This is Info file ../info/emacs, produced by Makeinfo-1.63 from the
input file emacs.texi.


File: emacs,  Node: Special Diary Entries,  Prev: Adding to Diary,  Up: Diary

Special Diary Entries
---------------------

   In addition to entries based on calendar dates, the diary file can
contain "sexp entries" for regular events such as anniversaries.  These
entries are based on Lisp expressions (sexps) that Emacs evaluates as
it scans the diary file.  Instead of a date, a sexp entry contains `%%'
followed by a Lisp expression which must begin and end with
parentheses.  The Lisp expression determines which dates the entry
applies to.

   Calendar mode provides commands to insert certain commonly used sexp
entries:

`i a'
     Add an anniversary diary entry for the selected date
     (`insert-anniversary-diary-entry').

`i b'
     Add a block diary entry for the current region
     (`insert-block-diary-entry').

`i c'
     Add a cyclic diary entry starting at the date
     (`insert-cyclic-diary-entry').

   If you want to make a diary entry that applies to the anniversary of
a specific date, move point to that date and use the `i a' command.
This displays the end of your diary file in another window and inserts
the anniversary description; you can then type the rest of the diary
entry.  The entry looks like this:

     %%(diary-anniversary 10 31 1948) Arthur's birthday

This entry applies to October 31 in any year after 1948; `10 31 1948'
specifies the date.  (If you are using the European calendar style, the
month and day are interchanged.)  The reason this expression requires a
beginning year is that advanced diary functions can use it to calculate
the number of elapsed years.

   A "block" diary entry applies to a specified range of consecutive
dates.  Here is a block diary entry that applies to all dates from June
24, 1990 through July 10, 1990:

     %%(diary-block 6 24 1990 7 10 1990) Vacation

The `6 24 1990' indicates the starting date and the `7 10 1990'
indicates the stopping date.  (Again, if you are using the European
calendar style, the month and day are interchanged.)

   To insert a block entry, place point and the mark on the two dates
that begin and end the range, and type `i b'.  This command displays
the end of your diary file in another window and inserts the block
description; you can then type the diary entry.

   "Cyclic" diary entries repeat after a fixed interval of days.  To
create one, select the starting date and use the `i c' command.  The
command prompts for the length of interval, then inserts the entry,
which looks like this:

     %%(diary-cyclic 50 3 1 1990) Renew medication

This entry applies to March 1, 1990 and every 50th day following; `3 1
1990' specifies the starting date.  (If you are using the European
calendar style, the month and day are interchanged.)

   All three of these commands make marking diary entries.  To insert a
nonmarking entry, give a numeric argument to the command.  For example,
`C-u i a' makes a nonmarking anniversary diary entry.

   Marking sexp diary entries in the calendar is *extremely*
time-consuming, since every date visible in the calendar window must be
individually checked.  So it's a good idea to make sexp diary entries
nonmarking (with `&') when possible.

   Another sophisticated kind of sexp entry, a "floating" diary entry,
specifies a regularly-occurring event by offsets specified in days,
weeks, and months.  It is comparable to a crontab entry interpreted by
the `cron' utility.  Here is a nonmarking, floating diary entry that
applies to the last Thursday in November:

     &%%(diary-float 11 4 -1) American Thanksgiving

The 11 specifies November (the eleventh month), the 4 specifies Thursday
(the fourth day of the week, where Sunday is numbered zero), and the -1
specifies "last" (1 would mean "first", 2 would mean "second", -2 would
mean "second-to-last", and so on).  The month can be a single month or
a list of months.  Thus you could change the 11 above to `'(1 2 3)' and
have the entry apply to the last Thursday of January, February, and
March.  If the month is `t', the entry applies to all months of the
year.

   Most generally, sexp diary entries can perform arbitrary
computations to determine when they apply.  *Note Sexp Diary Entries:
(elisp)Sexp Diary Entries.


File: emacs,  Node: Appointments,  Next: Daylight Savings,  Prev: Diary,  Up: Calendar/Diary

Appointments
============

   If you have a diary entry for an appointment, and that diary entry
begins with a recognizable time of day, Emacs can warn you, several
minutes beforehand, that that appointment is pending.  Emacs alerts you
to the appointment by displaying a message in the mode line.

   To enable appointment notification, you must enable the time display
feature of Emacs, `M-x display-time' (*note Mode Line::.).  You must
also add the function `appt-make-list' to the `diary-hook', like this:

     (add-hook 'diary-hook 'appt-make-list)

   With these preparations done, when you display the diary (either with
the `d' command in the calendar window or with the `M-x diary'
command), it sets up an appointment list of all the diary entries found
with recognizable times of day, and reminds you just before each of
them.

   For example, suppose the diary file contains these lines:

     Monday
       9:30am Coffee break
      12:00pm Lunch

Then on Mondays, after you have displayed the diary, you will be
reminded at 9:20am about your coffee break and at 11:50am about lunch.

   You can write times in am/pm style (with `12:00am' standing for
midnight and `12:00pm' standing for noon), or 24-hour European/military
style.  You need not be consistent; your diary file can have a mixture
of the two styles.

   Emacs updates the appointments list automatically just after
midnight.  This also displays the next day's diary entries in the diary
buffer, unless you set `appt-display-diary' to `nil'.

   You can also use the appointment notification facility like an alarm
clock.  The command `M-x appt-add' adds entries to the appointment list
without affecting your diary file.  You delete entries from the
appointment list with `M-x appt-delete'.

   You can turn off the appointment notification feature at any time by
setting `appt-issue-message' to `nil'.


File: emacs,  Node: Daylight Savings,  Prev: Appointments,  Up: Calendar/Diary

Daylight Savings Time
=====================

   Emacs understands the difference between standard time and daylight
savings time--the times given for sunrise, sunset, solstices,
equinoxes, and the phases of the moon take that into account.  The rules
for daylight savings time vary from place to place and have also varied
historically from year to year.  To do the job properly, Emacs needs to
know which rules to use.

   Some operating systems keep track of the rules that apply to the
place where you are; on these systems, Emacs gets the information it
needs from the system automatically.  If some or all of this
information is missing, Emacs fills in the gaps with the rules
currently used in Cambridge, Massachusetts.  If the resulting rules are
not what you want, you can tell Emacs the rules to use by setting
certain variables.

   These values should be Lisp expressions that refer to the variable
`year', and evaluate to the Gregorian date on which daylight savings
time starts or (respectively) ends, in the form of a list `(MONTH DAY
YEAR)'.  The values should be `nil' if your area does not use daylight
savings time.

   Emacs uses these expressions to determine the starting date of
daylight savings time for the holiday list and for correcting times of
day in the solar and lunar calculations.

   The values for Cambridge, Massachusetts are as follows:

     (calendar-nth-named-day 1 0 4 year)
     (calendar-nth-named-day -1 0 10 year)

That is, the first 0th day (Sunday) of the fourth month (April) in the
year specified by `year', and the last Sunday of the tenth month
(October) of that year.  If daylight savings time were changed to start
on October 1, you would set `calendar-daylight-savings-starts' to this:

     (list 10 1 year)

   If there is no daylight savings time at your location, or if you want
all times in standard time, set `calendar-daylight-savings-starts' and
`calendar-daylight-savings-ends' to `nil'.

   The variable `calendar-daylight-time-offset' specifies the
difference between daylight savings time and standard time, measured in
minutes.  The value for Cambridge, Massachusetts is 60.

   The two variables `calendar-daylight-savings-starts-time' and
`calendar-daylight-savings-ends-time' specify the number of minutes
after midnight local time when the transition to and from daylight
savings time should occur.  For Cambridge, Massachusetts both variables'
values are 120.


File: emacs,  Node: Gnus,  Next: Shell,  Prev: Calendar/Diary,  Up: Top

Gnus
====

   Gnus is an Emacs package primarily designed for reading and posting
Usenet news.  It can also be used to read and respond to messages from a
number of other sources--mail, remote directories, digests, and so on.

   Here we introduce Gnus and describe several basic features.  For
full details, see *Note Gnus: (gnus)Top.

   To start Gnus, type `M-x gnus RET'.

* Menu:

* Buffers of Gnus::	   The group, summary and article buffers.
* Gnus Startup::	   What you should know about starting Gnus.
* Summary of Gnus::	   A short description of the basic Gnus commands.


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

Gnus Buffers
------------

   As opposed to most normal Emacs packages, Gnus uses a number of
different buffers to display information and to receive commands.  The
three buffers users spend most of their time in are the "group buffer",
the "summary buffer" and the "article buffer".

   The "group buffer" contains a list of groups.  This is the first
buffer Gnus displays when it starts up.  It normally displays only the
groups to which you subscribe and that contain unread articles.  Use
this buffer to select a specific group.

   The "summary buffer" lists one line for each article in a single
group.  By default, the author, the subject and the line number are
displayed for each article, but this is customizable, like most aspects
of Gnus display.  The summary buffer is created when you select a group
in the group buffer, and is killed when you exit the group.  Use this
buffer to select an article.

   The "article buffer" displays the article.  In normal Gnus usage,
you don't select this buffer--all useful article-oriented commands work
in the summary buffer.  But you can select the article buffer, and
execute all Gnus commands from that buffer, if you want to.


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.


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.

   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.


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').

`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').

`C-c C-z'
     Stop the shell or its current subjob if any (`comint-stop-subjob').

`C-c C-\'
     Send quit signal to the shell or its current subjob if any
     (`comint-quit-subjob').

`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.

   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.

   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.


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 use a printer named
`nearme', set `lpr-switches' like this:

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

   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: Sorting,  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'.

   All four of the commands above 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, and
`ps-lpr-switches' specifies command line options to use.  If you don't
set these variables yourself, they take their initial values from
`lpr-command' and `lpr-switches'.

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

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

