehost.org:~/Maildir/" :subdirs ("new"))
@end lisp

@item imap
Get mail from a @sc{imap} server.  If you don't want to use @sc{imap} as
intended, as a network mail reading protocol (ie with nnimap), for some
reason or other, Gnus let you treat it similar to a POP server and
fetches articles from a given @sc{imap} mailbox.

Keywords:

@table @code
@item :server
The name of the @sc{imap} server.  The default is taken from the
@code{MAILHOST} environment variable.

@item :port
The port number of the @sc{imap} server.  The default is @samp{143}, or
@samp{993} for SSL connections.

@item :user
The user name to give to the @sc{imap} server.  The default is the login
name.

@item :password
The password to give to the @sc{imap} server.  If not specified, the user is
prompted.

@item :stream
What stream to use for connecting to the server, this is one of the
symbols in @code{imap-stream-alist}.  Right now, this means
@samp{kerberos4}, @samp{ssl} or the default @samp{network}.

@item :authentication
Which authenticator to use for authenticating to the server, this is one
of the symbols in @code{imap-authenticator-alist}.  Right now, this
means @samp{kerberos4}, @samp{cram-md5}, @samp{anonymous} or the default
@samp{login}.

@item :mailbox
The name of the mailbox to get mail from.  The default is @samp{INBOX}
which normally is the mailbox which receive incoming mail.

@item :predicate
The predicate used to find articles to fetch.  The default, @samp{UNSEEN
UNDELETED}, is probably the best choice for most people, but if you
sometimes peek in your mailbox with a @sc{imap} client and mark some
articles as read (or; SEEN) you might want to set this to @samp{nil}.
Then all articles in the mailbox is fetched, no matter what.  For a
complete list of predicates, see RFC 2060 §6.4.4.

@item :fetchflag
How to flag fetched articles on the server, the default @samp{\Deleted}
will mark them as deleted, an alternative would be @samp{\Seen} which
would simply mark them as read.  These are the two most likely choices,
but more flags are defined in RFC 2060 §2.3.2.

@item :dontexpunge
If non-nil, don't remove all articles marked as deleted in the mailbox
after finishing the fetch.

@end table

An example @sc{imap} mail source:

@lisp
(imap :server "mail.mycorp.com" :stream kerberos4 :fetchflag "\\Seen")
@end lisp

@item webmail
Get mail from a webmail server, such as www.hotmail.com,
webmail.netscape.com, www.netaddress.com, www.my-deja.com.

NOTE: Now mail.yahoo.com provides POP3 service, so @sc{pop} mail source
is suggested.

NOTE: Webmail largely depends cookies. A "one-line-cookie" patch is
required for url "4.0pre.46".

WARNING: Mails may lost.  NO WARRANTY.

Keywords:

@table @code
@item :subtype
The type of the webmail server.  The default is @code{hotmail}.  The
alternatives are @code{netscape}, @code{netaddress}, @code{my-deja}.

@item :user
The user name to give to the webmail server.  The default is the login
name.

@item :password
The password to give to the webmail server.  If not specified, the user is
prompted.

@item :dontexpunge
If non-nil, only fetch unread articles and don't move them to trash
folder after finishing the fetch.

@end table

An example webmail source:

@lisp
(webmail :subtype 'hotmail :user "user-name" :password "secret")
@end lisp
@end table

@table @dfn
@item Common Keywords
Common keywords can be used in any type of mail source.

Keywords:

@table @code
@item :plugged
If non-nil, fetch the mail even when Gnus is unplugged.  If you use
directory source to get mail, you can specify it as in this example:

@lisp
(setq mail-sources
      '((directory :path "/home/pavel/.Spool/" 
                   :suffix ""
                   :plugged t)))
@end lisp

Gnus will then fetch your mail even when you are unplugged.  This is
useful when you use local mail and news.

@end table
@end table

@subsubsection Function Interface

Some of the above keywords specify a Lisp function to be executed.
For each keyword @code{:foo}, the Lisp variable @code{foo} is bound to
the value of the keyword while the function is executing.  For example,
consider the following mail-source setting:

@lisp
(setq mail-sources '((pop :user "jrl"
                          :server "pophost" :function fetchfunc)))
@end lisp

While the function @code{fetchfunc} is executing, the symbol @code{user}
is bound to @code{"jrl"}, and the symbol @code{server} is bound to
@code{"pophost"}.  The symbols @code{port}, @code{password},
@code{program}, @code{prescript}, @code{postscript}, @code{function},
and @code{authentication} are also bound (to their default values).

See above for a list of keywords for each type of mail source.


@node Mail Source Customization
@subsubsection Mail Source Customization

The following is a list of variables that influence how the mail is
fetched.  You would normally not need to set or change any of these
variables.

@table @code
@item mail-source-crash-box
@vindex mail-source-crash-box
File where mail will be stored while processing it.  The default is
@file{~/.emacs-mail-crash-box}.

@item mail-source-delete-incoming
@vindex mail-source-delete-incoming
If non-@code{nil}, delete incoming files after handling them.

@item mail-source-directory
@vindex mail-source-directory
Directory where files (if any) will be stored.  The default is
@file{~/Mail/}.  At present, the only thing this is used for is to say
where the incoming files will be stored if the previous variable is
@code{nil}.

@item mail-source-incoming-file-prefix
@vindex mail-source-incoming-file-prefix
Prefix for file name for storing incoming mail.  The default is
@file{Incoming}, in which case files will end up with names like
@file{Incoming30630D_} or @file{Incoming298602ZD}.  This is really only
relevant if @code{mail-source-delete-incoming} is @code{nil}.

@item mail-source-default-file-modes
@vindex mail-source-default-file-modes
All new mail files will get this file mode.  The default is 384.

@end table


@node Fetching Mail
@subsubsection Fetching Mail

@vindex mail-sources
@vindex nnmail-spool-file
The way to actually tell Gnus where to get new mail from is to set
@code{mail-sources} to a list of mail source specifiers
(@pxref{Mail Source Specifiers}).

If this variable (and the obsolescent @code{nnmail-spool-file}) is
@code{nil}, the mail backends will never attempt to fetch mail by
themselves.

If you want to fetch mail both from your local spool as well as a POP
mail server, you'd say something like:

@lisp
(setq mail-sources
      '((file)
        (pop :server "pop3.mail.server"
             :password "secret")))
@end lisp

Or, if you don't want to use any of the keyword defaults:

@lisp
(setq mail-sources
      '((file :path "/var/spool/mail/user-name")
        (pop :server "pop3.mail.server"
             :user "user-name"
             :port "pop3"
             :password "secret")))
@end lisp


When you use a mail backend, Gnus will slurp all your mail from your
inbox and plonk it down in your home directory.  Gnus doesn't move any
mail if you're not using a mail backend---you have to do a lot of magic
invocations first.  At the time when you have finished drawing the
pentagram, lightened the candles, and sacrificed the goat, you really
shouldn't be too surprised when Gnus moves your mail.



@node Mail Backend Variables
@subsection Mail Backend Variables

These variables are (for the most part) pertinent to all the various
mail backends.

@table @code
@vindex nnmail-read-incoming-hook
@item nnmail-read-incoming-hook
The mail backends all call this hook after reading new mail.  You can
use this hook to notify any mail watch programs, if you want to.

@vindex nnmail-split-hook
@item nnmail-split-hook
@findex article-decode-encoded-words
@findex RFC 1522 decoding
@findex RFC 2047 decoding
Hook run in the buffer where the mail headers of each message is kept
just before the splitting based on these headers is done.  The hook is
free to modify the buffer contents in any way it sees fit---the buffer
is discarded after the splitting has been done, and no changes performed
in the buffer will show up in any files.
@code{gnus-article-decode-encoded-words} is one likely function to add
to this hook.

@vindex nnmail-pre-get-new-mail-hook
@vindex nnmail-post-get-new-mail-hook
@item nnmail-pre-get-new-mail-hook
@itemx nnmail-post-get-new-mail-hook
These are two useful hooks executed when treating new incoming
mail---@code{nnmail-pre-get-new-mail-hook} (is called just before
starting to handle the new mail) and
@code{nnmail-post-get-new-mail-hook} (is called when the mail handling
is done).  Here's and example of using these two hooks to change the
default file modes the new mail files get:

@lisp
(add-hook 'gnus-pre-get-new-mail-hook
          (lambda () (set-default-file-modes 511)))

(add-hook 'gnus-post-get-new-mail-hook
          (lambda () (set-default-file-modes 551)))
@end lisp

@item nnmail-use-long-file-names
@vindex nnmail-use-long-file-names
If non-@code{nil}, the mail backends will use long file and directory
names.  Groups like @samp{mail.misc} will end up in directories
(assuming use of @code{nnml} backend) or files (assuming use of
@code{nnfolder} backend) like @file{mail.misc}.  If it is @code{nil},
the same group will end up in @file{mail/misc}.

@item nnmail-delete-file-function
@vindex nnmail-delete-file-function
@findex delete-file
Function called to delete files.  It is @code{delete-file} by default.

@item nnmail-cache-accepted-message-ids
@vindex nnmail-cache-accepted-message-ids
If non-@code{nil}, put the @code{Message-ID}s of articles imported into
the backend (via @code{Gcc}, for instance) into the mail duplication
discovery cache.  The default is @code{nil}.

@end table


@node Fancy Mail Splitting
@subsection Fancy Mail Splitting
@cindex mail splitting
@cindex fancy mail splitting

@vindex nnmail-split-fancy
@findex nnmail-split-fancy
If the rather simple, standard method for specifying how to split mail
doesn't allow you to do what you want, you can set
@code{nnmail-split-methods} to @code{nnmail-split-fancy}.  Then you can
play with the @code{nnmail-split-fancy} variable.

Let's look at an example value of this variable first:

@lisp
;; Messages from the mailer daemon are not crossposted to any of
;; the ordinary groups.  Warnings are put in a separate group
;; from real errors.
(| ("from" mail (| ("subject" "warn.*" "mail.warning")
                   "mail.misc"))
   ;; Non-error messages are crossposted to all relevant
   ;; groups, but we don't crosspost between the group for the
   ;; (ding) list and the group for other (ding) related mail.
   (& (| (any "ding@@ifi\\.uio\\.no" "ding.list")
         ("subject" "ding" "ding.misc"))
      ;; Other mailing lists...
      (any "procmail@@informatik\\.rwth-aachen\\.de" "procmail.list")
      (any "SmartList@@informatik\\.rwth-aachen\\.de" "SmartList.list")
      ;; Both lists below have the same suffix, so prevent
      ;; cross-posting to mkpkg.list of messages posted only to 
      ;; the bugs- list, but allow cross-posting when the
      ;; message was really cross-posted.
      (any "bugs-mypackage@@somewhere" "mypkg.bugs")
      (any "mypackage@@somewhere\" - "bugs-mypackage" "mypkg.list")
      ;; People...
      (any "larsi@@ifi\\.uio\\.no" "people.Lars_Magne_Ingebrigtsen"))
   ;; Unmatched mail goes to the catch all group.
   "misc.misc")
@end lisp

This variable has the format of a @dfn{split}.  A split is a (possibly)
recursive structure where each split may contain other splits.  Here are
the five possible split syntaxes:

@enumerate

@item
@samp{group}: If the split is a string, that will be taken as a group
name.  Normal regexp match expansion will be done.  See below for
examples.

@item
@code{(@var{field} @var{value} @code{[-} @var{restrict}
@code{[@dots{}]}@code{]} @var{split})}: If the split is a list, the
first element of which is a string, then store the message as
specified by @var{split}, if header @var{field} (a regexp) contains
@var{value} (also a regexp).  If @var{restrict} (yet another regexp)
matches some string after @var{field} and before the end of the
matched @var{value}, the @var{split} is ignored.  If none of the
@var{restrict} clauses match, @var{split} is processed.

@item
@code{(| @var{split}@dots{})}: If the split is a list, and the first
element is @code{|} (vertical bar), then process each @var{split} until
one of them matches.  A @var{split} is said to match if it will cause
the mail message to be stored in one or more groups.

@item
@code{(& @var{split}@dots{})}: If the split is a list, and the first
element is @code{&}, then process all @var{split}s in the list.

@item
@code{junk}: If the split is the symbol @code{junk}, then don't save
this message.  Use with extreme caution.

@item
@code{(: @var{function} @var{arg1} @var{arg2} @dots{})}:  If the split is
a list, and the first element is @code{:}, then the second element will
be called as a function with @var{args} given as arguments.  The
function should return a @var{split}.

For instance, the following function could be used to split based on the
body of the messages:

@lisp
(defun split-on-body ()
  (save-excursion
    (set-buffer " *nnmail incoming*")
    (goto-char (point-min))
    (when (re-search-forward "Some.*string" nil t)
      "string.group")))
@end lisp

@item
@code{(! @var{func} @var{split})}: If the split is a list, and the first
element is @code{!}, then SPLIT will be processed, and FUNC will be
called as a function with the result of SPLIT as argument.  FUNC should
return a split.

@item
@code{nil}: If the split is @code{nil}, it is ignored.

@end enumerate

In these splits, @var{field} must match a complete field name.
@var{value} must match a complete word according to the fundamental mode
syntax table.  You can use @code{.*} in the regexps to match partial
field names or words.  In other words, all @var{value}'s are wrapped in
@samp{\<} and @samp{\>} pairs.

@vindex nnmail-split-abbrev-alist
@var{field} and @var{value} can also be lisp symbols, in that case they
are expanded as specified by the variable
@code{nnmail-split-abbrev-alist}.  This is an alist of cons cells, where
the @code{car} of a cell contains the key, and the @code{cdr} contains the associated
value.

@vindex nnmail-split-fancy-syntax-table
@code{nnmail-split-fancy-syntax-table} is the syntax table in effect
when all this splitting is performed.

If you want to have Gnus create groups dynamically based on some
information in the headers (i.e., do @code{replace-match}-like
substitutions in the group names), you can say things like:

@example
(any "debian-\\b\\(\\w+\\)@@lists.debian.org" "mail.debian.\\1")
@end example

In this example, messages sent to @samp{debian-foo@@lists.debian.org}
will be filed in @samp{mail.debian.foo}.

If the string contains the element @samp{\&}, then the previously
matched string will be substituted.  Similarly, the elements @samp{\\1}
up to @samp{\\9} will be substituted with the text matched by the
groupings 1 through 9.

@findex nnmail-split-fancy-with-parent
@code{nnmail-split-fancy-with-parent} is a function which allows you to
split followups into the same groups their parents are in.  Sometimes
you can't make splitting rules for all your mail.  For example, your
boss might send you personal mail regarding different projects you are
working on, and as you can't tell your boss to put a distinguishing
string into the subject line, you have to resort to manually moving the
messages into the right group.  With this function, you only have to do
it once per thread.

To use this feature, you have to set @code{nnmail-treat-duplicates} to a
non-nil value.  And then you can include
@code{nnmail-split-fancy-with-parent} using the colon feature, like so:
@lisp
(setq nnmail-split-fancy
      '(| (: nnmail-split-fancy-with-parent)
          ;; other splits go here
        ))
@end lisp

This feature works as follows: when @code{nnmail-treat-duplicates} is
non-nil, Gnus records the message id of every message it sees in the
file specified by the variable @code{nnmail-message-id-cache-file},
together with the group it is in (the group is omitted for non-mail
messages).  When mail splitting is invoked, the function
@code{nnmail-split-fancy-with-parent} then looks at the References (and
In-Reply-To) header of each message to split and searches the file
specified by @code{nnmail-message-id-cache-file} for the message ids.
When it has found a parent, it returns the corresponding group name.  It
is recommended that you set @code{nnmail-message-id-cache-length} to a
somewhat higher number than the default so that the message ids are
still in the cache.  (A value of 5000 appears to create a file some 300
kBytes in size.)  When @code{nnmail-cache-accepted-message-ids} is
non-nil, Gnus also records the message ids of moved articles, so that
the followup messages goes into the new group.


@node Group Mail Splitting
@subsection Group Mail Splitting
@cindex mail splitting
@cindex group mail splitting

@findex gnus-group-split
If you subscribe to dozens of mailing lists but you don't want to
maintain mail splitting rules manually, group mail splitting is for you.
You just have to set @var{to-list} and/or @var{to-address} in group
parameters or group customization and set @code{nnmail-split-methods} to
@code{gnus-group-split}.  This splitting function will scan all groups
for those parameters and split mail accordingly, i.e., messages posted
from or to the addresses specified in the parameters @var{to-list} or
@var{to-address} of a mail group will be stored in that group.

Sometimes, mailing lists have multiple addresses, and you may want mail
splitting to recognize them all: just set the @var{extra-aliases} group
parameter to the list of additional addresses and it's done.  If you'd
rather use a regular expression, set @var{split-regexp}.

All these parameters in a group will be used to create an
@code{nnmail-split-fancy} split, in which the @var{field} is @samp{any},
the @var{value} is a single regular expression that matches
@var{to-list}, @var{to-address}, all of @var{extra-aliases} and all
matches of @var{split-regexp}, and the @var{split} is the name of the
group.  @var{restrict}s are also supported: just set the
@var{split-exclude} parameter to a list of regular expressions.

If you can't get the right split to be generated using all these
parameters, or you just need something fancier, you can set the
parameter @var{split-spec} to an @code{nnmail-split-fancy} split.  In
this case, all other aforementioned parameters will be ignored by
@code{gnus-group-split}.  In particular, @var{split-spec} may be set to
@code{nil}, in which case the group will be ignored by
@code{gnus-group-split}.

@vindex gnus-group-split-default-catch-all-group
@code{gnus-group-split} will do cross-posting on all groups that match,
by defining a single @code{&} fancy split containing one split for each
group.  If a message doesn't match any split, it will be stored in the
group named in @code{gnus-group-split-default-catch-all-group}, unless
some group has @var{split-spec} set to @code{catch-all}, in which case
that group is used as the catch-all group.  Even though this variable is
often used just to name a group, it may also be set to an arbitrarily
complex fancy split (after all, a group name is a fancy split), and this
may be useful to split mail that doesn't go to any mailing list to
personal mail folders.  Note that this fancy split is added as the last
element of a @code{|} split list that also contains a @code{&} split
with the rules extracted from group parameters.

It's time for an example.  Assume the following group parameters have
been defined:

@example
nnml:mail.bar:
((to-address . "bar@@femail.com")
 (split-regexp . ".*@@femail\\.com"))
nnml:mail.foo:
((to-list . "foo@@nowhere.gov")
 (extra-aliases "foo@@localhost" "foo-redist@@home")
 (split-exclude "bugs-foo" "rambling-foo")
 (admin-address . "foo-request@@nowhere.gov"))
nnml:mail.others:
((split-spec . catch-all))
@end example

Setting @code{nnmail-split-methods} to @code{gnus-group-split} will
behave as if @code{nnmail-split-fancy} had been selected and variable
@code{nnmail-split-fancy} had been set as follows:

@lisp
(| (& (any "\\(bar@@femail\\.com\\|.*@@femail\\.com\\)" "mail.bar")
      (any "\\(foo@@nowhere\\.gov\\|foo@@localhost\\|foo-redist@@home\\)"
           - "bugs-foo" - "rambling-foo" "mail.foo"))
   "mail.others")
@end lisp

@findex gnus-group-split-fancy
If you'd rather not use group splitting for all your mail groups, you
may use it for only some of them, by using @code{nnmail-split-fancy}
splits like this:

@lisp
(: gnus-mlsplt-fancy GROUPS NO-CROSSPOST CATCH-ALL)
@end lisp

@var{groups} may be a regular expression or a list of group names whose
parameters will be scanned to generate the output split.
@var{no-crosspost} can be used to disable cross-posting; in this case, a
single @code{|} split will be output.  @var{catch-all} is the fallback
fancy split, used like @var{gnus-group-split-default-catch-all-group}.
If @var{catch-all} is @code{nil}, or if @var{split-regexp} matches the
empty string in any selected group, no catch-all split will be issued.
Otherwise, if some group has @var{split-spec} set to @code{catch-all},
this group will override the value of the @var{catch-all} argument.

@findex gnus-group-split-setup
Unfortunately, scanning all groups and their parameters can be quite
slow, especially considering that it has to be done for every message.
But don't despair!  The function @code{gnus-group-split-setup} can be
used to enable @code{gnus-group-split} in a much more efficient way.  It
sets @code{nnmail-split-methods} to @code{nnmail-split-fancy} and sets
@code{nnmail-split-fancy} to the split produced by
@code{gnus-group-split-fancy}.  Thus, the group parameters are only
scanned once, no matter how many messages are split.

@findex gnus-group-split-update
However, if you change group parameters, you'd have to update
@code{nnmail-split-fancy} manually.  You can do it by running
@code{gnus-group-split-update}.  If you'd rather have it updated
automatically, just tell @code{gnus-group-split-setup} to do it for
you.  For example, add to your @file{.gnus}:

@lisp
(gnus-group-split-setup AUTO-UPDATE CATCH-ALL)
@end lisp

If @var{auto-update} is non-@code{nil}, @code{gnus-group-split-update}
will be added to @code{nnmail-pre-get-new-mail-hook}, so you won't ever
have to worry about updating @code{nnmail-split-fancy} again.  If you
don't omit @var{catch-all} (it's optional; same as nil),
@code{gnus-group-split-default-catch-all-group} will be set to its
value.

@vindex gnus-group-split-updated-hook
Because you may want to change @code{nnmail-split-fancy} after it is set
by @code{gnus-group-split-update}, this function will run
@code{gnus-group-split-updated-hook} just before finishing.

@node Incorporating Old Mail
@subsection Incorporating Old Mail

Most people have lots of old mail stored in various file formats.  If
you have set up Gnus to read mail using one of the spiffy Gnus mail
backends, you'll probably wish to have that old mail incorporated into
your mail groups.

Doing so can be quite easy.

To take an example: You're reading mail using @code{nnml}
(@pxref{Mail Spool}), and have set @code{nnmail-split-methods} to a
satisfactory value (@pxref{Splitting Mail}).  You have an old Unix mbox
file filled with important, but old, mail.  You want to move it into
your @code{nnml} groups.

Here's how:

@enumerate
@item
Go to the group buffer.

@item
Type `G f' and give the path to the mbox file when prompted to create an
@code{nndoc} group from the mbox file (@pxref{Foreign Groups}).

@item
Type `SPACE' to enter the newly created group.

@item
Type `M P b' to process-mark all articles in this group's buffer
(@pxref{Setting Process Marks}).

@item
Type `B r' to respool all the process-marked articles, and answer
@samp{nnml} when prompted (@pxref{Mail Group Commands}).
@end enumerate

All the mail messages in the mbox file will now also be spread out over
all your @code{nnml} groups.  Try entering them and check whether things
have gone without a glitch.  If things look ok, you may consider
deleting the mbox file, but I wouldn't do that unless I was absolutely
sure that all the mail has ended up where it should be.

Respooling is also a handy thing to do if you're switching from one mail
backend to another.  Just respool all the mail in the old mail groups
using the new mail backend.


@node Expiring Mail
@subsection Expiring Mail
@cindex article expiry

Traditional mail readers have a tendency to remove mail articles when
you mark them as read, in some way.  Gnus takes a fundamentally
different approach to mail reading.

Gnus basically considers mail just to be news that has been received in
a rather peculiar manner.  It does not think that it has the power to
actually change the mail, or delete any mail messages.  If you enter a
mail group, and mark articles as ``read'', or kill them in some other
fashion, the mail articles will still exist on the system.  I repeat:
Gnus will not delete your old, read mail.  Unless you ask it to, of
course.

To make Gnus get rid of your unwanted mail, you have to mark the
articles as @dfn{expirable}.  This does not mean that the articles will
disappear right away, however.  In general, a mail article will be
deleted from your system if, 1) it is marked as expirable, AND 2) it is
more than one week old.  If you do not mark an article as expirable, it
will remain on your system until hell freezes over.  This bears
repeating one more time, with some spurious capitalizations: IF you do
NOT mark articles as EXPIRABLE, Gnus will NEVER delete those ARTICLES.

@vindex gnus-auto-expirable-newsgroups
You do not have to mark articles as expirable by hand.  Groups that
match the regular expression @code{gnus-auto-expirable-newsgroups} will
have all articles that you read marked as expirable automatically.  All
articles marked as expirable have an @samp{E} in the first
column in the summary buffer.

By default, if you have auto expiry switched on, Gnus will mark all the
articles you read as expirable, no matter if they were read or unread
before.  To avoid having articles marked as read marked as expirable
automatically, you can put something like the following in your
@file{.gnus} file:

@vindex gnus-mark-article-hook
@lisp
(remove-hook 'gnus-mark-article-hook
             'gnus-summary-mark-read-and-unread-as-read)
(add-hook 'gnus-mark-article-hook 'gnus-summary-mark-unread-as-read)
@end lisp

Note that making a group auto-expirable doesn't mean that all read
articles are expired---only the articles marked as expirable
will be expired.  Also note that using the @kbd{d} command won't make
groups expirable---only semi-automatic marking of articles as read will
mark the articles as expirable in auto-expirable groups.

Let's say you subscribe to a couple of mailing lists, and you want the
articles you have read to disappear after a while:

@lisp
(setq gnus-auto-expirable-newsgroups
      "mail.nonsense-list\\|mail.nice-list")
@end lisp

Another way to have auto-expiry happen is to have the element
@code{auto-expire} in the group parameters of the group.

If you use adaptive scoring (@pxref{Adaptive Scoring}) and
auto-expiring, you'll have problems.  Auto-expiring and adaptive scoring
don't really mix very well.

@vindex nnmail-expiry-wait
The @code{nnmail-expiry-wait} variable supplies the default time an
expirable article has to live.  Gnus starts counting days from when the
message @emph{arrived}, not from when it was sent.  The default is seven
days.

Gnus also supplies a function that lets you fine-tune how long articles
are to live, based on what group they are in.  Let's say you want to
have one month expiry period in the @samp{mail.private} group, a one day
expiry period in the @samp{mail.junk} group, and a six day expiry period
everywhere else:

@vindex nnmail-expiry-wait-function
@lisp
(setq nnmail-expiry-wait-function
      (lambda (group)
       (cond ((string= group "mail.private")
               31)
             ((string= group "mail.junk")
               1)
             ((string= group "important")
               'never)
             (t
               6))))
@end lisp

The group names this function is fed are ``unadorned'' group
names---no @samp{nnml:} prefixes and the like.

The @code{nnmail-expiry-wait} variable and
@code{nnmail-expiry-wait-function} function can either be a number (not
necessarily an integer) or one of the symbols @code{immediate} or
@code{never}.

You can also use the @code{expiry-wait} group parameter to selectively
change the expiry period (@pxref{Group Parameters}).

@vindex nnmail-expiry-target
The normal action taken when expiring articles is to delete them.
However, in some circumstances it might make more sense to move them to
other groups instead of deleting them.  The variable @code{nnmail-expiry-target}
(and the @code{expiry-target} group parameter) controls this.  The
variable supplies a default value for all groups, which can be
overridden for specific groups by the group parameter.
default value is @code{delete}, but this can also be a string (which
should be the name of the group the message should be moved to), or a
function (which will be called in a buffer narrowed to the message in
question, and with the name of the group being moved from as its
parameter) which should return a target -- either a group name or
@code{delete}.

Here's an example for specifying a group name:
@lisp
(setq nnmail-expiry-target "nnml:expired")
@end lisp


@vindex nnmail-keep-last-article
If @code{nnmail-keep-last-article} is non-@code{nil}, Gnus will never
expire the final article in a mail newsgroup.  This is to make life
easier for procmail users.

@vindex gnus-total-expirable-newsgroups
By the way: That line up there, about Gnus never expiring non-expirable
articles, is a lie.  If you put @code{total-expire} in the group
parameters, articles will not be marked as expirable, but all read
articles will be put through the expiry process.  Use with extreme
caution.  Even more dangerous is the
@code{gnus-total-expirable-newsgroups} variable.  All groups that match
this regexp will have all read articles put through the expiry process,
which means that @emph{all} old mail articles in the groups in question
will be deleted after a while.  Use with extreme caution, and don't come
crying to me when you discover that the regexp you used matched the
wrong group and all your important mail has disappeared.  Be a
@emph{man}!  Or a @emph{woman}!  Whatever you feel more comfortable
with!  So there!

Most people make most of their mail groups total-expirable, though.

@vindex gnus-inhibit-user-auto-expire
If @code{gnus-inhibit-user-auto-expire} is non-@code{nil}, user marking
commands will not mark an article as expirable, even if the group has
auto-expire turned on.


@node Washing Mail
@subsection Washing Mail
@cindex mail washing
@cindex list server brain damage
@cindex incoming mail treatment

Mailers and list servers are notorious for doing all sorts of really,
really stupid things with mail.  ``Hey, RFC 822 doesn't explicitly
prohibit us from adding the string @code{wE aRe ElItE!!!!!1!!} to the
end of all lines passing through our server, so let's do that!!!!1!''
Yes, but RFC 822 wasn't designed to be read by morons.  Things that were
considered to be self-evident were not discussed.  So.  Here we are.

Case in point:  The German version of Microsoft Exchange adds @samp{AW:
} to the subjects of replies instead of @samp{Re: }.  I could pretend to
be shocked and dismayed by this, but I haven't got the energy.  It is to
laugh.

Gnus provides a plethora of functions for washing articles while
displaying them, but it might be nicer to do the filtering before
storing the mail to disc.  For that purpose, we have three hooks and
various functions that can be put in these hooks.

@table @code
@item nnmail-prepare-incoming-hook
@vindex nnmail-prepare-incoming-hook
This hook is called before doing anything with the mail and is meant for
grand, sweeping gestures.  It is called in a buffer that contains all
the new, incoming mail.  Functions to be used include:

@table @code
@item nnheader-ms-strip-cr
@findex nnheader-ms-strip-cr
Remove trailing carriage returns from each line.  This is default on
Emacs running on MS machines.

@end table

@item nnmail-prepare-incoming-header-hook
@vindex nnmail-prepare-incoming-header-hook
This hook is called narrowed to each header.  It can be used when
cleaning up the headers.  Functions that can be used include:

@table @code
@item nnmail-remove-leading-whitespace
@findex nnmail-remove-leading-whitespace
Clear leading white space that ``helpful'' listservs have added to the
headers to make them look nice.  Aaah.

@item nnmail-remove-list-identifiers
@findex nnmail-remove-list-identifiers
Some list servers add an identifier---for example, @samp{(idm)}---to the
beginning of all @code{Subject} headers.  I'm sure that's nice for
people who use stone age mail readers.  This function will remove
strings that match the @code{nnmail-list-identifiers} regexp, which can
also be a list of regexp.  @code{nnmail-list-identifiers} may not contain
@code{\\(..\\)}.

For instance, if you want to remove the @samp{(idm)} and the
@samp{nagnagnag} identifiers:

@lisp
(setq nnmail-list-identifiers
      '("(idm)" "nagnagnag"))
@end lisp

This can also be done non-destructively with
@code{gnus-list-identifiers}, @xref{Article Hiding}.

@item nnmail-remove-tabs
@findex nnmail-remove-tabs
Translate all @samp{TAB} characters into @samp{SPACE} characters.

@item nnmail-fix-eudora-headers
@findex nnmail-fix-eudora-headers
@cindex Eudora
Eudora produces broken @code{References} headers, but OK
@code{In-Reply-To} headers.  This function will get rid of the
@code{References} headers.

@end table

@item nnmail-prepare-incoming-message-hook
@vindex nnmail-prepare-incoming-message-hook
This hook is called narrowed to each message.  Functions to be used
include:

@table @code
@item article-de-quoted-unreadable
@findex article-de-quoted-unreadable
Decode Quoted Readable encoding.

@end table
@end table


@node Duplicates
@subsection Duplicates

@vindex nnmail-treat-duplicates
@vindex nnmail-message-id-cache-length
@vindex nnmail-message-id-cache-file
@cindex duplicate mails
If you are a member of a couple of mailing lists, you will sometimes
receive two copies of the same mail.  This can be quite annoying, so
@code{nnmail} checks for and treats any duplicates it might find.  To do
this, it keeps a cache of old @code{Message-ID}s---
@code{nnmail-message-id-cache-file}, which is @file{~/.nnmail-cache} by
default.  The approximate maximum number of @code{Message-ID}s stored
there is controlled by the @code{nnmail-message-id-cache-length}
variable, which is 1000 by default.  (So 1000 @code{Message-ID}s will be
stored.) If all this sounds scary to you, you can set
@code{nnmail-treat-duplicates} to @code{warn} (which is what it is by
default), and @code{nnmail} won't delete duplicate mails.  Instead it
will insert a warning into the head of the mail saying that it thinks
that this is a duplicate of a different message.

This variable can also be a function.  If that's the case, the function
will be called from a buffer narrowed to the message in question with
the @code{Message-ID} as a parameter.  The function must return either
@code{nil}, @code{warn}, or @code{delete}.

You can turn this feature off completely by setting the variable to
@code{nil}.

If you want all the duplicate mails to be put into a special
@dfn{duplicates} group, you could do that using the normal mail split
methods:

@lisp
(setq nnmail-split-fancy
      '(| ;; Messages duplicates go to a separate group.
          ("gnus-warning" "duplication of message" "duplicate")
          ;; Message from daemons, postmaster, and the like to another.
          (any mail "mail.misc")
          ;; Other rules.
          [ ... ] ))
@end lisp

Or something like:
@lisp
(setq nnmail-split-methods
      '(("duplicates" "^Gnus-Warning:")
        ;; Other rules.
        [...]))
@end lisp

Here's a neat feature: If you know that the recipient reads her mail
with Gnus, and that she has @code{nnmail-treat-duplicates} set to
@code{delete}, you can send her as many insults as you like, just by
using a @code{Message-ID} of a mail that you know that she's already
received.  Think of all the fun!  She'll never see any of it!  Whee!


@node Not Reading Mail
@subsection Not Reading Mail

If you start using any of the mail backends, they have the annoying
habit of assuming that you want to read mail with them.  This might not
be unreasonable, but it might not be what you want.

If you set @code{mail-sources} and @code{nnmail-spool-file} to
@code{nil}, none of the backends will ever attempt to read incoming
mail, which should help.

@vindex nnbabyl-get-new-mail
@vindex nnmbox-get-new-mail
@vindex nnml-get-new-mail
@vindex nnmh-get-new-mail
@vindex nnfolder-get-new-mail
This might be too much, if, for instance, you are reading mail quite
happily with @code{nnml} and just want to peek at some old @sc{rmail}
file you have stashed away with @code{nnbabyl}.  All backends have
variables called backend-@code{get-new-mail}.  If you want to disable
the @code{nnbabyl} mail reading, you edit the virtual server for the
group to have a setting where @code{nnbabyl-get-new-mail} to @code{nil}.

All the mail backends will call @code{nn}*@code{-prepare-save-mail-hook}
narrowed to the article to be saved before saving it when reading
incoming mail.


@node Choosing a Mail Backend
@subsection Choosing a Mail Backend

Gnus will read the mail spool when you activate a mail group.  The mail
file is first copied to your home directory.  What happens after that
depends on what format you want to store your mail in.

There are five different mail backends in the standard Gnus, and more
backends are available separately.  The mail backend most people use
(because it is the fastest and most flexible) is @code{nnml}
(@pxref{Mail Spool}).

@menu
* Unix Mail Box::               Using the (quite) standard Un*x mbox.
* Rmail Babyl::                 Emacs programs use the rmail babyl format.
* Mail Spool::                  Store your mail in a private spool?
* MH Spool::                    An mhspool-like backend.
* Mail Folders::                Having one file for each group.
* Comparing Mail Backends::     An in-depth looks at pros and cons.
@end menu


@node Unix Mail Box
@subsubsection Unix Mail Box
@cindex nnmbox
@cindex unix mail box

@vindex nnmbox-active-file
@vindex nnmbox-mbox-file
The @dfn{nnmbox} backend will use the standard Un*x mbox file to store
mail.  @code{nnmbox} will add extra headers to each mail article to say
which group it belongs in.

Virtual server settings:

@table @code
@item nnmbox-mbox-file
@vindex nnmbox-mbox-file
The name of the mail box in the user's home directory.

@item nnmbox-active-file
@vindex nnmbox-active-file
The name of the active file for the mail box.

@item nnmbox-get-new-mail
@vindex nnmbox-get-new-mail
If non-@code{nil}, @code{nnmbox} will read incoming mail and split it
into groups.
@end table


@node Rmail Babyl
@subsubsection Rmail Babyl
@cindex nnbabyl
@cindex rmail mbox

@vindex nnbabyl-active-file
@vindex nnbabyl-mbox-file
The @dfn{nnbabyl} backend will use a babyl mail box (aka. @dfn{rmail
mbox}) to store mail.  @code{nnbabyl} will add extra headers to each
mail article to say which group it belongs in.

Virtual server settings:

@table @code
@item nnbabyl-mbox-file
@vindex nnbabyl-mbox-file
The name of the rmail mbox file.

@item nnbabyl-active-file
@vindex nnbabyl-active-file
The name of the active file for the rmail box.

@item nnbabyl-get-new-mail
@vindex nnbabyl-get-new-mail
If non-@code{nil}, @code{nnbabyl} will read incoming mail.
@end table


@node Mail Spool
@subsubsection Mail Spool
@cindex nnml
@cindex mail @sc{nov} spool

The @dfn{nnml} spool mail format isn't compatible with any other known
format.  It should be used with some caution.

@vindex nnml-directory
If you use this backend, Gnus will split all incoming mail into files,
one file for each mail, and put the articles into the corresponding
directories under the directory specified by the @code{nnml-directory}
variable.  The default value is @file{~/Mail/}.

You do not have to create any directories beforehand; Gnus will take
care of all that.

If you have a strict limit as to how many files you are allowed to store
in your account, you should not use this backend.  As each mail gets its
own file, you might very well occupy thousands of inodes within a few
weeks.  If this is no problem for you, and it isn't a problem for you
having your friendly systems administrator walking around, madly,
shouting ``Who is eating all my inodes?! Who? Who!?!'', then you should
know that this is probably the fastest format to use.  You do not have
to trudge through a big mbox file just to read your new mail.

@code{nnml} is probably the slowest backend when it comes to article
splitting.  It has to create lots of files, and it also generates
@sc{nov} databases for the incoming mails.  This makes it the fastest
backend when it comes to reading mail.

Virtual server settings:

@table @code
@item nnml-directory
@vindex nnml-directory
All @code{nnml} directories will be placed under this directory.

@item nnml-active-file
@vindex nnml-active-file
The active file for the @code{nnml} server.

@item nnml-newsgroups-file
@vindex nnml-newsgroups-file
The @code{nnml} group descriptions file.  @xref{Newsgroups File
Format}.

@item nnml-get-new-mail
@vindex nnml-get-new-mail
If non-@code{nil}, @code{nnml} will read incoming mail.

@item nnml-nov-is-evil
@vindex nnml-nov-is-evil
If non-@code{nil}, this backend will ignore any @sc{nov} files.

@item nnml-nov-file-name
@vindex nnml-nov-file-name
The name of the @sc{nov} files.  The default is @file{.overview}.

@item nnml-prepare-save-mail-hook
@vindex nnml-prepare-save-mail-hook
Hook run narrowed to an article before saving.

@end table

@findex nnml-generate-nov-databases
If your @code{nnml} groups and @sc{nov} files get totally out of whack,
you can do a complete update by typing @kbd{M-x
nnml-generate-nov-databases}.  This command will trawl through the
entire @code{nnml} hierarchy, looking at each and every article, so it
might take a while to complete.  A better interface to this
functionality can be found in the server buffer (@pxref{Server
Commands}).


@node MH Spool
@subsubsection MH Spool
@cindex nnmh
@cindex mh-e mail spool

@code{nnmh} is just like @code{nnml}, except that is doesn't generate
@sc{nov} databases and it doesn't keep an active file.  This makes
@code{nnmh} a @emph{much} slower backend than @code{nnml}, but it also
makes it easier to write procmail scripts for.

Virtual server settings:

@table @code
@item nnmh-directory
@vindex nnmh-directory
All @code{nnmh} directories will be located under this directory.

@item nnmh-get-new-mail
@vindex nnmh-get-new-mail
If non-@code{nil}, @code{nnmh} will read incoming mail.

@item nnmh-be-safe
@vindex nnmh-be-safe
If non-@code{nil}, @code{nnmh} will go to ridiculous lengths to make
sure that the articles in the folder are actually what Gnus thinks they
are.  It will check date stamps and stat everything in sight, so
setting this to @code{t} will mean a serious slow-down.  If you never
use anything but Gnus to read the @code{nnmh} articles, you do not have
to set this variable to @code{t}.
@end table


@node Mail Folders
@subsubsection Mail Folders
@cindex nnfolder
@cindex mbox folders
@cindex mail folders

@code{nnfolder} is a backend for storing each mail group in a separate
file.  Each file is in the standard Un*x mbox format.  @code{nnfolder}
will add extra headers to keep track of article numbers and arrival
dates.

Virtual server settings:

@table @code
@item nnfolder-directory
@vindex nnfolder-directory
All the @code{nnfolder} mail boxes will be stored under this directory.

@item nnfolder-active-file
@vindex nnfolder-active-file
The name of the active file.

@item nnfolder-newsgroups-file
@vindex nnfolder-newsgroups-file
The name of the group descriptions file.  @xref{Newsgroups File Format}.

@item nnfolder-get-new-mail
@vindex nnfolder-get-new-mail
If non-@code{nil}, @code{nnfolder} will read incoming mail.

@item nnfolder-save-buffer-hook
@vindex nnfolder-save-buffer-hook
@cindex backup files
Hook run before saving the folders.  Note that Emacs does the normal
backup renaming of files even with the @code{nnfolder} buffers.  If you
wish to switch this off, you could say something like the following in
your @file{.emacs} file:

@lisp
(defun turn-off-backup ()
  (set (make-local-variable 'backup-inhibited) t))

(add-hook 'nnfolder-save-buffer-hook 'turn-off-backup)
@end lisp

@item nnfolder-delete-mail-hook
@vindex nnfolder-delete-mail-hook
Hook run in a buffer narrowed to the message that is to be deleted.
This function can be used to copy the message to somewhere else, or to
extract some information from it before removing it.

@item nnfolder-nov-is-evil
@vindex nnfolder-nov-is-evil
If non-@code{nil}, this backend will ignore any @sc{nov} files.

@end table


@findex nnfolder-generate-active-file
@kindex M-x nnfolder-generate-active-file
If you have lots of @code{nnfolder}-like files you'd like to read with
@code{nnfolder}, you can use the @kbd{M-x nnfolder-generate-active-file}
command to make @code{nnfolder} aware of all likely files in
@code{nnfolder-directory}.  This only works if you use long file names,
though.

@node Comparing Mail Backends
@subsubsection Comparing Mail Backends

First, just for terminology, the @dfn{backend} is the common word for a
low-level access method---a transport, if you will, by which something
is acquired.  The sense is that one's mail has to come from somewhere,
and so selection of a suitable backend is required in order to get that
mail within spitting distance of Gnus.

The same concept exists for Usenet itself: Though access to articles is
typically done by @sc{nntp} these days, once upon a midnight dreary, everyone
in the world got at Usenet by running a reader on the machine where the
articles lay (the machine which today we call an @sc{nntp} server), and
access was by the reader stepping into the articles' directory spool
area directly.  One can still select between either the @code{nntp} or
@code{nnspool} backends, to select between these methods, if one happens
actually to live on the server (or can see its spool directly, anyway,
via NFS).

The goal in selecting a mail backend is to pick one which
simultaneously represents a suitable way of dealing with the original
format plus leaving mail in a form that is convenient to use in the
future.  Here are some high and low points on each:

@table @code
@item nnmbox

UNIX systems have historically had a single, very common, and well-
defined format.  All messages arrive in a single @dfn{spool file}, and
they are delineated by a line whose regular expression matches
@samp{^From_}.  (My notational use of @samp{_} is to indicate a space,
to make it clear in this instance that this is not the RFC-specified
@samp{From:} header.)  Because Emacs and therefore Gnus emanate
historically from the Unix environment, it is simplest if one does not
mess a great deal with the original mailbox format, so if one chooses
this backend, Gnus' primary activity in getting mail from the real spool
area to Gnus' preferred directory is simply to copy it, with no
(appreciable) format change in the process.  It is the ``dumbest'' way
to move mail into availability in the Gnus environment.  This makes it
fast to move into place, but slow to parse, when Gnus has to look at
what's where.

@item nnbabyl

Once upon a time, there was the DEC-10 and DEC-20, running operating
systems called TOPS and related things, and the usual (only?) mail
reading environment was a thing called Babyl.  I don't know what format
was used for mail landing on the system, but Babyl had its own internal
format to which mail was converted, primarily involving creating a
spool-file-like entity with a scheme for inserting Babyl-specific
headers and status bits above the top of each message in the file.
RMAIL was Emacs' first mail reader, it was written by Richard Stallman,
and Stallman came out of that TOPS/Babyl environment, so he wrote RMAIL
to understand the mail files folks already had in existence.  Gnus (and
VM, for that matter) continue to support this format because it's
perceived as having some good qualities in those mailer-specific
headers/status bits stuff.  RMAIL itself still exists as well, of
course, and is still maintained by Stallman.

Both of the above forms leave your mail in a single file on your
filesystem, and they must parse that entire file each time you take a
look at your mail.

@item nnml

@code{nnml} is the backend which smells the most as though you were
actually operating with an @code{nnspool}-accessed Usenet system.  (In
fact, I believe @code{nnml} actually derived from @code{nnspool} code,
lo these years ago.)  One's mail is taken from the original spool file,
and is then cut up into individual message files, 1:1.  It maintains a
Usenet-style active file (analogous to what one finds in an INN- or
CNews-based news system in (for instance) @file{/var/lib/news/active},
or what is returned via the @samp{NNTP LIST} verb) and also creates
@dfn{overview} files for efficient group entry, as has been defined for
@sc{nntp} servers for some years now.  It is slower in mail-splitting,
due to the creation of lots of files, updates to the @code{nnml} active
file, and additions to overview files on a per-message basis, but it is
extremely fast on access because of what amounts to the indexing support
provided by the active file and overviews.

@code{nnml} costs @dfn{inodes} in a big way; that is, it soaks up the
resource which defines available places in the filesystem to put new
files.  Sysadmins take a dim view of heavy inode occupation within
tight, shared filesystems.  But if you live on a personal machine where
the filesystem is your own and space is not at a premium, @code{nnml}
wins big.

It is also problematic using this backend if you are living in a
FAT16-based Windows world, since much space will be wasted on all these
tiny files.

@item nnmh

The Rand MH mail-reading system has been around UNIX systems for a very
long time; it operates by splitting one's spool file of messages into
individual files, but with little or no indexing support -- @code{nnmh}
is considered to be semantically equivalent to ``@code{nnml} without
active file or overviews''.  This is arguably the worst choice, because
one gets the slowness of individual file creation married to the
slowness of access parsing when learning what's new in one's groups.

@item nnfolder

Basically the effect of @code{nnfolder} is @code{nnmbox} (the first
method described above) on a per-group basis.  That is, @code{nnmbox}
itself puts *all* one's mail in one file; @code{nnfolder} provides a
little bit of optimization to this so that each of one's mail groups has
a Unix mail box file.  It's faster than @code{nnmbox} because each group
can be parsed separately, and still provides the simple Unix mail box
format requiring minimal effort in moving the mail around.  In addition, 
it maintains an ``active'' file making it much faster for Gnus to figure 
out how many messages there are in each separate group.

If you have groups that are expected to have a massive amount of
messages, @code{nnfolder} is not the best choice, but if you receive
only a moderate amount of mail, @code{nnfolder} is probably the most
friendly mail backend all over.

@end table


@node Browsing the Web
@section Browsing the Web
@cindex web
@cindex browsing the web
@cindex www
@cindex http

Web-based discussion forums are getting more and more popular.  On many
subjects, the web-based forums have become the most important forums,
eclipsing the importance of mailing lists and news groups.  The reason
is easy to understand---they are friendly to new users; you just point
and click, and there's the discussion.  With mailing lists, you have to
go through a cumbersome subscription procedure, and most people don't
even know what a news group is.

The problem with this scenario is that web browsers are not very good at 
being newsreaders.  They do not keep track of what articles you've read; 
they do not allow you to score on subjects you're interested in; they do 
not allow off-line browsing; they require you to click around and drive
you mad in the end.

So---if web browsers suck at reading discussion forums, why not use Gnus 
to do it instead?

Gnus has been getting a bit of a collection of backends for providing
interfaces to these sources.

@menu
* Web Searches::          Creating groups from articles that match a string.
* Slashdot::              Reading the Slashdot comments.
* Ultimate::              The Ultimate Bulletin Board systems.
* Web Archive::           Reading mailing list archived on web.
* Customizing w3::        Doing stuff to Emacs/w3 from Gnus.
@end menu

All the web sources require Emacs/w3 and the url library to work.

The main caveat with all these web sources is that they probably won't
work for a very long time.  Gleaning information from the @sc{html} data 
is guesswork at best, and when the layout is altered, the Gnus backend
will fail.  If you have reasonably new versions of these backends,
though, you should be ok.

One thing all these Web methods have in common is that the Web sources
are often down, unavailable or just plain too slow to be fun.  In those
cases, it makes a lot of sense to let the Gnus Agent (@pxref{Gnus
Unplugged}) handle downloading articles, and then you can read them at
leisure from your local disk.  No more World Wide Wait for you.


@node Web Searches
@subsection Web Searches
@cindex nnweb
@cindex DejaNews
@cindex Alta Vista
@cindex InReference
@cindex Usenet searches
@cindex searching the Usenet

It's, like, too neat to search the Usenet for articles that match a
string, but it, like, totally @emph{sucks}, like, totally, to use one of
those, like, Web browsers, and you, like, have to, rilly, like, look at
the commercials, so, like, with Gnus you can do @emph{rad}, rilly,
searches without having to use a browser.

The @code{nnweb} backend allows an easy interface to the mighty search
engine.  You create an @code{nnweb} group, enter a search pattern, and
then enter the group and read the articles like you would any normal
group.  The @kbd{G w} command in the group buffer (@pxref{Foreign
Groups}) will do this in an easy-to-use fashion.

@code{nnweb} groups don't really lend themselves to being solid
groups---they have a very fleeting idea of article numbers.  In fact,
each time you enter an @code{nnweb} group (not even changing the search
pattern), you are likely to get the articles ordered in a different
manner.  Not even using duplicate suppression (@pxref{Duplicate
Suppression}) will help, since @code{nnweb} doesn't even know the
@code{Message-ID} of the articles before reading them using some search
engines (DejaNews, for instance).  The only possible way to keep track
of which articles you've read is by scoring on the @code{Date}
header---mark all articles posted before the last date you read the
group as read.

If the search engine changes its output substantially, @code{nnweb}
won't be able to parse it and will fail.  One could hardly fault the Web
providers if they were to do this---their @emph{raison d'être} is to
make money off of advertisements, not to provide services to the
community.  Since @code{nnweb} washes the ads off all the articles, one
might think that the providers might be somewhat miffed.  We'll see.

You must have the @code{url} and @code{w3} package installed to be able
to use @code{nnweb}.

Virtual server variables:

@table @code
@item nnweb-type
@vindex nnweb-type
What search engine type is being used.  The currently supported types
are @code{dejanews}, @code{dejanewsold}, @code{altavista} and
@code{reference}.

@item nnweb-search
@vindex nnweb-search
The search string to feed to the search engine.

@item nnweb-max-hits
@vindex nnweb-max-hits
Advisory maximum number of hits per search to display.  The default is
100.

@item nnweb-type-definition
@vindex nnweb-type-definition
Type-to-definition alist.  This alist says what @code{nnweb} should do
with the various search engine types.  The following elements must be
present:

@table @code
@item article
Function to decode the article and provide something that Gnus
understands.

@item map
Function to create an article number to message header and URL alist.

@item search
Function to send the search string to the search engine.

@item address
The address the aforementioned function should send the search string
to.

@item id
Format string URL to fetch an article by @code{Message-ID}.
@end table

@end table


@node Slashdot
@subsection Slashdot
@cindex Slashdot
@cindex nnslashdot

Slashdot (@file{http://slashdot.org/}) is a popular news site, with
lively discussion following the news articles.  @code{nnslashdot} will
let you read this forum in a convenient manner.

The easiest way to read this source is to put something like the
following in your @file{.gnus.el} file:

@lisp
(setq gnus-secondary-select-methods
      '((nnslashdot "")))
@end lisp

This will make Gnus query the @code{nnslashdot} backend for new comments
and groups.  The @kbd{F} command will subscribe each new news article as
a new Gnus group, and you can read the comments by entering these
groups.  (Note that the default subscription method is to subscribe new
groups as zombies.  Other methods are available (@pxref{Subscription
Methods}).

If you want to remove an old @code{nnslashdot} group, the @kbd{G DEL}
command is the most handy tool (@pxref{Foreign Groups}).

When following up to @code{nnslashdot} comments (or posting new
comments), some light @sc{html}izations will be performed.  In
particular, text quoted with @samp{> } will be quoted with
@code{blockquote} instead, and signatures will have @code{br} added to
the end of each line.  Other than that, you can just write @sc{html}
directly into the message buffer.  Note that Slashdot filters out some
@sc{html} forms.

The following variables can be altered to change its behavior:

@table @code
@item nnslashdot-threaded
Whether @code{nnslashdot} should display threaded groups or not.  The
default is @code{t}.  To be able to display threads, @code{nnslashdot}
has to retrieve absolutely all comments in a group upon entry.  If a
threaded display is not required, @code{nnslashdot} will only retrieve
the comments that are actually wanted by the user.  Threading is nicer,
but much, much slower than untreaded.

@item nnslashdot-login-name
@vindex nnslashdot-login-name
The login name to use when posting.

@item nnslashdot-password
@vindex nnslashdot-password
The password to use when posting.

@item nnslashdot-directory
@vindex nnslashdot-directory
Where @code{nnslashdot} will store its files.  The default value is
@samp{~/News/slashdot/}.

@item nnslashdot-active-url
@vindex nnslashdot-active-url
The @sc{url} format string that will be used to fetch the information on 
news articles and comments.  The default is
@samp{http://slashdot.org/search.pl?section=&min=%d}.

@item nnslashdot-comments-url
@vindex nnslashdot-comments-url
The @sc{url} format string that will be used to fetch comments.  The
default is
@samp{http://slashdot.org/comments.pl?sid=%s&threshold=%d&commentsort=%d&mode=flat&startat=%d}.

@item nnslashdot-article-url
@vindex nnslashdot-article-url
The @sc{url} format string that will be used to fetch the news article.  The
default is
@samp{http://slashdot.org/article.pl?sid=%s&mode=nocomment}.

@item nnslashdot-threshold
@vindex nnslashdot-threshold
The score threshold.  The default is -1.

@item nnslashdot-group-number
@vindex nnslashdot-group-number
The number of old groups, in addition to the ten latest, to keep
updated.  The default is 0.

@end table



@node Ultimate
@subsection Ultimate
@cindex nnultimate
@cindex Ultimate Bulletin Board

The Ultimate Bulletin Board (@file{http://www.ultimatebb.com/}) is
probably the most popular Web bulletin board system used.  It has a
quite regular and nice interface, and it's possible to get the
information Gnus needs to keep groups updated.

The easiest way to get started with @code{nnultimate} is to say
something like the following in the group buffer:  @kbd{B nnultimate RET 
http://www.tcj.com/messboard/ubbcgi/ RET}.  (Substitute the @sc{url}
(not including @samp{Ultimate.cgi} or the like at the end) for a forum
you're interested in; there's quite a list of them on the Ultimate web
site.)  Then subscribe to the groups you're interested in from the
server buffer, and read them from the group buffer.

The following @code{nnultimate} variables can be altered:

@table @code
@item nnultimate-directory
@vindex nnultimate-directory
The directory where @code{nnultimate} stores its files.  The default is
@samp{~/News/ultimate/}.
@end table


@node Web Archive
@subsection Web Archive
@cindex nnwarchive
@cindex Web Archive

Some mailing lists only have archives on Web servers, such as
@file{http://www.egroups.com/} and
@file{http://www.mail-archive.com/}.  It has a quite regular and nice
interface, and it's possible to get the information Gnus needs to keep
groups updated.

The easiest way to get started with @code{nnwarchive} is to say
something like the following in the group buffer: @kbd{M-x
gnus-group-make-warchive-group RET an_egroup RET egroups RET
www.egroups.com RET your@@email.address RET}.  (Substitute the
@sc{an_egroup} with the mailing list you subscribed, the
@sc{your@@email.address} with your email address.), or to browse the
backend by @kbd{B nnwarchive RET mail-archive RET}.

The following @code{nnwarchive} variables can be altered:

@table @code
@item nnwarchive-directory
@vindex nnwarchive-directory
The directory where @code{nnwarchive} stores its files.  The default is
@samp{~/News/warchive/}.

@item nnwarchive-login
@vindex nnwarchive-login
The account name on the web server.

@item nnwarchive-passwd
@vindex nnwarchive-passwd
The password for your account on the web server.
@end table


@node Customizing w3
@subsection Customizing w3
@cindex w3
@cindex html
@cindex url
@cindex Netscape

Gnus uses the url library to fetch web pages and Emacs/w3 to display web 
pages.  Emacs/w3 is documented in its own manual, but there are some
things that may be more relevant for Gnus users.

For instance, a common question is how to make Emacs/w3 follow links
using the @code{browse-url} functions (which will call some external web 
browser like Netscape).  Here's one way:

@lisp
(eval-after-load "w3"
  '(progn
    (fset 'w3-fetch-orig (symbol-function 'w3-fetch))
    (defun w3-fetch (&optional url target)
      (interactive (list (w3-read-url-with-default)))
      (if (eq major-mode 'gnus-article-mode)
          (browse-url url)
        (w3-fetch-orig url target)))))
@end lisp

Put that in your @file{.emacs} file, and hitting links in w3-rendered
@sc{html} in the Gnus article buffers will use @code{browse-url} to
follow the link.


@node Other Sources
@section Other Sources

Gnus can do more than just read news or mail.  The methods described
below allow Gnus to view directories and files as if they were
newsgroups.

@menu
* Directory Groups::      You can read a directory as if it was a newsgroup.
* Anything Groups::       Dired?  Who needs dired?
* Document Groups::       Single files can be the basis of a group.
* SOUP::                  Reading @sc{soup} packets ``offline''.
* Mail-To-News Gateways:: Posting articles via mail-to-news gateways.
* IMAP::                  Using Gnus as a @sc{imap} client.
@end menu


@node Directory Groups
@subsection Directory Groups
@cindex nndir
@cindex directory groups

If you have a directory that has lots of articles in separate files in
it, you might treat it as a newsgroup.  The files have to have numerical
names, of course.

This might be an opportune moment to mention @code{ange-ftp} (and its
successor @code{efs}), that most wonderful of all wonderful Emacs
packages.  When I wrote @code{nndir}, I didn't think much about it---a
backend to read directories.  Big deal.

@code{ange-ftp} changes that picture dramatically.  For instance, if you
enter the @code{ange-ftp} file name
@file{/ftp.hpc.uh.edu:/pub/emacs/ding-list/} as the directory name,
@code{ange-ftp} or @code{efs} will actually allow you to read this
directory over at @samp{sina} as a newsgroup.  Distributed news ahoy!

@code{nndir} will use @sc{nov} files if they are present.

@code{nndir} is a ``read-only'' backend---you can't delete or expire
articles with this method.  You can use @code{nnmh} or @code{nnml} for
whatever you use @code{nndir} for, so you could switch to any of those
methods if you feel the need to have a non-read-only @code{nndir}.


@node Anything Groups
@subsection Anything Groups
@cindex nneething

From the @code{nndir} backend (which reads a single spool-like
directory), it's just a hop and a skip to @code{nneething}, which
pretends that any arbitrary directory is a newsgroup.  Strange, but
true.

When @code{nneething} is presented with a directory, it will scan this
directory and assign article numbers to each file.  When you enter such
a group, @code{nneething} must create ``headers'' that Gnus can use.
After all, Gnus is a newsreader, in case you're forgetting.
@code{nneething} does this in a two-step process.  First, it snoops each
file in question.  If the file looks like an article (i.e., the first
few lines look like headers), it will use this as the head.  If this is
just some arbitrary file without a head (e.g. a C source file),
@code{nneething} will cobble up a header out of thin air.  It will use
file ownership, name and date and do whatever it can with these
elements.

All this should happen automatically for you, and you will be presented
with something that looks very much like a newsgroup.  Totally like a
newsgroup, to be precise.  If you select an article, it will be displayed
in the article buffer, just as usual.

If you select a line that represents a directory, Gnus will pop you into
a new summary buffer for this @code{nneething} group.  And so on.  You can
traverse the entire disk this way, if you feel like, but remember that
Gnus is not dired, really, and does not intend to be, either.

There are two overall modes to this action---ephemeral or solid.  When
doing the ephemeral thing (i.e., @kbd{G D} from the group buffer), Gnus
will not store information on what files you have read, and what files
are new, and so on.  If you create a solid @code{nneething} group the
normal way with @kbd{G m}, Gnus will store a mapping table between
article numbers and file names, and you can treat this group like any
other groups.  When you activate a solid @code{nneething} group, you will
be told how many unread articles it contains, etc., etc.

Some variables:

@table @code
@item nneething-map-file-directory
@vindex nneething-map-file-directory
All the mapping files for solid @code{nneething} groups will be stored
in this directory, which defaults to @file{~/.nneething/}.

@item nneething-exclude-files
@vindex nneething-exclude-files
All files that match this regexp will be ignored.  Nice to use to exclude
auto-save files and the like, which is what it does by default.

@item nneething-include-files
@vindex nneething-include-files
Regexp saying what files to include in the group.  If this variable is
non-@code{nil}, only files matching this regexp will be included.

@item nneething-map-file
@vindex nneething-map-file
Name of the map files.
@end table


@node Document Groups
@subsection Document Groups
@cindex nndoc
@cindex documentation group
@cindex help group

@code{nndoc} is a cute little thing that will let you read a single file
as a newsgroup.  Several files types are supported:

@table @code
@cindex babyl
@cindex rmail mbox

@item babyl
The babyl (rmail) mail box.
@cindex mbox
@cindex Unix mbox

@item mbox
The standard Unix mbox file.

@cindex MMDF mail box
@item mmdf
The MMDF mail box format.

@item news
Several news articles appended into a file.

@item rnews
@cindex rnews batch files
The rnews batch transport format.
@cindex forwarded messages

@item forward
Forwarded articles.

@item nsmail
Netscape mail boxes.

@item mime-parts
MIME multipart messages.

@item standard-digest
The standard (RFC 1153) digest format.

@item slack-digest
Non-standard digest format---matches most things, but does it badly.
@end table

You can also use the special ``file type'' @code{guess}, which means
that @code{nndoc} will try to guess what file type it is looking at.
@code{digest} means that @code{nndoc} should guess what digest type the
file is.

@code{nndoc} will not try to change the file or insert any extra headers into
it---it will simply, like, let you use the file as the basis for a
group.  And that's it.

If you have some old archived articles that you want to insert into your
new & spiffy Gnus mail backend, @code{nndoc} can probably help you with
that.  Say you have an old @file{RMAIL} file with mail that you now want
to split into your new @code{nnml} groups.  You look at that file using
@code{nndoc} (using the @kbd{G f} command in the group buffer
(@pxref{Foreign Groups})), set the process mark on all the articles in
the buffer (@kbd{M P b}, for instance), and then re-spool (@kbd{B r})
using @code{nnml}.  If all goes well, all the mail in the @file{RMAIL}
file is now also stored in lots of @code{nnml} directories, and you can
delete that pesky @file{RMAIL} file.  If you have the guts!

Virtual server variables:

@table @code
@item nndoc-article-type
@vindex nndoc-article-type
This should be one of @code{mbox}, @code{babyl}, @code{digest},
@code{news}, @code{rnews}, @code{mmdf}, @code{forward}, @code{rfc934},
@code{rfc822-forward}, @code{mime-parts}, @code{standard-digest},
@code{slack-digest}, @code{clari-briefs}, @code{nsmail} or @code{guess}.

@item nndoc-post-type
@vindex nndoc-post-type
This variable says whether Gnus is to consider the group a news group or
a mail group.  There are two valid values:  @code{mail} (the default)
and @code{news}.
@end table

@menu
* Document Server Internals::   How to add your own document types.
@end menu


@node Document Server Internals
@subsubsection Document Server Internals

Adding new document types to be recognized by @code{nndoc} isn't
difficult.  You just have to whip up a definition of what the document
looks like, write a predicate function to recognize that document type,
and then hook into @code{nndoc}.

First, here's an example document type definition:

@example
(mmdf
 (article-begin .  "^\^A\^A\^A\^A\n")
 (body-end .  "^\^A\^A\^A\^A\n"))
@end example

The definition is simply a unique @dfn{name} followed by a series of
regexp pseudo-variable settings.  Below are the possible
variables---don't be daunted by the number of variables; most document
types can be defined with very few settings:

@table @code
@item first-article
If present, @code{nndoc} will skip past all text until it finds
something that match this regexp.  All text before this will be
totally ignored.

@item article-begin
This setting has to be present in all document type definitions.  It
says what the beginning of each article looks like.

@item head-begin-function
If present, this should be a function that moves point to the head of
the article.

@item nndoc-head-begin
If present, this should be a regexp that matches the head of the
article.

@item nndoc-head-end
This should match the end of the head of the article.  It defaults to
@samp{^$}---the empty line.

@item body-begin-function
If present, this function should move point to the beginning of the body
of the article.

@item body-begin
This should match the beginning of the body of the article.  It defaults
to @samp{^\n}.

@item body-end-function
If present, this function should move point to the end of the body of
the article.

@item body-end
If present, this should match the end of the body of the article.

@item file-end
If present, this should match the end of the file.  All text after this
regexp will be totally ignored.

@end table

So, using these variables @code{nndoc} is able to dissect a document
file into a series of articles, each with a head and a body.  However, a
few more variables are needed since not all document types are all that
news-like---variables needed to transform the head or the body into
something that's palatable for Gnus:

@table @code
@item prepare-body-function
If present, this function will be called when requesting an article.  It
will be called with point at the start of the body, and is useful if the
document has encoded some parts of its contents.

@item article-transform-function
If present, this function is called when requesting an article.  It's
meant to be used for more wide-ranging transformation of both head and
body of the article.

@item generate-head-function
If present, this function is called to generate a head that Gnus can
understand.  It is called with the article number as a parameter, and is
expected to generate a nice head for the article in question.  It is
called when requesting the headers of all articles.

@end table

Let's look at the most complicated example I can come up with---standard
digests:

@example
(standard-digest
 (first-article . ,(concat "^" (make-string 70 ?-) "\n\n+"))
 (article-begin . ,(concat "\n\n" (make-string 30 ?-) "\n\n+"))
 (prepare-body-function . nndoc-unquote-dashes)
 (body-end-function . nndoc-digest-body-end)
 (head-end . "^ ?$")
 (body-begin . "^ ?\n")
 (file-end . "^End of .*digest.*[0-9].*\n\\*\\*\\|^End of.*Digest *$")
 (subtype digest guess))
@end example

We see that all text before a 70-width line of dashes is ignored; all
text after a line that starts with that @samp{^End of} is also ignored;
each article begins with a 30-width line of dashes; the line separating
the head from the body may contain a single space; and that the body is
run through @code{nndoc-unquote-dashes} before being delivered.

To hook your own document definition into @code{nndoc}, use the
@code{nndoc-add-type} function.  It takes two parameters---the first is
the definition itself and the second (optional) parameter says where in
the document type definition alist to put this definition.  The alist is
traversed sequentially, and @code{nndoc-TYPE-type-p} is called for a given type @code{TYPE}.  So @code{nndoc-mmdf-type-p} is called to see whether a document
is of @code{mmdf} type, and so on.  These type predicates should return
@code{nil} if the document is not of the correct type; @code{t} if it is
of the correct type; and a number if the document might be of the
correct type.  A high number means high probability; a low number means
low probability with @samp{0} being the lowest valid number.


@node SOUP
@subsection SOUP
@cindex SOUP
@cindex offline

In the PC world people often talk about ``offline'' newsreaders.  These
are thingies that are combined reader/news transport monstrosities.
With built-in modem programs.  Yecchh!

Of course, us Unix Weenie types of human beans use things like
@code{uucp} and, like, @code{nntpd} and set up proper news and mail
transport things like Ghod intended.  And then we just use normal
newsreaders.

However, it can sometimes be convenient to do something that's a bit
easier on the brain if you have a very slow modem, and you're not really
that interested in doing things properly.

A file format called @sc{soup} has been developed for transporting news
and mail from servers to home machines and back again.  It can be a bit
fiddly.

First some terminology:

@table @dfn

@item server
This is the machine that is connected to the outside world and where you
get news and/or mail from.

@item home machine
This is the machine that you want to do the actual reading and responding
on.  It is typically not connected to the rest of the world in any way.

@item packet
Something that contains messages and/or commands.  There are two kinds
of packets:

@table @dfn
@item message packets
These are packets made at the server, and typically contain lots of
messages for you to read.  These are called @file{SoupoutX.tgz} by
default, where @var{x} is a number.

@item response packets
These are packets made at the home machine, and typically contains
replies that you've written.  These are called @file{SoupinX.tgz} by
default, where @var{x} is a number.

@end table

@end table


@enumerate

@item
You log in on the server and create a @sc{soup} packet.  You can either
use a dedicated @sc{soup} thingie (like the @code{awk} program), or you
can use Gnus to create the packet with its @sc{soup} commands (@kbd{O
s} and/or @kbd{G s b}; and then @kbd{G s p}) (@pxref{SOUP Commands}).

@item
You transfer the packet home.  Rail, boat, car or modem will do fine.

@item
You put the packet in your home directory.

@item
You fire up Gnus on your home machine using the @code{nnsoup} backend as
the native or secondary server.

@item
You read articles and mail and answer and followup to the things you
want (@pxref{SOUP Replies}).

@item
You do the @kbd{G s r} command to pack these replies into a @sc{soup}
packet.

@item
You transfer this packet to the server.

@item
You use Gnus to mail this packet out with the @kbd{G s s} command.

@item
You then repeat until you die.

@end enumerate

So you basically have a bipartite system---you use @code{nnsoup} for
reading and Gnus for packing/sending these @sc{soup} packets.

@menu
* SOUP Commands::     Commands for creating and sending @sc{soup} packets
* SOUP Groups::       A backend for reading @sc{soup} packets.
* SOUP Replies::      How to enable @code{nnsoup} to take over mail and news.
@end menu


@node SOUP Commands
@subsubsection SOUP Commands

These are commands for creating and manipulating @sc{soup} packets.

@table @kbd
@item G s b
@kindex G s b (Group)
@findex gnus-group-brew-soup
Pack all unread articles in the current group
(@code{gnus-group-brew-soup}).  This command understands the
process/prefix convention.

@item G s w
@kindex G s w (Group)
@findex gnus-soup-save-areas
Save all @sc{soup} data files (@code{gnus-soup-save-areas}).

@item G s s
@kindex G s s (Group)
@findex gnus-soup-send-replies
Send all replies from the replies packet
(@code{gnus-soup-send-replies}).

@item G s p
@kindex G s p (Group)
@findex gnus-soup-pack-packet
Pack all files into a @sc{soup} packet (@code{gnus-soup-pack-packet}).

@item G s r
@kindex G s r (Group)
@findex nnsoup-pack-replies
Pack all replies into a replies packet (@code{nnsoup-pack-replies}).

@item O s
@kindex O s (Summary)
@findex gnus-soup-add-article
This summary-mode command adds the current article to a @sc{soup} packet
(@code{gnus-soup-add-article}).  It understands the process/prefix
convention (@pxref{Process/Prefix}).

@end table


There are a few variables to customize where Gnus will put all these
thingies:

@table @code

@item gnus-soup-directory
@vindex gnus-soup-directory
Directory where Gnus will save intermediate files while composing
@sc{soup} packets.  The default is @file{~/SoupBrew/}.

@item gnus-soup-replies-directory
@vindex gnus-soup-replies-directory
This is what Gnus will use as a temporary directory while sending our
reply packets.  @file{~/SoupBrew/SoupReplies/} is the default.

@item gnus-soup-prefix-file
@vindex gnus-soup-prefix-file
Name of the file where Gnus stores the last used prefix.  The default is
@samp{gnus-prefix}.

@item gnus-soup-packer
@vindex gnus-soup-packer
A format string command for packing a @sc{soup} packet.  The default is
@samp{tar cf - %s | gzip > $HOME/Soupout%d.tgz}.

@item gnus-soup-unpacker
@vindex gnus-soup-unpacker
Format string command for unpacking a @sc{soup} packet.  The default is
@samp{gunzip -c %s | tar xvf -}.

@item gnus-soup-packet-directory
@vindex gnus-soup-packet-directory
Where Gnus will look for reply packets.  The default is @file{~/}.

@item gnus-soup-packet-regexp
@vindex gnus-soup-packet-regexp
Regular expression matching @sc{soup} reply packets in
@code{gnus-soup-packet-directory}.

@end table


@node SOUP Groups
@subsubsection @sc{soup} Groups
@cindex nnsoup

@code{nnsoup} is the backend for reading @sc{soup} packets.  It will
read incoming packets, unpack them, and put them in a directory where
you can read them at leisure.

These are the variables you can use to customize its behavior:

@table @code

@item nnsoup-tmp-directory
@vindex nnsoup-tmp-directory
When @code{nnsoup} unpacks a @sc{soup} packet, it does it in this
directory.  (@file{/tmp/} by default.)

@item nnsoup-directory
@vindex nnsoup-directory
@code{nnsoup} then moves each message and index file to this directory.
The default is @file{~/SOUP/}.

@item nnsoup-replies-directory
@vindex nnsoup-replies-directory
All replies will be stored in this directory before being packed into a
reply packet.  The default is @file{~/SOUP/replies/"}.

@item nnsoup-replies-format-type
@vindex nnsoup-replies-format-type
The @sc{soup} format of the replies packets.  The default is @samp{?n}
(rnews), and I don't think you should touch that variable.  I probably
shouldn't even have documented it.  Drats!  Too late!

@item nnsoup-replies-index-type
@vindex nnsoup-replies-index-type
The index type of the replies packet.  The default is @samp{?n}, which
means ``none''.  Don't fiddle with this one either!

@item nnsoup-active-file
@vindex nnsoup-active-file
Where @code{nnsoup} stores lots of information.  This is not an ``active
file'' in the @code{nntp} sense; it's an Emacs Lisp file.  If you lose
this file or mess it up in any way, you're dead.  The default is
@file{~/SOUP/active}.

@item nnsoup-packer
@vindex nnsoup-packer
Format string command for packing a reply @sc{soup} packet.  The default
is @samp{tar cf - %s | gzip > $HOME/Soupin%d.tgz}.

@item nnsoup-unpacker
@vindex nnsoup-unpacker
Format string command for unpacking incoming @sc{soup} packets.  The
default is @samp{gunzip -c %s | tar xvf -}.

@item nnsoup-packet-directory
@vindex nnsoup-packet-directory
Where @code{nnsoup} will look for incoming packets.  The default is
@file{~/}.

@item nnsoup-packet-regexp
@vindex nnsoup-packet-regexp
Regular expression matching incoming @sc{soup} packets.  The default is
@samp{Soupout}.

@item nnsoup-always-save
@vindex nnsoup-always-save
If non-@code{nil}, save the replies buffer after each posted message.

@end table


@node SOUP Replies
@subsubsection SOUP Replies

Just using @code{nnsoup} won't mean that your postings and mailings end
up in @sc{soup} reply packets automagically.  You have to work a bit
more for that to happen.

@findex nnsoup-set-variables
The @code{nnsoup-set-variables} command will set the appropriate
variables to ensure that all your followups and replies end up in the
@sc{soup} system.

In specific, this is what it does:

@lisp
(setq message-send-news-function 'nnsoup-request-post)
(setq message-send-mail-function 'nnsoup-request-mail)
@end lisp

And that's it, really.  If you only want news to go into the @sc{soup}
system you just use the first line.  If you only want mail to be
@sc{soup}ed you use the second.


@node Mail-To-News Gateways
@subsection Mail-To-News Gateways
@cindex mail-to-news gateways
@cindex gateways

If your local @code{nntp} server doesn't allow posting, for some reason
or other, you can post using one of the numerous mail-to-news gateways.
The @code{nngateway} backend provides the interface.

Note that you can't read anything from this backend---it can only be
used to post with.

Server variables:

@table @code
@item nngateway-address
@vindex nngateway-address
This is the address of the mail-to-news gateway.

@item nngateway-header-transformation
@vindex nngateway-header-transformation
News headers often have to be transformed in some odd way or other
for the mail-to-news gateway to accept it.  This variable says what
transformation should be called, and defaults to
@code{nngateway-simple-header-transformation}.  The function is called
narrowed to the headers to be transformed and with one parameter---the
gateway address.

This default function just inserts a new @code{To} header based on the
@code{Newsgroups} header and the gateway address.
For instance, an article with this @code{Newsgroups} header:

@example
Newsgroups: alt.religion.emacs
@end example

will get this @code{From} header inserted:

@example
To: alt-religion-emacs@@GATEWAY
@end example

The following pre-defined functions exist:

@findex nngateway-simple-header-transformation
@table @code

@item nngateway-simple-header-transformation
Creates a @code{To} header that looks like
@var{newsgroup}@@@code{nngateway-address}.

@findex nngateway-mail2news-header-transformation

@item nngateway-mail2news-header-transformation
Creates a @code{To} header that looks like
@code{nngateway-address}.

Here's an example:

@lisp
(setq gnus-post-method
      '(nngateway "mail2news@@replay.com"
                  (nngateway-header-transformation
                   nngateway-mail2news-header-transformation)))
@end lisp

@end table


@end table

So, to use this, simply say something like:

@lisp
(setq gnus-post-method '(nngateway "GATEWAY.ADDRESS"))
@end lisp



@node IMAP
@subsection @sc{imap}
@cindex nnimap
@cindex @sc{imap}

@sc{imap} is a network protocol for reading mail (or news, or ...),
think of it as a modernized @sc{nntp}.  Connecting to a @sc{imap} server
is much similar to connecting to a news server, you just specify the
network address of the server.

A server configuration in @code{~/.gnus} with a few @sc{imap} servers
might look something like this:

@lisp
(setq gnus-secondary-select-methods 
      '((nnimap "simpleserver") ; no special configuration
        ; perhaps a ssh port forwarded server:
        (nnimap "dolk"
                (nnimap-address "localhost")
                (nnimap-server-port 1430))
        ; a UW server running on localhost
        (nnimap "barbar"
                (nnimap-server-port 143)
                (nnimap-address "localhost")
                (nnimap-list-pattern ("INBOX" "mail/*")))
        ; anonymous public cyrus server:
        (nnimap "cyrus.andrew.cmu.edu"
                (nnimap-authenticator anonymous)
                (nnimap-list-pattern "archive.*")
                (nnimap-stream network))
        ; a ssl server on a non-standard port:
        (nnimap "vic20"
                (nnimap-address "vic20.somewhere.com")
                (nnimap-server-port 9930)
                (nnimap-stream ssl))))
@end lisp

The following variables can be used to create a virtual @code{nnimap}
server:

@table @code

@item nnimap-address
@vindex nnimap-address

The address of the remote @sc{imap} server.  Defaults to the virtual
server name if not specified.

@item nnimap-server-port
@vindex nnimap-server-port
Port on server to contact.  Defaults to port 143, or 993 for SSL.

Note that this should be a integer, example server specification:

@lisp
(nnimap "mail.server.com"
        (nnimap-server-port 4711))
@end lisp

@item nnimap-list-pattern
@vindex nnimap-list-pattern
String or list of strings of mailboxes to limit available groups to.
This is used when the server has very many mailboxes and you're only
interested in a few -- some servers export your home directory via
@sc{imap}, you'll probably want to limit the mailboxes to those in
@file{~/Mail/*} then.

The string can also be a cons of REFERENCE and the string as above, what
REFERENCE is used for is server specific, but on the University of
Washington server it's a directory that will be concatenated with the
mailbox.

Example server specification:

@lisp
(nnimap "mail.server.com"
        (nnimap-list-pattern ("INBOX" "Mail/*" "alt.sex.*" 
                               ("~friend/Mail/" . "list/*"))))
@end lisp

@item nnimap-stream
@vindex nnimap-stream
The type of stream used to connect to your server.  By default, nnimap
will detect and automatically use all of the below, with the exception
of SSL. (SSL is being replaced by STARTTLS, which can be automatically
detected, but it's not widely deployed yet).

Example server specification:

@lisp
(nnimap "mail.server.com"
        (nnimap-stream ssl))
@end lisp

Please note that the value of @code{nnimap-stream} is a symbol!

@itemize @bullet
@item
@dfn{gssapi:} Connect with GSSAPI (usually kerberos 5). Require the
@samp{imtest} program.
@item
@dfn{kerberos4:} Connect with kerberos 4. Require the @samp{imtest} program.
@item
@dfn{starttls:} Connect via the STARTTLS extension (similar to
SSL). Require the external library @samp{starttls.el} and program
@samp{starttls}.
@item
@dfn{ssl:} Connect through SSL. Require OpenSSL (the
program @samp{openssl}) or SSLeay (@samp{s_client}).
@item
@dfn{shell:} Use a shell command to start IMAP connection.
@item
@dfn{network:} Plain, TCP/IP network connection.
@end itemize

@vindex imap-kerberos4-program
The @samp{imtest} program is shipped with Cyrus IMAPD, nnimap support
both @samp{imtest} version 1.5.x and version 1.6.x.  The variable
@code{imap-kerberos4-program} contain parameters to pass to the imtest
program.

@vindex imap-ssl-program
For SSL connections, the OpenSSL program is available from
@file{http://www.openssl.org/}. OpenSSL was formerly known as SSLeay,
and nnimap support it too - altough the most recent versions of
SSLeay, 0.9.x, are known to have serious bugs making it
useless. Earlier versions, especially 0.8.x, of SSLeay are known to
work. The variable @code{imap-ssl-program} contain parameters to pass
to OpenSSL/SSLeay.

@vindex imap-shell-program
@vindex imap-shell-host
For IMAP connections using the @code{shell} stream, the variable
@code{imap-shell-program} specify what program to call.

@item nnimap-authenticator
@vindex nnimap-authenticator

The authenticator used to connect to the server.  By default, nnimap
will use the most secure authenticator your server is capable of.

Example server specification:

@lisp
(nnimap "mail.server.com"
        (nnimap-authenticator anonymous))
@end lisp

Please note that the value of @code{nnimap-authenticator} is a symbol!

@itemize @bullet
@item
@dfn{gssapi:} GSSAPI (usually kerberos 5) authentication. Require
external program @code{imtest}.
@item
@dfn{kerberos4:} Kerberos authentication. Require external program
@code{imtest}.
@item
@dfn{digest-md5:} Encrypted username/password via DIGEST-MD5. Require
external library @code{digest-md5.el}.
@item
@dfn{cram-md5:} Encrypted username/password via CRAM-MD5.
@item
@dfn{login:} Plain-text username/password via LOGIN.
@item
@dfn{anonymous:} Login as `anonymous', supplying your emailadress as password.
@end itemize

@item nnimap-expunge-on-close
@cindex Expunging
@vindex nnimap-expunge-on-close
Unlike Parmenides the @sc{imap} designers has decided that things that
doesn't exist actually does exist.  More specifically, @sc{imap} has
this concept of marking articles @code{Deleted} which doesn't actually
delete them, and this (marking them @code{Deleted}, that is) is what
nnimap does when you delete a article in Gnus (with @kbd{G DEL} or
similair).

Since the articles aren't really removed when we mark them with the
@code{Deleted} flag we'll need a way to actually delete them.  Feel like
running in circles yet?

Traditionally, nnimap has removed all articles marked as @code{Deleted}
when closing a mailbox but this is now configurable by this server
variable.

The possible options are:

@table @code

@item always
The default behaviour, delete all articles marked as "Deleted" when
closing a mailbox.
@item never
Never actually delete articles.  Currently there is no way of showing
the articles marked for deletion in nnimap, but other @sc{imap} clients
may allow you to do this.  If you ever want to run the EXPUNGE command
manually, @xref{Expunging mailboxes}.
@item ask
When closing mailboxes, nnimap will ask if you wish to expunge deleted
articles or not.

@end table

@item nnimap-authinfo-file
@vindex nnimap-authinfo-file

A file containing credentials used to log in on servers.  The format
is (almost) the same as the @code{ftp} @file{~/.netrc} file.  See
`nntp-authinfo-file' for exact syntax.

A file containing credentials used to log in on servers.  The format is
(almost) the same as the @code{ftp} @file{~/.netrc} file.  See the
variable @code{nntp-authinfo-file} for exact syntax; also see
@xref{NNTP}.

@end table

@menu
* Splitting in IMAP::     Splitting mail with nnimap.
* Editing IMAP ACLs::     Limiting/enabling other users access to a mailbox.
* Expunging mailboxes::   Equivalent of a "compress mailbox" button.
@end menu



@node Splitting in IMAP
@subsubsection Splitting in @sc{imap}
@cindex splitting imap mail

Splitting is something Gnus users has loved and used for years, and now
the rest of the world is catching up.  Yeah, dream on, not many
@sc{imap} server has server side splitting and those that have splitting
seem to use some non-standard protocol.  This means that @sc{imap}
support for Gnus has to do it's own splitting.

And it does.

Here are the variables of interest:

@table @code

@item nnimap-split-crosspost
@cindex splitting, crosspost
@cindex crosspost
@vindex nnimap-split-crosspost

If non-nil, do crossposting if several split methods match the mail.  If
nil, the first match in @code{nnimap-split-rule} found will be used.

Nnmail equivalent: @code{nnmail-crosspost}.

@item nnimap-split-inbox
@cindex splitting, inbox
@cindex inbox
@vindex nnimap-split-inbox

A string or a list of strings that gives the name(s) of @sc{imap}
mailboxes to split from.  Defaults to nil, which means that splitting is
disabled!

@lisp
(setq nnimap-split-inbox
      '("INBOX" ("~/friend/Mail" . "lists/*") "lists.imap"))
@end lisp

No nnmail equivalent.

@item nnimap-split-rule
@cindex Splitting, rules
@vindex nnimap-split-rule

New mail found in @code{nnimap-split-inbox} will be split according to
this variable.

This variable contains a list of lists, where the first element in the
sublist gives the name of the @sc{imap} mailbox to move articles
matching the regexp in the second element in the sublist.  Got that?
Neither did I, we need examples.

@lisp
(setq nnimap-split-rule
      '(("INBOX.nnimap"  "^Sender: owner-nnimap@@vic20.globalcom.se")
        ("INBOX.junk"    "^Subject:.*MAKE MONEY")
        ("INBOX.private" "")))
@end lisp

This will put all articles from the nnimap mailing list into mailbox
INBOX.nnimap, all articles containing MAKE MONEY in the Subject: line
into INBOX.spam and everything else in INBOX.private.

The first string may contain `\\1' forms, like the ones used by
replace-match to insert sub-expressions from the matched text.  For
instance:

@lisp
("INBOX.lists.\\1"     "^Sender: owner-\\([a-z-]+\\)@@")
@end lisp

The second element can also be a function.  In that case, it will be
called with the first element of the rule as the argument, in a buffer
containing the headers of the article.  It should return a non-nil value
if it thinks that the mail belongs in that group.

Nnmail users might recollect that the last regexp had to be empty to
match all articles (like in the example above).  This is not required in
nnimap.  Articles not matching any of the regexps will not be moved out
of your inbox.  (This might might affect performance if you keep lots of
unread articles in your inbox, since the splitting code would go over
them every time you fetch new mail.)

These rules are processed from the beginning of the alist toward the
end.  The first rule to make a match will "win", unless you have
crossposting enabled.  In that case, all matching rules will "win".

This variable can also have a function as its value, the function will
be called with the headers narrowed and should return a group where it
thinks the article should be splitted to.  See @code{nnimap-split-fancy}.

The splitting code tries to create mailboxes if it need too.

To allow for different split rules on different virtual servers, and
even different split rules in different inboxes on the same server,
the syntax of this variable have been extended along the lines of:

@lisp
(setq nnimap-split-rule
      '(("my1server"    (".*"    (("ding"    "ding@@gnus.org")
                                  ("junk"    "From:.*Simon")))
        ("my2server"    ("INBOX" nnimap-split-fancy))
        ("my[34]server" (".*"    (("private" "To:.*Simon")
                                  ("junk"    my-junk-func)))))
@end lisp

The virtual server name is in fact a regexp, so that the same rules
may apply to several servers.  In the example, the servers
@code{my3server} and @code{my4server} both use the same rules.
Similarly, the inbox string is also a regexp.  The actual splitting
rules are as before, either a function, or a list with group/regexp or
group/function elements.

Nnmail equivalent: @code{nnmail-split-methods}.

@item nnimap-split-predicate
@cindex splitting
@vindex nnimap-split-predicate

Mail matching this predicate in @code{nnimap-split-inbox} will be
splitted, it is a string and the default is @samp{UNSEEN UNDELETED}.

This might be useful if you use another @sc{imap} client to read mail in
your inbox but would like Gnus to split all articles in the inbox
regardless of readedness. Then you might change this to
@samp{UNDELETED}.

@item nnimap-split-fancy
@cindex splitting, fancy
@findex nnimap-split-fancy
@vindex nnimap-split-fancy

It's possible to set @code{nnimap-split-rule} to
@code{nnmail-split-fancy} if you want to use fancy
splitting. @xref{Fancy Mail Splitting}.

However, to be able to have different fancy split rules for nnmail and
nnimap backends you can set @code{nnimap-split-rule} to
@code{nnimap-split-fancy} and define the nnimap specific fancy split
rule in @code{nnimap-split-fancy}.

Example:

@lisp
(setq nnimap-split-rule 'nnimap-split-fancy
      nnimap-split-fancy ...)
@end lisp

Nnmail equivalent: @code{nnmail-split-fancy}.

@end table

@node Editing IMAP ACLs
@subsubsection Editing @sc{imap} ACLs
@cindex editing imap acls
@cindex Access Control Lists
@cindex Editing @sc{imap} ACLs
@kindex G l
@findex gnus-group-nnimap-edit-acl

ACL stands for Access Control List.  ACLs are used in @sc{imap} for
limiting (or enabling) other users access to your mail boxes.  Not all
@sc{imap} servers support this, this function will give an error if it
doesn't.

To edit a ACL for a mailbox, type @kbd{G l}
(@code{gnus-group-edit-nnimap-acl}) and you'll be presented with a ACL
editing window with detailed instructions.

Some possible uses:

@itemize @bullet
@item
Giving "anyone" the "lrs" rights (lookup, read, keep seen/unseen flags)
on your mailing list mailboxes enables other users on the same server to
follow the list without subscribing to it.
@item
At least with the Cyrus server, you are required to give the user
"anyone" posting ("p") capabilities to have "plussing" work (that is,
mail sent to user+mailbox@@domain ending up in the @sc{imap} mailbox
INBOX.mailbox).
@end itemize

@node Expunging mailboxes
@subsubsection Expunging mailboxes
@cindex expunging

@cindex Expunge
@cindex Manual expunging
@kindex G x
@findex gnus-group-nnimap-expunge

If you're using the @code{never} setting of @code{nnimap-expunge-close},
you may want the option of expunging all deleted articles in a mailbox
manually.  This is exactly what @kbd{G x} does.

Currently there is no way of showing deleted articles, you can just
delete them.



@node Combined Groups
@section Combined Groups

Gnus allows combining a mixture of all the other group types into bigger
groups.

@menu
* Virtual Groups::     Combining articles from many groups.
* Kibozed Groups::     Looking through parts of the newsfeed for articles.
@end menu


@node Virtual Groups
@subsection Virtual Groups
@cindex nnvirtual
@cindex virtual groups
@cindex merging groups

An @dfn{nnvirtual group} is really nothing more than a collection of
other groups.

For instance, if you are tired of reading many small groups, you can
put them all in one big group, and then grow tired of reading one
big, unwieldy group.  The joys of computing!

You specify @code{nnvirtual} as the method.  The address should be a
regexp to match component groups.

All marks in the virtual group will stick to the articles in the
component groups.  So if you tick an article in a virtual group, the
article will also be ticked in the component group from whence it came.
(And vice versa---marks from the component groups will also be shown in
the virtual group.)

Here's an example @code{nnvirtual} method that collects all Andrea Dworkin
newsgroups into one, big, happy newsgroup:

@lisp
(nnvirtual "^alt\\.fan\\.andrea-dworkin$\\|^rec\\.dworkin.*")
@end lisp

The component groups can be native or foreign; everything should work
smoothly, but if your computer explodes, it was probably my fault.

Collecting the same group from several servers might actually be a good
idea if users have set the Distribution header to limit distribution.
If you would like to read @samp{soc.motss} both from a server in Japan
and a server in Norway, you could use the following as the group regexp:

@example
"^nntp\\+server\\.jp:soc\\.motss$\\|^nntp\\+server\\.no:soc\\.motss$"
@end example

(Remember, though, that if you're creating the group with @kbd{G m}, you
shouldn't double the backslashes, and you should leave off the quote
characters at the beginning and the end of the string.)

This should work kinda smoothly---all articles from both groups should
end up in this one, and there should be no duplicates.  Threading (and
the rest) will still work as usual, but there might be problems with the
sequence of articles.  Sorting on date might be an option here
(@pxref{Selecting a Group}).

One limitation, however---all groups included in a virtual
group have to be alive (i.e., subscribed or unsubscribed).  Killed or
zombie groups can't be component groups for @code{nnvirtual} groups.

@vindex nnvirtual-always-rescan
If the @code{nnvirtual-always-rescan} is non-@code{nil},
@code{nnvirtual} will always scan groups for unread articles when
entering a virtual group.  If this variable is @code{nil} (which is the
default) and you read articles in a component group after the virtual
group has been activated, the read articles from the component group
will show up when you enter the virtual group.  You'll also see this
effect if you have two virtual groups that have a component group in
common.  If that's the case, you should set this variable to @code{t}.
Or you can just tap @code{M-g} on the virtual group every time before
you enter it---it'll have much the same effect.

@code{nnvirtual} can have both mail and news groups as component groups.
When responding to articles in @code{nnvirtual} groups, @code{nnvirtual}
has to ask the backend of the component group the article comes from
whether it is a news or mail backend.  However, when you do a @kbd{^},
there is typically no sure way for the component backend to know this,
and in that case @code{nnvirtual} tells Gnus that the article came from a
not-news backend.  (Just to be on the safe side.)

@kbd{C-c C-t} in the message buffer will insert the @code{Newsgroups}
line from the article you respond to in these cases.



@node Kibozed Groups
@subsection Kibozed Groups
@cindex nnkiboze
@cindex kibozing

@dfn{Kibozing} is defined by @sc{oed} as ``grepping through (parts of)
the news feed''.  @code{nnkiboze} is a backend that will do this for
you.  Oh joy!  Now you can grind any @sc{nntp} server down to a halt
with useless requests!  Oh happiness!

@kindex G k (Group)
To create a kibozed group, use the @kbd{G k} command in the group
buffer.

The address field of the @code{nnkiboze} method is, as with
@code{nnvirtual}, a regexp to match groups to be ``included'' in the
@code{nnkiboze} group.  That's where most similarities between @code{nnkiboze}
and @code{nnvirtual} end.

In addition to this regexp detailing component groups, an @code{nnkiboze} group
must have a score file to say what articles are to be included in
the group (@pxref{Scoring}).

@kindex M-x nnkiboze-generate-groups
@findex nnkiboze-generate-groups
You must run @kbd{M-x nnkiboze-generate-groups} after creating the
@code{nnkiboze} groups you want to have.  This command will take time.  Lots of
time.  Oodles and oodles of time.  Gnus has to fetch the headers from
all the articles in all the component groups and run them through the
scoring process to determine if there are any articles in the groups
that are to be part of the @code{nnkiboze} groups.

Please limit the number of component groups by using restrictive
regexps.  Otherwise your sysadmin may become annoyed with you, and the
@sc{nntp} site may throw you off and never let you back in again.
Stranger things have happened.

@code{nnkiboze} component groups do not have to be alive---they can be dead,
and they can be foreign.  No restrictions.

@vindex nnkiboze-directory
The generation of an @code{nnkiboze} group means writing two files in
@code{nnkiboze-directory}, which is @file{~/News/} by default.  One
contains the @sc{nov} header lines for all the articles in the group,
and the other is an additional @file{.newsrc} file to store information
on what groups have been searched through to find component articles.

Articles marked as read in the @code{nnkiboze} group will have
their @sc{nov} lines removed from the @sc{nov} file.


@node Gnus Unplugged
@section Gnus Unplugged
@cindex offline
@cindex unplugged
@cindex Agent
@cindex Gnus Agent
@cindex Gnus Unplugged

In olden times (ca. February '88), people used to run their newsreaders
on big machines with permanent connections to the net.  News transport
was dealt with by news servers, and all the newsreaders had to do was to
read news.  Believe it or not.

Nowadays most people read news and mail at home, and use some sort of
modem to connect to the net.  To avoid running up huge phone bills, it
would be nice to have a way to slurp down all the news and mail, hang up
the phone, read for several hours, and then upload any responses you
have to make.  And then you repeat the procedure.

Of course, you can use news servers for doing this as well.  I've used
@code{inn} together with @code{slurp}, @code{pop} and @code{sendmail}
for some years, but doing that's a bore.  Moving the news server
functionality up to the newsreader makes sense if you're the only person
reading news on a machine.

Using Gnus as an ``offline'' newsreader is quite simple.

@itemize @bullet
@item
First, set up Gnus as you would do if you were running it on a machine
that has full connection to the net.  Go ahead.  I'll still be waiting
here.

@item
Then, put the following magical incantation at the end of your
@file{.gnus.el} file:

@lisp
(gnus-agentize)
@end lisp
@end itemize

That's it.  Gnus is now an ``offline'' newsreader.

Of course, to use it as such, you have to learn a few new commands.

@menu
* Agent Basics::           How it all is supposed to work.
* Agent Categories::       How to tell the Gnus Agent what to download.
* Agent Commands::         New commands for all the buffers.
* Agent Expiry::           How to make old articles go away.
* Agent and IMAP::         How to use the Agent with IMAP.
* Outgoing Messages::      What happens when you post/mail something?
* Agent Variables::        Customizing is fun.
* Example Setup::          An example @file{.gnus.el} file for offline people.
* Batching Agents::        How to fetch news from a @code{cron} job.
* Agent Caveats::          What you think it'll do and what it does.
@end menu


@node Agent Basics
@subsection Agent Basics

First, let's get some terminology out of the way.

The Gnus Agent is said to be @dfn{unplugged} when you have severed the
connection to the net (and notified the Agent that this is the case).
When the connection to the net is up again (and Gnus knows this), the
Agent is @dfn{plugged}.

The @dfn{local} machine is the one you're running on, and which isn't
connected to the net continuously.

@dfn{Downloading} means fetching things from the net to your local
machine.  @dfn{Uploading} is doing the opposite.

Let's take a typical Gnus session using the Agent.

@itemize @bullet

@item
You start Gnus with @code{gnus-unplugged}.  This brings up the Gnus
Agent in a disconnected state.  You can read all the news that you have
already fetched while in this mode.

@item
You then decide to see whether any new news has arrived.  You connect
your machine to the net (using PPP or whatever), and then hit @kbd{J j}
to make Gnus become @dfn{plugged} and use @kbd{g} to check for new mail
as usual.  To check for new mail in unplugged mode, see (@pxref{Mail
Source Specifiers}).

@item
You can then read the new news immediately, or you can download the news
onto your local machine.  If you want to do the latter, you press @kbd{g}
to check if there are any new news and then @kbd{J
s} to fetch all the eligible articles in all the groups.  (To let Gnus
know which articles you want to download, @pxref{Agent Categories}.)

@item
After fetching the articles, you press @kbd{J j} to make Gnus become
unplugged again, and you shut down the PPP thing (or whatever).  And
then you read the news offline.

@item
And then you go to step 2.
@end itemize

Here are some things you should do the first time (or so) that you use
the Agent.

@itemize @bullet

@item
Decide which servers should be covered by the Agent.  If you have a mail
backend, it would probably be nonsensical to have it covered by the
Agent.  Go to the server buffer (@kbd{^} in the group buffer) and press
@kbd{J a} the server (or servers) that you wish to have covered by the
Agent (@pxref{Server Agent Commands}).  This will typically be only the
primary select method, which is listed on the bottom in the buffer.

@item
Decide on download policy.  @xref{Agent Categories}.

@item
Uhm... that's it.
@end itemize


@node Agent Categories
@subsection Agent Categories

One of the main reasons to integrate the news transport layer into the
newsreader is to allow greater control over what articles to download.
There's not much point in downloading huge amounts of articles, just to
find out that you're not interested in reading any of them.  It's better
to be somewhat more conservative in choosing what to download, and then
mark the articles for downloading manually if it should turn out that
you're interested in the articles anyway.

The main way to control what is to be downloaded is to create a
@dfn{category} and then assign some (or all) groups to this category.
Groups that do not belong in any other category belong to the
@code{default} category.  Gnus has its own buffer for creating and
managing categories.

@menu
* Category Syntax::       What a category looks like.
* The Category Buffer::   A buffer for maintaining categories.
* Category Variables::    Customize'r'Us.
@end menu


@node Category Syntax
@subsubsection Category Syntax

A category consists of two things.

@enumerate
@item
A predicate which (generally) gives a rough outline of which articles
are eligible for downloading; and

@item
a score rule which (generally) gives you a finer granularity when
deciding what articles to download.  (Note that this @dfn{download
score} is not necessarily related to normal scores.)
@end enumerate

A predicate in its simplest form can be a single predicate such as
@code{true} or @code{false}.  These two will download every available
article or nothing respectively.  In the case of these two special
predicates an additional score rule is superfluous.

Predicates of @code{high} or @code{low} download articles in respect of
their scores in relationship to @code{gnus-agent-high-score} and
@code{gnus-agent-low-score} as described below.

To gain even finer control of what is to be regarded eligible for
download a predicate can consist of a number of predicates with logical
operators sprinkled in between.

Perhaps some examples are in order.

Here's a simple predicate.  (It's the default predicate, in fact, used
for all groups that don't belong to any other category.)

@lisp
short
@end lisp

Quite simple, eh?  This predicate is true if and only if the article is
short (for some value of ``short'').

Here's a more complex predicate:

@lisp
(or high
    (and
     (not low)
     (not long)))
@end lisp

This means that an article should be downloaded if it has a high score,
or if the score is not low and the article is not long.  You get the
drift.

The available logical operators are @code{or}, @code{and} and
@code{not}.  (If you prefer, you can use the more ``C''-ish operators
@samp{|}, @code{&} and @code{!} instead.)

The following predicates are pre-defined, but if none of these fit what
you want to do, you can write your own.

@table @code
@item short
True iff the article is shorter than @code{gnus-agent-short-article}
lines; default 100.

@item long
True iff the article is longer than @code{gnus-agent-long-article}
lines; default 200.

@item low
True iff the article has a download score less than
@code{gnus-agent-low-score}; default 0.

@item high
True iff the article has a download score greater than
@code{gnus-agent-high-score}; default 0.

@item spam
True iff the Gnus Agent guesses that the article is spam.  The
heuristics may change over time, but at present it just computes a
checksum and sees whether articles match.

@item true
Always true.

@item false
Always false.
@end table

If you want to create your own predicate function, here's what you have
to know:  The functions are called with no parameters, but the
@code{gnus-headers} and @code{gnus-score} dynamic variables are bound to
useful values.

For example, you could decide that you don't want to download articles
that were posted more than a certain number of days ago (e.g. posted
more than @code{gnus-agent-expire-days} ago) you might write a function
something along the lines of the following:

@lisp
(defun my-article-old-p ()
  "Say whether an article is old."
  (< (time-to-days (date-to-time (mail-header-date gnus-headers)))
     (- (time-to-days (current-time)) gnus-agent-expire-days)))
@end lisp

with the predicate then defined as:

@lisp
(not my-article-old-p)
@end lisp

or you could append your predicate to the predefined
@code{gnus-category-predicate-alist} in your @file{~/.gnus.el} or
wherever.  (Note: this would have to be at a point *after*
@code{gnus-agent} has been loaded via @code{(gnus-agentize)})

@lisp
(setq  gnus-category-predicate-alist
  (append gnus-category-predicate-alist
         '((old . my-article-old-p))))
@end lisp

and simply specify your predicate as:

@lisp
(not old)
@end lisp

If/when using something like the above, be aware that there are many
misconfigured systems/mailers out there and so an article's date is not
always a reliable indication of when it was posted.  Hell, some people
just don't give a damm.

The above predicates apply to *all* the groups which belong to the
category.  However, if you wish to have a specific predicate for an
individual group within a category, or you're just too lazy to set up a
new category, you can enter a group's individual predicate in it's group
parameters like so:

@lisp
(agent-predicate . short)
@end lisp

This is the group parameter equivalent of the agent category default.
Note that when specifying a single word predicate like this, the
@code{agent-predicate} specification must be in dotted pair notation.

The equivalent of the longer example from above would be:

@lisp
(agent-predicate or high (and (not low) (not long)))
@end lisp

The outer parenthesis required in the category specification are not
entered here as, not being in dotted pair notation, the value of the
predicate is assumed to be a list.


Now, the syntax of the download score is the same as the syntax of
normal score files, except that all elements that require actually
seeing the article itself are verboten.  This means that only the
following headers can be scored on: @code{Subject}, @code{From},
@code{Date}, @code{Message-ID}, @code{References}, @code{Chars},
@code{Lines}, and @code{Xref}.

As with predicates, the specification of the @code{download score rule}
to use in respect of a group can be in either the category definition if
it's to be applicable to all groups in therein, or a group's parameters
if it's to be specific to that group.

In both of these places the @code{download score rule} can take one of
three forms:

@enumerate
@item
Score rule

This has the same syntax as a normal gnus score file except only a
subset of scoring keywords are available as mentioned above.

example:

@itemize @bullet
@item
Category specification

@lisp
(("from"
       ("Lars Ingebrigtsen" 1000000 nil s))
("lines"
       (500 -100 nil <)))
@end lisp

@item
Group Parameter specification

@lisp
(agent-score ("from"
                   ("Lars Ingebrigtsen" 1000000 nil s))
             ("lines"
                   (500 -100 nil <)))
@end lisp

Again, note the omission of the outermost parenthesis here.
@end itemize

@item
Agent score file

These score files must *only* contain the permitted scoring keywords
stated above.

example:

@itemize @bullet
@item
Category specification

@lisp
("~/News/agent.SCORE")
@end lisp

or perhaps

@lisp
("~/News/agent.SCORE" "~/News/agent.group.SCORE")
@end lisp

@item
Group Parameter specification

@lisp
(agent-score "~/News/agent.SCORE")
@end lisp

Additional score files can be specified as above.  Need I say anything
about parenthesis?
@end itemize

@item
Use @code{normal} score files

If you dont want to maintain two sets of scoring rules for a group, and
your desired @code{downloading} criteria for a group are the same as your
@code{reading} criteria then you can tell the agent to refer to your
@code{normal} score files when deciding what to download.

These directives in either the category definition or a group's
parameters will cause the agent to read in all the applicable score
files for a group, *filtering out* those those sections that do not
relate to one of the permitted subset of scoring keywords.

@itemize @bullet
@item
Category Specification

@lisp
file
@end lisp

@item
Group Parameter specification

@lisp
(agent-score . file)
@end lisp
@end itemize
@end enumerate

@node The Category Buffer
@subsubsection The Category Buffer

You'd normally do all category maintenance from the category buffer.
When you enter it for the first time (with the @kbd{J c} command from
the group buffer), you'll only see the @code{default} category.

The following commands are available in this buffer:

@table @kbd
@item q
@kindex q (Category)
@findex gnus-category-exit
Return to the group buffer (@code{gnus-category-exit}).

@item k
@kindex k (Category)
@findex gnus-category-kill
Kill the current category (@code{gnus-category-kill}).

@item c
@kindex c (Category)
@findex gnus-category-copy
Copy the current category (@code{gnus-category-copy}).

@item a
@kindex a (Category)
@findex gnus-category-add
Add a new category (@code{gnus-category-add}).

@item p
@kindex p (Category)
@findex gnus-category-edit-predicate
Edit the predicate of the current category
(@code{gnus-category-edit-predicate}).

@item g
@kindex g (Category)
@findex gnus-category-edit-groups
Edit the list of groups belonging to the current category
(@code{gnus-category-edit-groups}).

@item s
@kindex s (Category)
@findex gnus-category-edit-score
Edit the download score rule of the current category
(@code{gnus-category-edit-score}).

@item l
@kindex l (Category)
@findex gnus-category-list
List all the categories (@code{gnus-category-list}).
@end table


@node Category Variables
@subsubsection Category Variables

@table @code
@item gnus-category-mode-hook
@vindex gnus-category-mode-hook
Hook run in category buffers.

@item gnus-category-line-format
@vindex gnus-category-line-format
Format of the lines in the category buffer (@pxref{Formatting
Variables}).  Valid elements are:

@table @samp
@item c
The name of the category.

@item g
The number of groups in the category.
@end table

@item gnus-category-mode-line-format
@vindex gnus-category-mode-line-format
Format of the category mode line (@pxref{Mode Line Formatting}).

@item gnus-agent-short-article
@vindex gnus-agent-short-article
Articles that have fewer lines than this are short.  Default 100.

@item gnus-agent-long-article
@vindex gnus-agent-long-article
Articles that have more lines than this are long.  Default 200.

@item gnus-agent-low-score
@vindex gnus-agent-low-score
Articles that have a score lower than this have a low score.  Default
0.

@item gnus-agent-high-score
@vindex gnus-agent-high-score
Articles that have a score higher than this have a high score.  Default
0.

@end table


@node Agent Commands
@subsection Agent Commands

All the Gnus Agent commands are on the @kbd{J} submap.  The @kbd{J j}
(@code{gnus-agent-toggle-plugged} command works in all modes, and
toggles the plugged/unplugged state of the Gnus Agent.


@menu
* Group Agent Commands::
* Summary Agent Commands::
* Server Agent Commands::
@end menu

You can run a complete batch fetch from the command line with the
following incantation:

@cindex gnus-agent-batch-fetch
@example
$ emacs -batch -l ~/.gnus.el -f gnus-agent-batch-fetch
@end example



@node Group Agent Commands
@subsubsection Group Agent Commands

@table @kbd
@item J u
@kindex J u (Agent Group)
@findex gnus-agent-fetch-groups
Fetch all eligible articles in the current group
(@code{gnus-agent-fetch-groups}).

@item J c
@kindex J c (Agent Group)
@findex gnus-enter-category-buffer
Enter the Agent category buffer (@code{gnus-enter-category-buffer}).

@item J s
@kindex J s (Agent Group)
@findex gnus-agent-fetch-session
Fetch all eligible articles in all groups
(@code{gnus-agent-fetch-session}).

@item J S
@kindex J S (Agent Group)
@findex gnus-group-send-drafts
Send all sendable messages in the draft group
(@code{gnus-group-send-drafts}).  @xref{Drafts}.

@item J a
@kindex J a (Agent Group)
@findex gnus-agent-add-group
Add the current group to an Agent category
(@code{gnus-agent-add-group}).  This command understands the
process/prefix convention (@pxref{Process/Prefix}).

@item J r
@kindex J r (Agent Group)
@findex gnus-agent-remove-group
Remove the current group from its category, if any
(@code{gnus-agent-remove-group}).  This command understands the
process/prefix convention (@pxref{Process/Prefix}).

@item J Y
@kindex J Y (Agent Group)
@findex gnus-agent-synchronize-flags
Synchronize flags changed while unplugged with remote server, if any.


@end table


@node Summary Agent Commands
@subsubsection Summary Agent Commands

@table @kbd
@item J #
@kindex J # (Agent Summary)
@findex gnus-agent-mark-article
Mark the article for downloading (@code{gnus-agent-mark-article}).

@item J M-#
@kindex J M-# (Agent Summary)
@findex gnus-agent-unmark-article
Remove the downloading mark from the article
(@code{gnus-agent-unmark-article}).

@item @@
@kindex @@ (Agent Summary)
@findex gnus-agent-toggle-mark
Toggle whether to download the article (@code{gnus-agent-toggle-mark}).

@item J c
@kindex J c (Agent Summary)
@findex gnus-agent-catchup
Mark all undownloaded articles as read (@code{gnus-agent-catchup}).

@end table


@node Server Agent Commands
@subsubsection Server Agent Commands

@table @kbd
@item J a
@kindex J a (Agent Server)
@findex gnus-agent-add-server
Add the current server to the list of servers covered by the Gnus Agent
(@code{gnus-agent-add-server}).

@item J r
@kindex J r (Agent Server)
@findex gnus-agent-remove-server
Remove the current server from the list of servers covered by the Gnus
Agent (@code{gnus-agent-remove-server}).

@end table


@node Agent Expiry
@subsection Agent Expiry

@vindex gnus-agent-expire-days
@findex gnus-agent-expire
@kindex M-x gnus-agent-expire
@cindex Agent expiry
@cindex Gnus Agent expiry
@cindex expiry

@code{nnagent} doesn't handle expiry.  Instead, there's a special
@code{gnus-agent-expire} command that will expire all read articles that
are older than @code{gnus-agent-expire-days} days.  It can be run
whenever you feel that you're running out of space.  It's not
particularly fast or efficient, and it's not a particularly good idea to
interrupt it (with @kbd{C-g} or anything else) once you've started it.

@vindex gnus-agent-expire-all
if @code{gnus-agent-expire-all} is non-@code{nil}, this command will
expire all articles---unread, read, ticked and dormant.  If @code{nil}
(which is the default), only read articles are eligible for expiry, and
unread, ticked and dormant articles will be kept indefinitely.


@node Agent and IMAP
@subsection Agent and IMAP

The Agent work with any Gnus backend, including nnimap.  However, since
there are some conceptual differences between NNTP and IMAP, this
section (should) provide you with some information to make Gnus Agent
work smoother as a IMAP Disconnected Mode client.

The first thing to keep in mind is that all flags (read, ticked, etc)
are kept on the IMAP server, rather than in @code{.newsrc} as is the
case for nntp.  Thus Gnus need to remember flag changes when
disconnected, and synchronize these flags when you plug back in.

Gnus keep track of flag changes when reading nnimap groups under the
Agent by default.  When you plug back in, by default Gnus will check if
you have any changed any flags and ask if you wish to synchronize theese
with the server.  This behaviour is customizable with
@code{gnus-agent-synchronize-flags}.

@vindex gnus-agent-synchronize-flags
If @code{gnus-agent-synchronize-flags} is @code{nil}, the Agent will
never automatically synchronize flags.  If it is @code{ask}, the
default, the Agent will check if you made any changes and if so ask if
you wish to synchronize these when you re-connect.  If it has any other
value, all flags will be synchronized automatically.

If you do not wish to automatically synchronize flags when you
re-connect, this can be done manually with the
@code{gnus-agent-synchronize-flags} command that is bound to @kbd{J Y}
in the group buffer by default.

Some things are currently not implemented in the Agent that you'd might
expect from a disconnected IMAP client, including:

@itemize @bullet

@item
Copying/moving articles into nnimap groups when unplugged.

@item
Creating/deleting nnimap groups when unplugged.

@end itemize

Technical note: the synchronization algorithm does not work by "pushing"
all local flags to the server, but rather incrementally update the
server view of flags by changing only those flags that were changed by
the user.  Thus, if you set one flag on a article, quit the group and
re-select the group and remove the flag; the flag will be set and
removed from the server when you "synchronize".  The queued flag
operations can be found in the per-server @code{flags} file in the Agent
directory.  It's emptied when you synchronize flags.


@node Outgoing Messages
@subsection Outgoing Messages

When Gnus is unplugged, all outgoing messages (both mail and news) are
stored in the draft groups (@pxref{Drafts}).  You can view them there
after posting, and edit them at will.

When Gnus is plugged again, you can send the messages either from the
draft group with the special commands available there, or you can use
the @kbd{J S} command in the group buffer to send all the sendable
messages in the draft group.



@node Agent Variables
@subsection Agent Variables

@table @code
@item gnus-agent-directory
@vindex gnus-agent-directory
Where the Gnus Agent will store its files.  The default is
@file{~/News/agent/}.

@item gnus-agent-handle-level
@vindex gnus-agent-handle-level
Groups on levels (@pxref{Group Levels}) higher than this variable will
be ignored by the Agent.  The default is @code{gnus-level-subscribed},
which means that only subscribed group will be considered by the Agent
by default.

@item gnus-agent-plugged-hook
@vindex gnus-agent-plugged-hook
Hook run when connecting to the network.

@item gnus-agent-unplugged-hook
@vindex gnus-agent-unplugged-hook
Hook run when disconnecting from the network.

@end table


@node Example Setup
@subsection Example Setup

If you don't want to read this manual, and you have a fairly standard
setup, you may be able to use something like the following as your
@file{.gnus.el} file to get started.

@lisp
;;; Define how Gnus is to fetch news.  We do this over @sc{nntp}
;;; from your ISP's server.
(setq gnus-select-method '(nntp "news.your-isp.com"))

;;; Define how Gnus is to read your mail.  We read mail from
;;; your ISP's POP server.
(setq mail-sources '((pop :server "pop.your-isp.com")))

;;; Say how Gnus is to store the mail.  We use nnml groups.
(setq gnus-secondary-select-methods '((nnml "")))

;;; Make Gnus into an offline newsreader.
(gnus-agentize)
@end lisp

That should be it, basically.  Put that in your @file{~/.gnus.el} file,
edit to suit your needs, start up PPP (or whatever), and type @kbd{M-x
gnus}.

If this is the first time you've run Gnus, you will be subscribed
automatically to a few default newsgroups.  You'll probably want to
subscribe to more groups, and to do that, you have to query the
@sc{nntp} server for a complete list of groups with the @kbd{A A}
command.  This usually takes quite a while, but you only have to do it
once.

After reading and parsing a while, you'll be presented with a list of
groups.  Subscribe to the ones you want to read with the @kbd{u}
command.  @kbd{l} to make all the killed groups disappear after you've
subscribe to all the groups you want to read.  (@kbd{A k} will bring
back all the killed groups.)

You can now read the groups at once, or you can download the articles
with the @kbd{J s} command.  And then read the rest of this manual to
find out which of the other gazillion things you want to customize.


@node Batching Agents
@subsection Batching Agents

Having the Gnus Agent fetch articles (and post whatever messages you've
written) is quite easy once you've gotten things set up properly.  The
following shell script will do everything that is necessary:

@example
#!/bin/sh
emacs -batch -l ~/.emacs -f gnus-agent-batch >/dev/null
@end example


@node Agent Caveats
@subsection Agent Caveats

The Gnus Agent doesn't seem to work like most other offline
newsreaders.  Here are some common questions that some imaginary people
may ask:

@table @dfn
@item If I read an article while plugged, do they get entered into the
Agent?

@strong{No.}

@item If I read an article while plugged, and the article already exists
in the Agent, will it get downloaded once more?

@strong{Yes.}

@end table

In short, when Gnus is unplugged, it only looks into the locally stored
articles; when it's plugged, it only talks to your ISP.


@node Scoring
@chapter Scoring
@cindex scoring

Other people use @dfn{kill files}, but we here at Gnus Towers like
scoring better than killing, so we'd rather switch than fight.  They do
something completely different as well, so sit up straight and pay
attention!

@vindex gnus-summary-mark-below
All articles have a default score (@code{gnus-summary-default-score}),
which is 0 by default.  This score may be raised or lowered either
interactively or by score files.  Articles that have a score lower than
@code{gnus-summary-mark-below} are marked as read.

Gnus will read any @dfn{score files} that apply to the current group
before generating the summary buffer.

There are several commands in the summary buffer that insert score
entries based on the current article.  You can, for instance, ask Gnus to
lower or increase the score of all articles with a certain subject.

There are two sorts of scoring entries: Permanent and temporary.
Temporary score entries are self-expiring entries.  Any entries that are
temporary and have not been used for, say, a week, will be removed
silently to help keep the sizes of the score files down.

@menu
* Summary Score Commands::   Adding score entries for the current group.
* Group Score Commands::     General score commands.
* Score Variables::          Customize your scoring.  (My, what terminology).
* Score File Format::        What a score file may contain.
* Score File Editing::       You can edit score files by hand as well.
* Adaptive Scoring::         Big Sister Gnus knows what you read.
* Home Score File::          How to say where new score entries are to go.
* Followups To Yourself::    Having Gnus notice when people answer you.
* Scoring Tips::             How to score effectively.
* Reverse Scoring::          That problem child of old is not problem.
* Global Score Files::       Earth-spanning, ear-splitting score files.
* Kill Files::               They are still here, but they can be ignored.
* Converting Kill Files::    Translating kill files to score files.
* GroupLens::                Getting predictions on what you like to read.
* Advanced Scoring::         Using logical expressions to build score rules.
* Score Decays::             It can be useful to let scores wither away.
@end menu


@node Summary Score Commands
@section Summary Score Commands
@cindex score commands

The score commands that alter score entries do not actually modify real
score files.  That would be too inefficient.  Gnus maintains a cache of
previously loaded score files, one of which is considered the
@dfn{current score file alist}.  The score commands simply insert
entries into this list, and upon group exit, this list is saved.

The current score file is by default the group's local score file, even
if no such score file actually exists.  To insert score commands into
some other score file (e.g. @file{all.SCORE}), you must first make this
score file the current one.

General score commands that don't actually change the score file:

@table @kbd

@item V s
@kindex V s (Summary)
@findex gnus-summary-set-score
Set the score of the current article (@code{gnus-summary-set-score}).

@item V S
@kindex V S (Summary)
@findex gnus-summary-current-score
Display the score of the current article
(@code{gnus-summary-current-score}).

@item V t
@kindex V t (Summary)
@findex gnus-score-find-trace
Display all score rules that have been used on the current article
(@code{gnus-score-find-trace}).

@item V R
@kindex V R (Summary)
@findex gnus-summary-rescore
Run the current summary through the scoring process
(@code{gnus-summary-rescore}).  This might be useful if you're playing
around with your score files behind Gnus' back and want to see the
effect you're having.

@item V c
@kindex V c (Summary)
@findex gnus-score-change-score-file
Make a different score file the current
(@code{gnus-score-change-score-file}).

@item V e
@kindex V e (Summary)
@findex gnus-score-edit-current-scores
Edit the current score file (@code{gnus-score-edit-current-scores}).
You will be popped into a @code{gnus-score-mode} buffer (@pxref{Score
File Editing}).

@item V f
@kindex V f (Summary)
@findex gnus-score-edit-file
Edit a score file and make this score file the current one
(@code{gnus-score-edit-file}).

@item V F
@kindex V F (Summary)
@findex gnus-score-flush-cache
Flush the score cache (@code{gnus-score-flush-cache}).  This is useful
after editing score files.

@item V C
@kindex V C (Summary)
@findex gnus-score-customize
Customize a score file in a visually pleasing manner
(@code{gnus-score-customize}).

@end table

The rest of these commands modify the local score file.

@table @kbd

@item V m
@kindex V m (Summary)
@findex gnus-score-set-mark-below
Prompt for a score, and mark all articles with a score below this as
read (@code{gnus-score-set-mark-below}).

@item V x
@kindex V x (Summary)
@findex gnus-score-set-expunge-below
Prompt for a score, and add a score rule to the current score file to
expunge all articles below this score
(@code{gnus-score-set-expunge-below}).
@end table

The keystrokes for actually making score entries follow a very regular
pattern, so there's no need to list all the commands.  (Hundreds of
them.)

@findex gnus-summary-increase-score
@findex gnus-summary-lower-score

@enumerate
@item
The first key is either @kbd{I} (upper case i) for increasing the score
or @kbd{L} for lowering the score.
@item
The second key says what header you want to score on.  The following
keys are available:
@table @kbd

@item a
Score on the author name.

@item s
Score on the subject line.

@item x
Score on the @code{Xref} line---i.e., the cross-posting line.

@item r
Score on the @code{References} line.

@item d
Score on the date.

@item l
Score on the number of lines.

@item i
Score on the @code{Message-ID} header.

@item f
Score on followups---this matches the author name, and adds scores to
the followups to this author.

@item b
Score on the body.

@item h
Score on the head.

@item t
Score on thread.

@end table

@item
The third key is the match type.  Which match types are valid depends on
what headers you are scoring on.

@table @code

@item strings

@table @kbd

@item e
Exact matching.

@item s
Substring matching.

@item f
Fuzzy matching (@pxref{Fuzzy Matching}).

@item r
Regexp matching
@end table

@item date
@table @kbd

@item b
Before date.

@item a
After date.

@item n
This date.
@end table

@item number
@table @kbd

@item <
Less than number.

@item =
Equal to number.

@item >
Greater than number.
@end table
@end table

@item
The fourth and final key says whether this is a temporary (i.e., expiring)
score entry, or a permanent (i.e., non-expiring) score entry, or whether
it is to be done immediately, without adding to the score file.
@table @kbd

@item t
Temporary score entry.

@item p
Permanent score entry.

@item i
Immediately scoring.
@end table

@end enumerate

So, let's say you want to increase the score on the current author with
exact matching permanently: @kbd{I a e p}.  If you want to lower the
score based on the subject line, using substring matching, and make a
temporary score entry: @kbd{L s s t}.  Pretty easy.

To make things a bit more complicated, there are shortcuts.  If you use
a capital letter on either the second or third keys, Gnus will use
defaults for the remaining one or two keystrokes.  The defaults are
``substring'' and ``temporary''.  So @kbd{I A} is the same as @kbd{I a s
t}, and @kbd{I a R} is the same as @kbd{I a r t}.

These functions take both the numerical prefix and the symbolic prefix
(@pxref{Symbolic Prefixes}).  A numerical prefix says how much to lower
(or increase) the score of the article.  A symbolic prefix of @code{a}
says to use the @file{all.SCORE} file for the command instead of the
current score file.

@vindex gnus-score-mimic-keymap
The @code{gnus-score-mimic-keymap} says whether these commands will
pretend they are keymaps or not.


@node Group Score Commands
@section Group Score Commands
@cindex group score commands

There aren't many of these as yet, I'm afraid.

@table @kbd

@item W f