This is Info file ../info/emacs, produced by Makeinfo version 1.68 from
the input file emacs.texi.

   This is the thirteenth edition of the `GNU Emacs Manual', updated
for Emacs version 20.3

INFO-DIR-SECTION Editors
START-INFO-DIR-ENTRY
* Emacs: (emacs).	The extensible self-documenting text editor.
END-INFO-DIR-ENTRY

   Published by the Free Software Foundation 59 Temple Place, Suite 330
Boston, MA  02111-1307 USA

   Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1996, 1997, 1998
Free Software Foundation, Inc.

   Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

   Permission is granted to copy and distribute modified versions of
this manual under the conditions for verbatim copying, provided also
that the sections entitled "The GNU Manifesto", "Distribution" and "GNU
General Public License" are included exactly as in the original, and
provided that the entire resulting derived work is distributed under the
terms of a permission notice identical to this one.

   Permission is granted to copy and distribute translations of this
manual into another language, under the above conditions for modified
versions, except that the sections entitled "The GNU Manifesto",
"Distribution" and "GNU General Public License" may be included in a
translation approved by the Free Software Foundation instead of in the
original English.


File: emacs,  Node: Gnus Startup,  Next: Summary of Gnus,  Prev: Buffers of Gnus,  Up: Gnus

When Gnus Starts Up
-------------------

   At startup, Gnus reads your `.newsrc' news initialization file and
attempts to communicate with the local news server, which is a
repository of news articles.  The news server need not be the same
computer you are logged in on.

   If you start Gnus and connect to the server, but do not see any
newsgroups listed in the group buffer, type `L' or `A k' to get a
listing of all the groups.  Then type `u' to toggle subscription to
groups.

   The first time you start Gnus, Gnus subscribes you to a few selected
groups.  All other groups start out as "killed groups" for you; you can
list them with `A k'.  All new groups that subsequently come to exist
at the news server become "zombie groups" for you; type `A z' to list
them.  You can subscribe to a group shown in these lists using the `u'
command.

   When you quit Gnus with `q', it automatically records in your
`.newsrc' and `.newsrc.eld' initialization files the subscribed or
unsubscribed status of all groups.  You should normally not edit these
files manually, but you may if you know how.


File: emacs,  Node: Summary of Gnus,  Prev: Gnus Startup,  Up: Gnus

Summary of Gnus Commands
------------------------

   Reading news is a two step process:

  1. Choose a group in the group buffer.

  2. Select articles from the summary buffer.  Each article selected is
     displayed in the article buffer in a large window, below the
     summary buffer in its small window.

   Each Gnus buffer has its own special commands; however, the meanings
of any given key in the various Gnus buffers are usually analogous, even
if not identical.  Here are commands for the group and summary buffers:

`q'
     In the group buffer, update your `.newsrc' initialization file and
     quit Gnus.

     In the summary buffer, exit the current group and return to the
     group buffer.  Thus, typing `q' twice quits Gnus.

`L'
     In the group buffer, list all the groups available on your news
     server (except those you have killed).  This may be a long list!

`l'
     In the group buffer, list only the groups to which you subscribe
     and which contain unread articles.

`u'
     In the group buffer, unsubscribe from (or subscribe to) the group
     listed in the line that point is on.  When you quit Gnus by typing
     `q', Gnus lists in your `.newsrc' file which groups you have
     subscribed to.  The next time you start Gnus, you won't see this
     group, because Gnus normally displays only subscribed-to groups.

`C-k'
     In the group buffer, "kill" the current line's group--don't even
     list it in `.newsrc' from now on.  This affects future Gnus
     sessions as well as the present session.

     When you quit Gnus by typing `q', Gnus writes information in the
     file `.newsrc' describing all newsgroups except those you have
     "killed."

`<SPC>'
     In the group buffer, select the group on the line under the cursor
     and display the first unread article in that group.

     In the summary buffer,

        * Select the article on the line under the cursor if none is
          selected.

        * Scroll the text of the selected article (if there is one).

        * Select the next unread article if at the end of the current
          article.

     Thus, you can move through all the articles by repeatedly typing
     <SPC>.

`<DEL>'
     In the group buffer, move point to the previous group containing
     unread articles.

     In the summary buffer, scroll the text of the article backwards.

`n'
     Move point to the next unread group, or select the next unread
     article.

`p'
     Move point to the previous unread group, or select the previous
     unread article.

`C-n'
`C-p'
     Move point to the next or previous item, even if it is marked as
     read.  This does not select the article or group on that line.

`s'
     In the summary buffer, do an incremental search of the current
     text in the article buffer, just as if you switched to the article
     buffer and typed `C-s'.

`M-s REGEXP <RET>'
     In the summary buffer, search forward for articles containing a
     match for REGEXP.


File: emacs,  Node: Shell,  Next: Emacs Server,  Prev: Gnus,  Up: Top

Running Shell Commands from Emacs
=================================

   Emacs has commands for passing single command lines to inferior shell
processes; it can also run a shell interactively with input and output
to an Emacs buffer named `*shell*'.

`M-! CMD <RET>'
     Run the shell command line CMD and display the output
     (`shell-command').

`M-| CMD <RET>'
     Run the shell command line CMD with region contents as input;
     optionally replace the region with the output
     (`shell-command-on-region').

`M-x shell'
     Run a subshell with input and output through an Emacs buffer.  You
     can then give commands interactively.

* Menu:

* Single Shell::           How to run one shell command and return.
* Interactive Shell::      Permanent shell taking input via Emacs.
* Shell Mode::             Special Emacs commands used with permanent shell.
* History: Shell History.  Repeating previous commands in a shell buffer.
* Options: Shell Options.  Options for customizing Shell mode.
* Remote Host::            Connecting to another computer.


File: emacs,  Node: Single Shell,  Next: Interactive Shell,  Up: Shell

Single Shell Commands
---------------------

   `M-!' (`shell-command') reads a line of text using the minibuffer
and executes it as a shell command in a subshell made just for that
command.  Standard input for the command comes from the null device.
If the shell command produces any output, the output goes into an Emacs
buffer named `*Shell Command Output*', which is displayed in another
window but not selected.  A numeric argument, as in `M-1 M-!', directs
this command to insert any output into the current buffer.  In that
case, point is left before the output and the mark is set after the
output.

   If the shell command line ends in `&', it runs asynchronously.

   `M-|' (`shell-command-on-region') is like `M-!' but passes the
contents of the region as the standard input to the shell command,
instead of no input.  If a numeric argument is used, meaning insert the
output in the current buffer, then the old region is deleted first and
the output replaces it as the contents of the region.

   Both `M-!' and `M-|' use `shell-file-name' to specify the shell to
use.  This variable is initialized based on your `SHELL' environment
variable when Emacs is started.  If the file name does not specify a
directory, the directories in the list `exec-path' are searched; this
list is initialized based on the environment variable `PATH' when Emacs
is started.  Your `.emacs' file can override either or both of these
default initializations.

   Both `M-!' and `M-|' wait for the shell command to complete.  To
stop waiting, type `C-g' to quit; that terminates the shell command
with the signal `SIGINT'--the same signal that `C-c' normally generates
in the shell.  Emacs waits until the command actually terminates.  If
the shell command doesn't stop (because it ignores the `SIGINT'
signal), type `C-g' again; this sends the command a `SIGKILL' signal
which is impossible to ignore.

   To specify a coding system for `M-!' or `M-|', use the command `C-x
<RET> c' immediately beforehand.  *Note Specify Coding::.


File: emacs,  Node: Interactive Shell,  Next: Shell Mode,  Prev: Single Shell,  Up: Shell

Interactive Inferior Shell
--------------------------

   To run a subshell interactively, putting its typescript in an Emacs
buffer, use `M-x shell'.  This creates (or reuses) a buffer named
`*shell*' and runs a subshell with input coming from and output going
to that buffer.  That is to say, any "terminal output" from the subshell
goes into the buffer, advancing point, and any "terminal input" for the
subshell comes from text in the buffer.  To give input to the subshell,
go to the end of the buffer and type the input, terminated by <RET>.

   Emacs does not wait for the subshell to do anything.  You can switch
windows or buffers and edit them while the shell is waiting, or while
it is running a command.  Output from the subshell waits until Emacs
has time to process it; this happens whenever Emacs is waiting for
keyboard input or for time to elapse.

   To make multiple subshells, rename the buffer `*shell*' to something
different using `M-x rename-uniquely'.  Then type `M-x shell' again to
create a new buffer `*shell*' with its own subshell.  If you rename
this buffer as well, you can create a third one, and so on.  All the
subshells run independently and in parallel.

   The file name used to load the subshell is the value of the variable
`explicit-shell-file-name', if that is non-`nil'.  Otherwise, the
environment variable `ESHELL' is used, or the environment variable
`SHELL' if there is no `ESHELL'.  If the file name specified is
relative, the directories in the list `exec-path' are searched; this
list is initialized based on the environment variable `PATH' when Emacs
is started.  Your `.emacs' file can override either or both of these
default initializations.

   To specify a coding system for the shell, you can use the command
`C-x <RET> c' immediately before `M-x shell'.  You can also specify a
coding system after starting the shell by using `C-x <RET> p' in the
shell buffer.  *Note Specify Coding::.

   As soon as the subshell is started, it is sent as input the contents
of the file `~/.emacs_SHELLNAME', if that file exists, where SHELLNAME
is the name of the file that the shell was loaded from.  For example,
if you use bash, the file sent to it is `~/.emacs_bash'.

   `cd', `pushd' and `popd' commands given to the inferior shell are
watched by Emacs so it can keep the `*shell*' buffer's default
directory the same as the shell's working directory.  These commands
are recognized syntactically by examining lines of input that are sent.
If you use aliases for these commands, you can tell Emacs to recognize
them also.  For example, if the value of the variable
`shell-pushd-regexp' matches the beginning of a shell command line,
that line is regarded as a `pushd' command.  Change this variable when
you add aliases for `pushd'.  Likewise, `shell-popd-regexp' and
`shell-cd-regexp' are used to recognize commands with the meaning of
`popd' and `cd'.  These commands are recognized only at the beginning
of a shell command line.

   If Emacs gets an error while trying to handle what it believes is a
`cd', `pushd' or `popd' command, it runs the hook
`shell-set-directory-error-hook' (*note Hooks::.).

   If Emacs does not properly track changes in the current directory of
the subshell, use the command `M-x dirs' to ask the shell what its
current directory is.  This command works for shells that support the
most common command syntax; it may not work for unusual shells.

   You can also use `M-x dirtrack-mode' to enable (or disable) an
alternative and more aggressive method of tracking changes in the
current directory.

   Emacs defines the environment variable `EMACS' in the subshell, with
value `t'.  A shell script can check this variable to determine whether
it has been run from an Emacs subshell.


File: emacs,  Node: Shell Mode,  Next: Shell History,  Prev: Interactive Shell,  Up: Shell

Shell Mode
----------

   Shell buffers use Shell mode, which defines several special keys
attached to the `C-c' prefix.  They are chosen to resemble the usual
editing and job control characters present in shells that are not under
Emacs, except that you must type `C-c' first.  Here is a complete list
of the special key bindings of Shell mode:

`<RET>'
     At end of buffer send line as input; otherwise, copy current line
     to end of buffer and send it (`comint-send-input').  When a line is
     copied, any text at the beginning of the line that matches the
     variable `shell-prompt-pattern' is left out; this variable's value
     should be a regexp string that matches the prompts that your shell
     uses.

`<TAB>'
     Complete the command name or file name before point in the shell
     buffer (`comint-dynamic-complete').  <TAB> also completes history
     references (*note History References::.) and environment variable
     names.

     The variable `shell-completion-fignore' specifies a list of file
     name extensions to ignore in Shell mode completion.  The default
     setting ignores file names ending in `~', `#' or `%'.  Other
     related Comint modes use the variable `comint-completion-fignore'
     instead.

`M-?'
     Display temporarily a list of the possible completions of the file
     name before point in the shell buffer
     (`comint-dynamic-list-filename-completions').

`C-d'
     Either delete a character or send EOF
     (`comint-delchar-or-maybe-eof').  Typed at the end of the shell
     buffer, `C-d' sends EOF to the subshell.  Typed at any other
     position in the buffer, `C-d' deletes a character as usual.

`C-c C-a'
     Move to the beginning of the line, but after the prompt if any
     (`comint-bol').  If you repeat this command twice in a row, the
     second time it moves back to the process mark, which is the
     beginning of the input that you have not yet sent to the subshell.
     (Normally that is the same place--the end of the prompt on this
     line--but after `C-c <SPC>' the process mark may be in a previous
     line.)

`C-c <SPC>'
     Accumulate multiple lines of input, then send them together.  This
     command inserts a newline before point, but does not send the
     preceding text as input to the subshell-at least, not yet.  Both
     lines, the one before this newline and the one after, will be sent
     together (along with the newline that separates them), when you
     type <RET>.

`C-c C-u'
     Kill all text pending at end of buffer to be sent as input
     (`comint-kill-input').

`C-c C-w'
     Kill a word before point (`backward-kill-word').

`C-c C-c'
     Interrupt the shell or its current subjob if any
     (`comint-interrupt-subjob').  This command also kills any shell
     input pending in the shell buffer and not yet sent.

`C-c C-z'
     Stop the shell or its current subjob if any (`comint-stop-subjob').
     This command also kills any shell input pending in the shell
     buffer and not yet sent.

`C-c C-\'
     Send quit signal to the shell or its current subjob if any
     (`comint-quit-subjob').  This command also kills any shell input
     pending in the shell buffer and not yet sent.

`C-c C-o'
     Kill the last batch of output from a shell command
     (`comint-kill-output').  This is useful if a shell command spews
     out lots of output that just gets in the way.

`C-c C-r'
`C-M-l'
     Scroll to display the beginning of the last batch of output at the
     top of the window; also move the cursor there
     (`comint-show-output').

`C-c C-e'
     Scroll to put the end of the buffer at the bottom of the window
     (`comint-show-maximum-output').

`C-c C-f'
     Move forward across one shell command, but not beyond the current
     line (`shell-forward-command').  The variable
     `shell-command-regexp' specifies how to recognize the end of a
     command.

`C-c C-b'
     Move backward across one shell command, but not beyond the current
     line (`shell-backward-command').

`C-c C-l'
     Display the buffer's history of shell commands in another window
     (`comint-dynamic-list-input-ring').

`M-x dirs'
     Ask the shell what its current directory is, so that Emacs can
     agree with the shell.

`M-x send-invisible <RET> TEXT <RET>'
     Send TEXT as input to the shell, after reading it without echoing.
     This is useful when a shell command runs a program that asks for
     a password.

     Alternatively, you can arrange for Emacs to notice password prompts
     and turn off echoing for them, as follows:

          (add-hook 'comint-output-filter-functions
                    'comint-watch-for-password-prompt)

`M-x comint-continue-subjob'
     Continue the shell process.  This is useful if you accidentally
     suspend the shell process.(1)

`M-x comint-strip-ctrl-m'
     Discard all control-M characters from the current group of shell
     output.  The most convenient way to use this command is to make it
     run automatically when you get output from the subshell.  To do
     that, evaluate this Lisp expression:

          (add-hook 'comint-output-filter-functions
                    'comint-strip-ctrl-m)

`M-x comint-truncate-buffer'
     This command truncates the shell buffer to a certain maximum
     number of lines, specified by the variable
     `comint-buffer-maximum-size'.  Here's how to do this automatically
     each time you get output from the subshell:

          (add-hook 'comint-output-filter-functions
                    'comint-truncate-buffer)

   Shell mode also customizes the paragraph commands so that only shell
prompts start new paragraphs.  Thus, a paragraph consists of an input
command plus the output that follows it in the buffer.

   Shell mode is a derivative of Comint mode, a general-purpose mode for
communicating with interactive subprocesses.  Most of the features of
Shell mode actually come from Comint mode, as you can see from the
command names listed above.  The special features of Shell mode in
particular include the choice of regular expression for detecting
prompts, the directory tracking feature, and a few user commands.

   Other Emacs features that use variants of Comint mode include GUD
(*note Debuggers::.) and `M-x run-lisp' (*note External Lisp::.).

   You can use `M-x comint-run' to execute any program of your choice
in a subprocess using unmodified Comint mode--without the
specializations of Shell mode.

   ---------- Footnotes ----------

   (1) You should not suspend the shell process.  Suspending a subjob
of the shell is a completely different matter--that is normal practice,
but you must use the shell to continue the subjob; this command won't
do it.


File: emacs,  Node: Shell History,  Next: Shell Options,  Prev: Shell Mode,  Up: Shell

Shell Command History
---------------------

   Shell buffers support three ways of repeating earlier commands.  You
can use the same keys used in the minibuffer; these work much as they do
in the minibuffer, inserting text from prior commands while point
remains always at the end of the buffer.  You can move through the
buffer to previous inputs in their original place, then resubmit them or
copy them to the end.  Or you can use a `!'-style history reference.

* Menu:

* Ring: Shell Ring.             Fetching commands from the history list.
* Copy: Shell History Copying.  Moving to a command and then copying it.
* History References::          Expanding `!'-style history references.


File: emacs,  Node: Shell Ring,  Next: Shell History Copying,  Up: Shell History

Shell History Ring
..................

`M-p'
     Fetch the next earlier old shell command.

`M-n'
     Fetch the next later old shell command.

`M-r REGEXP <RET>'
`M-s REGEXP <RET>'
     Search backwards or forwards for old shell commands that match
     REGEXP.

`C-c C-x (Shell mode)'
     Fetch the next subsequent command from the history.

   Shell buffers provide a history of previously entered shell
commands.  To reuse shell commands from the history, use the editing
commands `M-p', `M-n', `M-r' and `M-s'.  These work just like the
minibuffer history commands except that they operate on the text at the
end of the shell buffer, where you would normally insert text to send
to the shell.

   `M-p' fetches an earlier shell command to the end of the shell
buffer.  Successive use of `M-p' fetches successively earlier shell
commands, each replacing any text that was already present as potential
shell input.  `M-n' does likewise except that it finds successively
more recent shell commands from the buffer.

   The history search commands `M-r' and `M-s' read a regular
expression and search through the history for a matching command.  Aside
from the choice of which command to fetch, they work just like `M-p'
and `M-r'.  If you enter an empty regexp, these commands reuse the same
regexp used last time.

   When you find the previous input you want, you can resubmit it by
typing <RET>, or you can edit it first and then resubmit it if you wish.

   Often it is useful to reexecute several successive shell commands
that were previously executed in sequence.  To do this, first find and
reexecute the first command of the sequence.  Then type `C-c C-x'; that
will fetch the following command--the one that follows the command you
just repeated.  Then type <RET> to reexecute this command.  You can
reexecute several successive commands by typing `C-c C-x <RET>' over
and over.

   These commands get the text of previous shell commands from a special
history list, not from the shell buffer itself.  Thus, editing the shell
buffer, or even killing large parts of it, does not affect the history
that these commands access.

   Some shells store their command histories in files so that you can
refer to previous commands from previous shell sessions.  Emacs reads
the command history file for your chosen shell, to initialize its own
command history.  The file name is `~/.bash_history' for bash,
`~/.sh_history' for ksh, and `~/.history' for other shells.


File: emacs,  Node: Shell History Copying,  Next: History References,  Prev: Shell Ring,  Up: Shell History

Shell History Copying
.....................

`C-c C-p'
     Move point to the previous prompt (`comint-previous-prompt').

`C-c C-n'
     Move point to the following prompt (`comint-next-prompt').

`C-c <RET>'
     Copy the input command which point is in, inserting the copy at
     the end of the buffer (`comint-copy-old-input').  This is useful
     if you move point back to a previous command.  After you copy the
     command, you can submit the copy as input with <RET>.  If you
     wish, you can edit the copy before resubmitting it.

   Moving to a previous input and then copying it with `C-c <RET>'
produces the same results--the same buffer contents--that you would get
by using `M-p' enough times to fetch that previous input from the
history list.  However, `C-c <RET>' copies the text from the buffer,
which can be different from what is in the history list if you edit the
input text in the buffer after it has been sent.


File: emacs,  Node: History References,  Prev: Shell History Copying,  Up: Shell History

Shell History References
........................

   Various shells including csh and bash support "history references"
that begin with `!' and `^'.  Shell mode can understand these
constructs and perform the history substitution for you.  If you insert
a history reference and type <TAB>, this searches the input history for
a matching command, performs substitution if necessary, and places the
result in the buffer in place of the history reference.  For example,
you can fetch the most recent command beginning with `mv' with `! m v
<TAB>'.  You can edit the command if you wish, and then resubmit the
command to the shell by typing <RET>.

   History references take effect only following a shell prompt.  The
variable `shell-prompt-pattern' specifies how to recognize a shell
prompt.  Comint modes in general use the variable
`comint-prompt-regexp' to specify how to find a prompt; Shell mode uses
`shell-prompt-pattern' to set up the local value of
`comint-prompt-regexp'.

   Shell mode can optionally expand history references in the buffer
when you send them to the shell.  To request this, set the variable
`comint-input-autoexpand' to `input'.

   You can make <SPC> perform history expansion by binding <SPC> to the
command `comint-magic-space'.


File: emacs,  Node: Shell Options,  Next: Remote Host,  Prev: Shell History,  Up: Shell

Shell Mode Options
------------------

   If the variable `comint-scroll-to-bottom-on-input' is non-`nil',
insertion and yank commands scroll the selected window to the bottom
before inserting.

   If `comint-scroll-show-maximum-output' is non-`nil', then scrolling
due to arrival of output tries to place the last line of text at the
bottom line of the window, so as to show as much useful text as
possible.  (This mimics the scrolling behavior of many terminals.)  The
default is `nil'.

   By setting `comint-scroll-to-bottom-on-output', you can opt for
having point jump to the end of the buffer whenever output arrives--no
matter where in the buffer point was before.  If the value is `this',
point jumps in the selected window.  If the value is `all', point jumps
in each window that shows the comint buffer.  If the value is `other',
point jumps in all nonselected windows that show the current buffer.
The default value is `nil', which means point does not jump to the end.

   The variable `comint-input-ignoredups' controls whether successive
identical inputs are stored in the input history.  A non-`nil' value
means to omit an input that is the same as the previous input.  The
default is `nil', which means to store each input even if it is equal
to the previous input.

   Three variables customize file name completion.  The variable
`comint-completion-addsuffix' controls whether completion inserts a
space or a slash to indicate a fully completed file or directory name
(non-`nil' means do insert a space or slash).
`comint-completion-recexact', if non-`nil', directs <TAB> to choose the
shortest possible completion if the usual Emacs completion algorithm
cannot add even a single character.  `comint-completion-autolist', if
non-`nil', says to list all the possible completions whenever
completion is not exact.

   The command `comint-dynamic-complete-variable' does variable-name
completion using the environment variables as set within Emacs.  The
variables controlling file name completion apply to variable-name
completion too.  This command is normally available through the menu
bar.

   Command completion normally considers only executable files.  If you
set `shell-command-execonly' to `nil', it considers nonexecutable files
as well.

   You can configure the behavior of `pushd'.  Variables control
whether `pushd' behaves like `cd' if no argument is given
(`shell-pushd-tohome'), pop rather than rotate with a numeric argument
(`shell-pushd-dextract'), and only add directories to the directory
stack if they are not already on it (`shell-pushd-dunique').  The
values you choose should match the underlying shell, of course.


File: emacs,  Node: Remote Host,  Prev: Shell Options,  Up: Shell

Remote Host Shell
-----------------

   Emacs provides two commands for logging in to another computer and
communicating with it through an Emacs buffer.

`M-x telnet <RET> HOSTNAME <RET>'
     Set up a Telnet connection to the computer named HOSTNAME.

`M-x rlogin <RET> HOSTNAME <RET>'
     Set up an Rlogin connection to the computer named HOSTNAME.

   Use `M-x telnet' to set up a Telnet connection to another computer.
(Telnet is the standard Internet protocol for remote login.)  It reads
the host name of the other computer as an argument with the minibuffer.
Once the connection is established, talking to the other computer
works like talking to a subshell: you can edit input with the usual
Emacs commands, and send it a line at a time by typing <RET>.  The
output is inserted in the Telnet buffer interspersed with the input.

   Use `M-x rlogin' to set up an Rlogin connection.  Rlogin is another
remote login communication protocol, essentially much like the Telnet
protocol but incompatible with it, and supported only by certain
systems.  Rlogin's advantages are that you can arrange not to have to
give your user name and password when communicating between two machines
you frequently use, and that you can make an 8-bit-clean connection.
(To do that in Emacs, set `rlogin-explicit-args' to `("-8")' before you
run Rlogin.)

   `M-x rlogin' sets up the default file directory of the Emacs buffer
to access the remote host via FTP (*note File Names::.), and it tracks
the shell commands that change the current directory, just like Shell
mode.

   There are two ways of doing directory tracking in an Rlogin
buffer--either with remote directory names `/HOST:DIR/' or with local
names (that works if the "remote" machine shares file systems with your
machine of origin).  You can use the command
`rlogin-directory-tracking-mode' to switch modes.  No argument means
use remote directory names, a positive argument means use local names,
and a negative argument means turn off directory tracking.


File: emacs,  Node: Emacs Server,  Next: Hardcopy,  Prev: Shell,  Up: Top

Using Emacs as a Server
=======================

   Various programs such as `mail' can invoke your choice of editor to
edit a particular piece of text, such as a message that you are
sending.  By convention, most of these programs use the environment
variable `EDITOR' to specify which editor to run.  If you set `EDITOR'
to `emacs', they invoke Emacs--but in an inconvenient fashion, by
starting a new, separate Emacs process.  This is inconvenient because
it takes time and because the new Emacs process doesn't share the
buffers in the existing Emacs process.

   You can arrange to use your existing Emacs process as the editor for
programs like `mail' by using the Emacs client and Emacs server
programs.  Here is how.

   First, the preparation.  Within Emacs, call the function
`server-start'.  (Your `.emacs' file can do this automatically if you
add the expression `(server-start)' to it.)  Then, outside Emacs, set
the `EDITOR' environment variable to `emacsclient'.  (Note that some
programs use a different environment variable; for example, to make TeX
use `emacsclient', you should set the `TEXEDIT' environment variable to
`emacsclient +%d %s'.)

   Then, whenever any program invokes your specified `EDITOR' program,
the effect is to send a message to your principal Emacs telling it to
visit a file.  (That's what the program `emacsclient' does.)  Emacs
displays the buffer immediately and you can immediately begin editing
it.

   When you've finished editing that buffer, type `C-x #'
(`server-edit').  This saves the file and sends a message back to the
`emacsclient' program telling it to exit.  The programs that use
`EDITOR' wait for the "editor" (actually, `emacsclient') to exit.  `C-x
#' also checks for other pending external requests to edit various
files, and selects the next such file.

   You can switch to a server buffer manually if you wish; you don't
have to arrive at it with `C-x #'.  But `C-x #' is the only way to say
that you are "finished" with one.

   If you set the variable `server-window' to a window or a frame, `C-x
#' displays the server buffer in that window or in that frame.

   While `mail' or another application is waiting for `emacsclient' to
finish, `emacsclient' does not read terminal input.  So the terminal
that `mail' was using is effectively blocked for the duration.  In
order to edit with your principal Emacs, you need to be able to use it
without using that terminal.  There are two ways to do this:

   * Using a window system, run `mail' and the principal Emacs in two
     separate windows.  While `mail' is waiting for `emacsclient', the
     window where it was running is blocked, but you can use Emacs by
     switching windows.

   * Use Shell mode in Emacs to run the other program such as `mail';
     then, `emacsclient' blocks only the subshell under Emacs, and you
     can still use Emacs to edit the file.

   Some programs write temporary files for you to edit.  After you edit
the temporary file, the program reads it back and deletes it.  If the
Emacs server is later asked to edit the same file name, it should assume
this has nothing to do with the previous occasion for that file name.
The server accomplishes this by killing the temporary file's buffer when
you finish with the file.  Use the variable `server-temp-file-regexp'
to specify which files are temporary in this sense; its value should be
a regular expression that matches file names that are temporary.

   If you run `emacsclient' with the option `--no-wait', it returns
immediately without waiting for you to "finish" the buffer in Emacs.


File: emacs,  Node: Hardcopy,  Next: Postscript,  Prev: Emacs Server,  Up: Top

Hardcopy Output
===============

   The Emacs commands for making hardcopy let you print either an entire
buffer or just part of one, either with or without page headers.  See
also the hardcopy commands of Dired (*note Misc File Ops::.)  and the
diary (*note Diary Commands::.).

`M-x print-buffer'
     Print hardcopy of current buffer with page headings containing the
     file name and page number.

`M-x lpr-buffer'
     Print hardcopy of current buffer without page headings.

`M-x print-region'
     Like `print-buffer' but print only the current region.

`M-x lpr-region'
     Like `lpr-buffer' but print only the current region.

   The hardcopy commands (aside from the Postscript commands) pass extra
switches to the `lpr' program based on the value of the variable
`lpr-switches'.  Its value should be a list of strings, each string an
option starting with `-'.  For example, to specify a line width of 80
columns for all the printing you do in Emacs, set `lpr-switches' like
this:

     (setq lpr-switches '("-w80"))

   You can specify the printer to use by setting the variable
`printer-name'.

   The variable `lpr-command' specifies the name of the printer program
to run; the default value depends on your operating system type.  On
most systems, the default is `"lpr"'.  The variable
`lpr-headers-switches' similarly specifies the extra switches to use to
make page headers.  The variable `lpr-add-switches' controls whether to
supply `-T' and `-J' options (suitable for `lpr') to the printer
program: `nil' means don't add them.  `lpr-add-switches' should be
`nil' if your printer program is not compatible with `lpr'.


File: emacs,  Node: Postscript,  Next: Postscript Variables,  Prev: Hardcopy,  Up: Top

Postscript Hardcopy
===================

   These commands convert buffer contents to Postscript, either
printing it or leaving it in another Emacs buffer.

`M-x ps-print-buffer'
     Print hardcopy of the current buffer in Postscript form.

`M-x ps-print-region'
     Print hardcopy of the current region in Postscript form.

`M-x ps-print-buffer-with-faces'
     Print hardcopy of the current buffer in Postscript form, showing
     the faces used in the text by means of Postscript features.

`M-x ps-print-region-with-faces'
     Print hardcopy of the current region in Postscript form, showing
     the faces used in the text.

`M-x ps-spool-buffer'
     Generate Postscript for the current buffer text.

`M-x ps-spool-region'
     Generate Postscript for the current region.

`M-x ps-spool-buffer-with-faces'
     Generate Postscript for the current buffer, showing the faces used.

`M-x ps-spool-region-with-faces'
     Generate Postscript for the current region, showing the faces used.

   The Postscript commands, `ps-print-buffer' and `ps-print-region',
print buffer contents in Postscript form.  One command prints the
entire buffer; the other, just the region.  The corresponding
`-with-faces' commands, `ps-print-buffer-with-faces' and
`ps-print-region-with-faces', use Postscript features to show the faces
(fonts and colors) in the text properties of the text being printed.

   If you are using a color display, you can print a buffer of program
code with color highlighting by turning on Font-Lock mode in that
buffer, and using `ps-print-buffer-with-faces'.

   The commands whose names have `spool' instead of `print' generate
the Postscript output in an Emacs buffer instead of sending it to the
printer.

   The following section describes variables for customizing these
commands.


File: emacs,  Node: Postscript Variables,  Next: Sorting,  Prev: Postscript,  Up: Top

Variables for Postscript Hardcopy
=================================

   All the Postscript hardcopy commands use the variables
`ps-lpr-command' and `ps-lpr-switches' to specify how to print the
output.  `ps-lpr-command' specifies the command name to run,
`ps-lpr-switches' specifies command line options to use, and
`ps-printer-name' specifies the printer.  If you don't set the first
two variables yourself, they take their initial values from
`lpr-command' and `lpr-switches'.  If `ps-printer-name' is `nil',
`printer-name' is used.

   The variable `ps-print-header' controls whether these commands add
header lines to each page--set it to `nil' to turn headers off.  You
can turn off color processing by setting `ps-print-color-p' to `nil'.

   The variable `ps-paper-type' specifies which size of paper to format
for; legitimate values include `a4', `a3', `a4small', `b4', `b5',
`executive', `ledger', `legal', `letter', `letter-small', `statement',
`tabloid'.  The default is `letter'.  You can define additional paper
sizes by changing the variable `ps-page-dimensions-database'.

   The variable `ps-landscape-mode' specifies the orientation of
printing on the page.  The default is `nil', which stands for
"portrait" mode.  Any non-`nil' value specifies "landscape" mode.

   The variable `ps-number-of-columns' specifies the number of columns;
it takes effect in both landscape and portrait mode.  The default is 1.

   The variable `ps-font-family' specifies which font family to use for
printing ordinary text.  Legitimate values include `Courier',
`Helvetica', `NewCenturySchlbk', `Palatino' and `Times'.  The variable
`ps-font-size' specifies the size of the font for ordinary text.  It
defaults to 8.5 points.

   Many other customization variables for these commands are defined and
described in the Lisp file `ps-print.el'.


File: emacs,  Node: Sorting,  Next: Narrowing,  Prev: Postscript Variables,  Up: Top

Sorting Text
============

   Emacs provides several commands for sorting text in the buffer.  All
operate on the contents of the region (the text between point and the
mark).  They divide the text of the region into many "sort records",
identify a "sort key" for each record, and then reorder the records
into the order determined by the sort keys.  The records are ordered so
that their keys are in alphabetical order, or, for numeric sorting, in
numeric order.  In alphabetic sorting, all upper-case letters `A'
through `Z' come before lower-case `a', in accord with the ASCII
character sequence.

   The various sort commands differ in how they divide the text into
sort records and in which part of each record is used as the sort key.
Most of the commands make each line a separate sort record, but some
commands use paragraphs or pages as sort records.  Most of the sort
commands use each entire sort record as its own sort key, but some use
only a portion of the record as the sort key.

`M-x sort-lines'
     Divide the region into lines, and sort by comparing the entire
     text of a line.  A numeric argument means sort into descending
     order.

`M-x sort-paragraphs'
     Divide the region into paragraphs, and sort by comparing the entire
     text of a paragraph (except for leading blank lines).  A numeric
     argument means sort into descending order.

`M-x sort-pages'
     Divide the region into pages, and sort by comparing the entire
     text of a page (except for leading blank lines).  A numeric
     argument means sort into descending order.

`M-x sort-fields'
     Divide the region into lines, and sort by comparing the contents of
     one field in each line.  Fields are defined as separated by
     whitespace, so the first run of consecutive non-whitespace
     characters in a line constitutes field 1, the second such run
     constitutes field 2, etc.

     Specify which field to sort by with a numeric argument: 1 to sort
     by field 1, etc.  A negative argument means count fields from the
     right instead of from the left; thus, minus 1 means sort by the
     last field.  If several lines have identical contents in the field
     being sorted, they keep same relative order that they had in the
     original buffer.

`M-x sort-numeric-fields'
     Like `M-x sort-fields' except the specified field is converted to
     an integer for each line, and the numbers are compared.  `10'
     comes before `2' when considered as text, but after it when
     considered as a number.

`M-x sort-columns'
     Like `M-x sort-fields' except that the text within each line used
     for comparison comes from a fixed range of columns.  See below for
     an explanation.

`M-x reverse-region'
     Reverse the order of the lines in the region.  This is useful for
     sorting into descending order by fields or columns, since those
     sort commands do not have a feature for doing that.

   For example, if the buffer contains this:

     On systems where clash detection (locking of files being edited) is
     implemented, Emacs also checks the first time you modify a buffer
     whether the file has changed on disk since it was last visited or
     saved.  If it has, you are asked to confirm that you want to change
     the buffer.

applying `M-x sort-lines' to the entire buffer produces this:

     On systems where clash detection (locking of files being edited) is
     implemented, Emacs also checks the first time you modify a buffer
     saved.  If it has, you are asked to confirm that you want to change
     the buffer.
     whether the file has changed on disk since it was last visited or

where the upper-case `O' sorts before all lower-case letters.  If you
use `C-u 2 M-x sort-fields' instead, you get this:

     implemented, Emacs also checks the first time you modify a buffer
     saved.  If it has, you are asked to confirm that you want to change
     the buffer.
     On systems where clash detection (locking of files being edited) is
     whether the file has changed on disk since it was last visited or

where the sort keys were `Emacs', `If', `buffer', `systems' and `the'.

   `M-x sort-columns' requires more explanation.  You specify the
columns by putting point at one of the columns and the mark at the other
column.  Because this means you cannot put point or the mark at the
beginning of the first line of the text you want to sort, this command
uses an unusual definition of `region': all of the line point is in is
considered part of the region, and so is all of the line the mark is in,
as well as all the lines in between.

   For example, to sort a table by information found in columns 10 to
15, you could put the mark on column 10 in the first line of the table,
and point on column 15 in the last line of the table, and then run
`sort-columns'.  Equivalently, you could run it with the mark on column
15 in the first line and point on column 10 in the last line.

   This can be thought of as sorting the rectangle specified by point
and the mark, except that the text on each line to the left or right of
the rectangle moves along with the text inside the rectangle.  *Note
Rectangles::.

   Many of the sort commands ignore case differences when comparing, if
`sort-fold-case' is non-`nil'.


File: emacs,  Node: Narrowing,  Next: Two-Column,  Prev: Sorting,  Up: Top

Narrowing
=========

   "Narrowing" means focusing in on some portion of the buffer, making
the rest temporarily inaccessible.  The portion which you can still get
to is called the "accessible portion".  Canceling the narrowing, which
makes the entire buffer once again accessible, is called "widening".
The amount of narrowing in effect in a buffer at any time is called the
buffer's "restriction".

   Narrowing can make it easier to concentrate on a single subroutine or
paragraph by eliminating clutter.  It can also be used to restrict the
range of operation of a replace command or repeating keyboard macro.

`C-x n n'
     Narrow down to between point and mark (`narrow-to-region').

`C-x n w'
     Widen to make the entire buffer accessible again (`widen').

`C-x n p'
     Narrow down to the current page (`narrow-to-page').

`C-x n d'
     Narrow down to the current defun (`narrow-to-defun').

   When you have narrowed down to a part of the buffer, that part
appears to be all there is.  You can't see the rest, you can't move
into it (motion commands won't go outside the accessible part), you
can't change it in any way.  However, it is not gone, and if you save
the file all the inaccessible text will be saved.  The word `Narrow'
appears in the mode line whenever narrowing is in effect.

   The primary narrowing command is `C-x n n' (`narrow-to-region').  It
sets the current buffer's restrictions so that the text in the current
region remains accessible but all text before the region or after the
region is inaccessible.  Point and mark do not change.

   Alternatively, use `C-x n p' (`narrow-to-page') to narrow down to
the current page.  *Note Pages::, for the definition of a page.  `C-x n
d' (`narrow-to-defun') narrows down to the defun containing point
(*note Defuns::.).

   The way to cancel narrowing is to widen with `C-x n w' (`widen').
This makes all text in the buffer accessible again.

   You can get information on what part of the buffer you are narrowed
down to using the `C-x =' command.  *Note Position Info::.

   Because narrowing can easily confuse users who do not understand it,
`narrow-to-region' is normally a disabled command.  Attempting to use
this command asks for confirmation and gives you the option of enabling
it; if you enable the command, confirmation will no longer be required
for it.  *Note Disabling::.


File: emacs,  Node: Two-Column,  Next: Editing Binary Files,  Prev: Narrowing,  Up: Top

Two-Column Editing
==================

   Two-column mode lets you conveniently edit two side-by-side columns
of text.  It uses two side-by-side windows, each showing its own buffer.

   There are three ways to enter two-column mode:

`<F2> 2' or `C-x 6 2'
     Enter two-column mode with the current buffer on the left, and on
     the right, a buffer whose name is based on the current buffer's
     name (`2C-two-columns').  If the right-hand buffer doesn't already
     exist, it starts out empty; the current buffer's contents are not
     changed.

     This command is appropriate when the current buffer is empty or
     contains just one column and you want to add another column.

`<F2> s' or `C-x 6 s'
     Split the current buffer, which contains two-column text, into two
     buffers, and display them side by side (`2C-split').  The current
     buffer becomes the left-hand buffer, but the text in the right-hand
     column is moved into the right-hand buffer.  The current column
     specifies the split point.  Splitting starts with the current line
     and continues to the end of the buffer.

     This command is appropriate when you have a buffer that already
     contains two-column text, and you wish to separate the columns
     temporarily.

`<F2> b BUFFER <RET>'
`C-x 6 b BUFFER <RET>'
     Enter two-column mode using the current buffer as the left-hand
     buffer, and using buffer BUFFER as the right-hand buffer
     (`2C-associate-buffer').

   `<F2> s' or `C-x 6 s' looks for a column separator, which is a
string that appears on each line between the two columns.  You can
specify the width of the separator with a numeric argument to `<F2> s';
that many characters, before point, constitute the separator string.
By default, the width is 1, so the column separator is the character
before point.

   When a line has the separator at the proper place, `<F2> s' puts the
text after the separator into the right-hand buffer, and deletes the
separator.  Lines that don't have the column separator at the proper
place remain unsplit; they stay in the left-hand buffer, and the
right-hand buffer gets an empty line to correspond.  (This is the way
to write a line that "spans both columns while in two-column mode":
write it in the left-hand buffer, and put an empty line in the
right-hand buffer.)

   The command `C-x 6 <RET>' or `<F2> <RET>' (`2C-newline') inserts a
newline in each of the two buffers at corresponding positions.  This is
the easiest way to add a new line to the two-column text while editing
it in split buffers.

   When you have edited both buffers as you wish, merge them with `<F2>
1' or `C-x 6 1' (`2C-merge').  This copies the text from the right-hand
buffer as a second column in the other buffer.  To go back to
two-column editing, use `<F2> s'.

   Use `<F2> d' or `C-x 6 d' to dissociate the two buffers, leaving
each as it stands (`2C-dissociate').  If the other buffer, the one not
current when you type `<F2> d', is empty, `<F2> d' kills it.

