1 @c This is part of the Emacs manual.
2 @c Copyright (C) 1985, 86, 87, 93, 94, 95, 97, 2000
3 @c Free Software Foundation, Inc.
4 @c See file emacs.texi for copying conditions.
6 @chapter Miscellaneous Commands
8 This chapter contains several brief topics that do not fit anywhere
9 else: reading netnews, running shell commands and shell subprocesses,
10 using a single shared Emacs for utilities that expect to run an editor
11 as a subprocess, printing hardcopy, sorting text, narrowing display to
12 part of the buffer, editing double-column files and binary files, saving
13 an Emacs session for later resumption, emulating other editors, and
14 various diversions and amusements.
17 @node Gnus, Shell, Calendar/Diary, Top
20 @cindex reading netnews
22 Gnus is an Emacs package primarily designed for reading and posting
23 Usenet news. It can also be used to read and respond to messages from a
24 number of other sources---mail, remote directories, digests, and so on.
26 Here we introduce Gnus and describe several basic features.
28 For full details, see @ref{Top, Gnus,, gnus, The Gnus Manual}.
31 For full details on Gnus, type @kbd{M-x info} and then select the Gnus
36 To start Gnus, type @kbd{M-x gnus @key{RET}}.
39 * Buffers of Gnus:: The group, summary, and article buffers.
40 * Gnus Startup:: What you should know about starting Gnus.
41 * Summary of Gnus:: A short description of the basic Gnus commands.
45 @subsection Gnus Buffers
47 As opposed to most normal Emacs packages, Gnus uses a number of
48 different buffers to display information and to receive commands. The
49 three buffers users spend most of their time in are the @dfn{group
50 buffer}, the @dfn{summary buffer} and the @dfn{article buffer}.
52 The @dfn{group buffer} contains a list of groups. This is the first
53 buffer Gnus displays when it starts up. It normally displays only the
54 groups to which you subscribe and that contain unread articles. Use
55 this buffer to select a specific group.
57 The @dfn{summary buffer} lists one line for each article in a single
58 group. By default, the author, the subject and the line number are
59 displayed for each article, but this is customizable, like most aspects
60 of Gnus display. The summary buffer is created when you select a group
61 in the group buffer, and is killed when you exit the group. Use this
62 buffer to select an article.
64 The @dfn{article buffer} displays the article. In normal Gnus usage,
65 you don't select this buffer---all useful article-oriented commands work
66 in the summary buffer. But you can select the article buffer, and
67 execute all Gnus commands from that buffer, if you want to.
70 @subsection When Gnus Starts Up
72 At startup, Gnus reads your @file{.newsrc} news initialization file
73 and attempts to communicate with the local news server, which is a
74 repository of news articles. The news server need not be the same
75 computer you are logged in on.
77 If you start Gnus and connect to the server, but do not see any
78 newsgroups listed in the group buffer, type @kbd{L} or @kbd{A k} to get
79 a listing of all the groups. Then type @kbd{u} to toggle
80 subscription to groups.
82 The first time you start Gnus, Gnus subscribes you to a few selected
83 groups. All other groups start out as @dfn{killed groups} for you; you
84 can list them with @kbd{A k}. All new groups that subsequently come to
85 exist at the news server become @dfn{zombie groups} for you; type @kbd{A
86 z} to list them. You can subscribe to a group shown in these lists
87 using the @kbd{u} command.
89 When you quit Gnus with @kbd{q}, it automatically records in your
90 @file{.newsrc} and @file{.newsrc.eld} initialization files the
91 subscribed or unsubscribed status of all groups. You should normally
92 not edit these files manually, but you may if you know how.
95 @subsection Summary of Gnus Commands
97 Reading news is a two step process:
101 Choose a group in the group buffer.
104 Select articles from the summary buffer. Each article selected is
105 displayed in the article buffer in a large window, below the summary
106 buffer in its small window.
109 Each Gnus buffer has its own special commands; however, the meanings
110 of any given key in the various Gnus buffers are usually analogous, even
111 if not identical. Here are commands for the group and summary buffers:
114 @kindex q @r{(Gnus Group mode)}
115 @findex gnus-group-exit
117 In the group buffer, update your @file{.newsrc} initialization file
120 In the summary buffer, exit the current group and return to the
121 group buffer. Thus, typing @kbd{q} twice quits Gnus.
123 @kindex L @r{(Gnus Group mode)}
124 @findex gnus-group-list-all-groups
126 In the group buffer, list all the groups available on your news
127 server (except those you have killed). This may be a long list!
129 @kindex l @r{(Gnus Group mode)}
130 @findex gnus-group-list-groups
132 In the group buffer, list only the groups to which you subscribe and
133 which contain unread articles.
135 @kindex u @r{(Gnus Group mode)}
136 @findex gnus-group-unsubscribe-current-group
137 @cindex subscribe groups
138 @cindex unsubscribe groups
140 In the group buffer, unsubscribe from (or subscribe to) the group listed
141 in the line that point is on. When you quit Gnus by typing @kbd{q},
142 Gnus lists in your @file{.newsrc} file which groups you have subscribed
143 to. The next time you start Gnus, you won't see this group,
144 because Gnus normally displays only subscribed-to groups.
146 @kindex C-k @r{(Gnus)}
147 @findex gnus-group-kill-group
149 In the group buffer, ``kill'' the current line's group---don't
150 even list it in @file{.newsrc} from now on. This affects future
151 Gnus sessions as well as the present session.
153 When you quit Gnus by typing @kbd{q}, Gnus writes information
154 in the file @file{.newsrc} describing all newsgroups except those you
157 @kindex SPC @r{(Gnus)}
158 @findex gnus-group-read-group
160 In the group buffer, select the group on the line under the cursor
161 and display the first unread article in that group.
164 In the summary buffer,
168 Select the article on the line under the cursor if none is selected.
171 Scroll the text of the selected article (if there is one).
174 Select the next unread article if at the end of the current article.
177 Thus, you can move through all the articles by repeatedly typing @key{SPC}.
179 @kindex DEL @r{(Gnus)}
181 In the group buffer, move point to the previous group containing
184 @findex gnus-summary-prev-page
185 In the summary buffer, scroll the text of the article backwards.
188 @findex gnus-group-next-unread-group
189 @findex gnus-summary-next-unread-article
191 Move point to the next unread group, or select the next unread article.
194 @findex gnus-group-prev-unread-group
195 @findex gnus-summary-prev-unread-article
197 Move point to the previous unread group, or select the previous
200 @kindex C-n @r{(Gnus Group mode)}
201 @findex gnus-group-next-group
202 @kindex C-p @r{(Gnus Group mode)}
203 @findex gnus-group-prev-group
204 @kindex C-n @r{(Gnus Summary mode)}
205 @findex gnus-summary-next-subject
206 @kindex C-p @r{(Gnus Summary mode)}
207 @findex gnus-summary-prev-subject
210 Move point to the next or previous item, even if it is marked as read.
211 This does not select the article or group on that line.
213 @kindex s @r{(Gnus Summary mode)}
214 @findex gnus-summary-isearch-article
216 In the summary buffer, do an incremental search of the current text in
217 the article buffer, just as if you switched to the article buffer and
220 @kindex M-s @r{(Gnus Summary mode)}
221 @findex gnus-summary-search-article-forward
222 @item M-s @var{regexp} @key{RET}
223 In the summary buffer, search forward for articles containing a match
230 @subsection Where to Look Further
232 @c Too many references to the name of the manual if done with xref in TeX!
233 Gnus is powerful and customizable. Here are references to a few
239 additional topics in @cite{The Gnus Manual}:
243 Follow discussions on specific topics.@*
244 See section ``Threading.''
247 Read digests. See section ``Document Groups.''
250 Refer to and jump to the parent of the current article.@*
251 See section ``Finding the Parent.''
254 Refer to articles by using Message-IDs included in the messages.@*
255 See section ``Article Keymap.''
258 Save articles. See section ``Saving Articles.''
261 Have Gnus score articles according to various criteria, like author
262 name, subject, or string in the body of the articles.@*
263 See section ``Scoring.''
266 Send an article to a newsgroup.@*
267 See section ``Composing Messages.''
273 Follow discussions on specific topics.@*
274 @xref{Threading, , Reading Based on Conversation Threads,
275 gnus, The Gnus Manual}.
278 Read digests. @xref{Document Groups, , , gnus, The Gnus Manual}.
281 Refer to and jump to the parent of the current article.@*
282 @xref{Finding the Parent, , , gnus, The Gnus Manual}.
285 Refer to articles by using Message-IDs included in the messages.@*
286 @xref{Article Keymap, , , gnus, The Gnus Manual}.
289 Save articles. @xref{Saving Articles, , , gnus, The Gnus Manual}.
292 Have Gnus score articles according to various criteria, like author
293 name, subject, or string in the body of the articles.@*
294 @xref{Scoring, , , gnus, The Gnus Manual}.
297 Send an article to a newsgroup.@*
298 @xref{Composing Messages, , , gnus, The Gnus Manual}.
303 @node Shell, Emacs Server, Gnus, Top
304 @section Running Shell Commands from Emacs
306 @cindex shell commands
308 Emacs has commands for passing single command lines to inferior shell
309 processes; it can also run a shell interactively with input and output to
310 an Emacs buffer named @samp{*shell*}.
313 @item M-! @var{cmd} @key{RET}
314 Run the shell command line @var{cmd} and display the output
315 (@code{shell-command}).
316 @item M-| @var{cmd} @key{RET}
317 Run the shell command line @var{cmd} with region contents as input;
318 optionally replace the region with the output
319 (@code{shell-command-on-region}).
321 Run a subshell with input and output through an Emacs buffer.
322 You can then give commands interactively.
324 Run a subshell with input and output through an Emacs buffer.
325 You can then give commands interactively.
326 Full terminal emulation is available.
330 * Single Shell:: How to run one shell command and return.
331 * Interactive Shell:: Permanent shell taking input via Emacs.
332 * Shell Mode:: Special Emacs commands used with permanent shell.
333 * History: Shell History. Repeating previous commands in a shell buffer.
334 * Options: Shell Options. Options for customizing Shell mode.
335 * Terminal emulator:: An Emacs window as a terminal emulator.
336 * Term Mode:: Special Emacs commands used in Term mode.
337 * Paging in Term:: Paging in the terminal emulator.
338 * Remote Host:: Connecting to another computer.
342 @subsection Single Shell Commands
345 @findex shell-command
346 @kbd{M-!} (@code{shell-command}) reads a line of text using the
347 minibuffer and executes it as a shell command in a subshell made just
348 for that command. Standard input for the command comes from the null
349 device. If the shell command produces any output, the output goes into
350 an Emacs buffer named @samp{*Shell Command Output*}, which is displayed
351 in another window but not selected. A numeric argument, as in @kbd{M-1
352 M-!}, directs this command to insert any output into the current buffer.
353 In that case, point is left before the output and the mark is set after
356 If the shell command line ends in @samp{&}, it runs asynchronously.
357 For a synchronous shell command, @code{shell-command} returns the
358 command's exit status (0 means success), when it is called from a Lisp
362 @findex shell-command-on-region
363 @kbd{M-|} (@code{shell-command-on-region}) is like @kbd{M-!} but
364 passes the contents of the region as the standard input to the shell
365 command, instead of no input. If a numeric argument is used, meaning
366 insert the output in the current buffer, then the old region is deleted
367 first and the output replaces it as the contents of the region. It
368 returns the command's exit status when it is called from a Lisp program.
370 @vindex shell-file-name
372 Both @kbd{M-!} and @kbd{M-|} use @code{shell-file-name} to specify the
373 shell to use. This variable is initialized based on your @env{SHELL}
374 environment variable when Emacs is started. If the file name does not
375 specify a directory, the directories in the list @code{exec-path} are
376 searched; this list is initialized based on the environment variable
377 @env{PATH} when Emacs is started. Your @file{.emacs} file can override
378 either or both of these default initializations.@refill
380 Both @kbd{M-!} and @kbd{M-|} wait for the shell command to complete.
381 To stop waiting, type @kbd{C-g} to quit; that terminates the shell
382 command with the signal @code{SIGINT}---the same signal that @kbd{C-c}
383 normally generates in the shell. Emacs waits until the command actually
384 terminates. If the shell command doesn't stop (because it ignores the
385 @code{SIGINT} signal), type @kbd{C-g} again; this sends the command a
386 @code{SIGKILL} signal which is impossible to ignore.
388 To specify a coding system for @kbd{M-!} or @kbd{M-|}, use the command
389 @kbd{C-x @key{RET} c} immediately beforehand. @xref{Specify Coding}.
391 @vindex shell-command-default-error-buffer
392 Error output from the command is normally intermixed with the regular
393 output. If you set the variable
394 @code{shell-command-default-error-buffer} to a string, which is a buffer
395 name, error output is inserted before point in the buffer of that name.
397 @node Interactive Shell
398 @subsection Interactive Inferior Shell
401 To run a subshell interactively, putting its typescript in an Emacs
402 buffer, use @kbd{M-x shell}. This creates (or reuses) a buffer named
403 @samp{*shell*} and runs a subshell with input coming from and output going
404 to that buffer. That is to say, any ``terminal output'' from the subshell
405 goes into the buffer, advancing point, and any ``terminal input'' for
406 the subshell comes from text in the buffer. To give input to the subshell,
407 go to the end of the buffer and type the input, terminated by @key{RET}.
409 Emacs does not wait for the subshell to do anything. You can switch
410 windows or buffers and edit them while the shell is waiting, or while it is
411 running a command. Output from the subshell waits until Emacs has time to
412 process it; this happens whenever Emacs is waiting for keyboard input or
415 To make multiple subshells, rename the buffer @samp{*shell*} to
416 something different using @kbd{M-x rename-uniquely}. Then type @kbd{M-x
417 shell} again to create a new buffer @samp{*shell*} with its own
418 subshell. If you rename this buffer as well, you can create a third
419 one, and so on. All the subshells run independently and in parallel.
421 @vindex explicit-shell-file-name
422 @cindex @env{ESHELL} environment variable
423 @cindex @env{SHELL} environment variable
424 The file name used to load the subshell is the value of the variable
425 @code{explicit-shell-file-name}, if that is non-@code{nil}. Otherwise,
426 the environment variable @env{ESHELL} is used, or the environment
427 variable @env{SHELL} if there is no @env{ESHELL}. If the file name
428 specified is relative, the directories in the list @code{exec-path} are
429 searched; this list is initialized based on the environment variable
430 @env{PATH} when Emacs is started. Your @file{.emacs} file can override
431 either or both of these default initializations.
433 To specify a coding system for the shell, you can use the command
434 @kbd{C-x @key{RET} c} immediately before @kbd{M-x shell}. You can also
435 specify a coding system after starting the shell by using @kbd{C-x
436 @key{RET} p} in the shell buffer. @xref{Specify Coding}.
438 As soon as the subshell is started, it is sent as input the contents
439 of the file @file{~/.emacs_@var{shellname}}, if that file exists, where
440 @var{shellname} is the name of the file that the shell was loaded from.
441 For example, if you use bash, the file sent to it is
442 @file{~/.emacs_bash}.
444 @vindex shell-pushd-regexp
445 @vindex shell-popd-regexp
446 @vindex shell-cd-regexp
447 @code{cd}, @code{pushd} and @code{popd} commands given to the inferior
448 shell are watched by Emacs so it can keep the @samp{*shell*} buffer's
449 default directory the same as the shell's working directory. These
450 commands are recognized syntactically by examining lines of input that are
451 sent. If you use aliases for these commands, you can tell Emacs to
452 recognize them also. For example, if the value of the variable
453 @code{shell-pushd-regexp} matches the beginning of a shell command line,
454 that line is regarded as a @code{pushd} command. Change this variable when
455 you add aliases for @samp{pushd}. Likewise, @code{shell-popd-regexp} and
456 @code{shell-cd-regexp} are used to recognize commands with the meaning of
457 @samp{popd} and @samp{cd}. These commands are recognized only at the
458 beginning of a shell command line.@refill
460 @vindex shell-set-directory-error-hook
461 If Emacs gets an error while trying to handle what it believes is a
462 @samp{cd}, @samp{pushd} or @samp{popd} command, it runs the hook
463 @code{shell-set-directory-error-hook} (@pxref{Hooks}).
466 If Emacs does not properly track changes in the current directory of
467 the subshell, use the command @kbd{M-x dirs} to ask the shell what its
468 current directory is. This command works for shells that support the
469 most common command syntax; it may not work for unusual shells.
471 @findex dirtrack-mode
472 You can also use @kbd{M-x dirtrack-mode} to enable (or disable) an
473 alternative and more aggressive method of tracking changes in the
476 Emacs defines the environment variable @env{EMACS} in the subshell,
477 with value @code{t}. A shell script can check this variable to
478 determine whether it has been run from an Emacs subshell.
481 @subsection Shell Mode
485 Shell buffers use Shell mode, which defines several special keys
486 attached to the @kbd{C-c} prefix. They are chosen to resemble the usual
487 editing and job control characters present in shells that are not under
488 Emacs, except that you must type @kbd{C-c} first. Here is a complete list
489 of the special key bindings of Shell mode:
493 @kindex RET @r{(Shell mode)}
494 @findex comint-send-input
495 At end of buffer send line as input; otherwise, copy current line to end
496 of buffer and send it (@code{comint-send-input}). When a line is
497 copied, any text at the beginning of the line that matches the variable
498 @code{shell-prompt-pattern} is left out; this variable's value should be
499 a regexp string that matches the prompts that your shell uses.
502 @kindex TAB @r{(Shell mode)}
503 @findex comint-dynamic-complete
504 Complete the command name or file name before point in the shell buffer
505 (@code{comint-dynamic-complete}). @key{TAB} also completes history
506 references (@pxref{History References}) and environment variable names.
508 @vindex shell-completion-fignore
509 @vindex comint-completion-fignore
510 The variable @code{shell-completion-fignore} specifies a list of file
511 name extensions to ignore in Shell mode completion. The default setting
512 ignores file names ending in @samp{~}, @samp{#} or @samp{%}. Other
513 related Comint modes use the variable @code{comint-completion-fignore}
517 @kindex M-? @r{(Shell mode)}
518 @findex comint-dynamic-list-filename@dots{}
519 Display temporarily a list of the possible completions of the file name
520 before point in the shell buffer
521 (@code{comint-dynamic-list-filename-completions}).
524 @kindex C-d @r{(Shell mode)}
525 @findex comint-delchar-or-maybe-eof
526 Either delete a character or send @sc{eof}
527 (@code{comint-delchar-or-maybe-eof}). Typed at the end of the shell
528 buffer, @kbd{C-d} sends @sc{eof} to the subshell. Typed at any other
529 position in the buffer, @kbd{C-d} deletes a character as usual.
532 @kindex C-c C-a @r{(Shell mode)}
534 Move to the beginning of the line, but after the prompt if any
535 (@code{comint-bol}). If you repeat this command twice in a row, the
536 second time it moves back to the process mark, which is the beginning of
537 the input that you have not yet sent to the subshell. (Normally that is
538 the same place---the end of the prompt on this line---but after @kbd{C-c
539 @key{SPC}} the process mark may be in a previous line.)
542 Accumulate multiple lines of input, then send them together. This
543 command inserts a newline before point, but does not send the preceding
544 text as input to the subshell---at least, not yet. Both lines, the one
545 before this newline and the one after, will be sent together (along with
546 the newline that separates them), when you type @key{RET}.
549 @kindex C-c C-u @r{(Shell mode)}
550 @findex comint-kill-input
551 Kill all text pending at end of buffer to be sent as input
552 (@code{comint-kill-input}).
555 @kindex C-c C-w @r{(Shell mode)}
556 Kill a word before point (@code{backward-kill-word}).
559 @kindex C-c C-c @r{(Shell mode)}
560 @findex comint-interrupt-subjob
561 Interrupt the shell or its current subjob if any
562 (@code{comint-interrupt-subjob}). This command also kills
563 any shell input pending in the shell buffer and not yet sent.
566 @kindex C-c C-z @r{(Shell mode)}
567 @findex comint-stop-subjob
568 Stop the shell or its current subjob if any (@code{comint-stop-subjob}).
569 This command also kills any shell input pending in the shell buffer and
573 @findex comint-quit-subjob
574 @kindex C-c C-\ @r{(Shell mode)}
575 Send quit signal to the shell or its current subjob if any
576 (@code{comint-quit-subjob}). This command also kills any shell input
577 pending in the shell buffer and not yet sent.
580 @kindex C-c C-o @r{(Shell mode)}
581 @findex comint-kill-output
582 Kill the last batch of output from a shell command
583 (@code{comint-kill-output}). This is useful if a shell command spews
584 out lots of output that just gets in the way.
588 @kindex C-c C-r @r{(Shell mode)}
589 @kindex C-M-l @r{(Shell mode)}
590 @findex comint-show-output
591 Scroll to display the beginning of the last batch of output at the top
592 of the window; also move the cursor there (@code{comint-show-output}).
595 @kindex C-c C-e @r{(Shell mode)}
596 @findex comint-show-maximum-output
597 Scroll to put the end of the buffer at the bottom of the window
598 (@code{comint-show-maximum-output}).
601 @kindex C-c C-f @r{(Shell mode)}
602 @findex shell-forward-command
603 @vindex shell-command-regexp
604 Move forward across one shell command, but not beyond the current line
605 (@code{shell-forward-command}). The variable @code{shell-command-regexp}
606 specifies how to recognize the end of a command.
609 @kindex C-c C-b @r{(Shell mode)}
610 @findex shell-backward-command
611 Move backward across one shell command, but not beyond the current line
612 (@code{shell-backward-command}).
615 @kindex C-c C-l @r{(Shell mode)}
616 @findex comint-dynamic-list-input-ring
617 Display the buffer's history of shell commands in another window
618 (@code{comint-dynamic-list-input-ring}).
621 Ask the shell what its current directory is, so that Emacs can agree
624 @item M-x send-invisible @key{RET} @var{text} @key{RET}
625 @findex send-invisible
626 Send @var{text} as input to the shell, after reading it without
627 echoing. This is useful when a shell command runs a program that asks
630 Alternatively, you can arrange for Emacs to notice password prompts
631 and turn off echoing for them, as follows:
634 (add-hook 'comint-output-filter-functions
635 'comint-watch-for-password-prompt)
638 @item M-x comint-continue-subjob
639 @findex comint-continue-subjob
640 Continue the shell process. This is useful if you accidentally suspend
641 the shell process.@footnote{You should not suspend the shell process.
642 Suspending a subjob of the shell is a completely different matter---that
643 is normal practice, but you must use the shell to continue the subjob;
644 this command won't do it.}
646 @item M-x comint-strip-ctrl-m
647 @findex comint-strip-ctrl-m
648 Discard all control-M characters from the current group of shell output.
649 The most convenient way to use this command is to make it run
650 automatically when you get output from the subshell. To do that,
651 evaluate this Lisp expression:
654 (add-hook 'comint-output-filter-functions
655 'comint-strip-ctrl-m)
658 @item M-x comint-truncate-buffer
659 @findex comint-truncate-buffer
660 This command truncates the shell buffer to a certain maximum number of
661 lines, specified by the variable @code{comint-buffer-maximum-size}.
662 Here's how to do this automatically each time you get output from the
666 (add-hook 'comint-output-filter-functions
667 'comint-truncate-buffer)
671 Shell mode also customizes the paragraph commands so that only shell
672 prompts start new paragraphs. Thus, a paragraph consists of an input
673 command plus the output that follows it in the buffer.
677 Shell mode is a derivative of Comint mode, a general-purpose mode for
678 communicating with interactive subprocesses. Most of the features of
679 Shell mode actually come from Comint mode, as you can see from the
680 command names listed above. The special features of Shell mode in
681 particular include the choice of regular expression for detecting
682 prompts, the directory tracking feature, and a few user commands.
684 Other Emacs features that use variants of Comint mode include GUD
685 (@pxref{Debuggers}) and @kbd{M-x run-lisp} (@pxref{External Lisp}).
688 You can use @kbd{M-x comint-run} to execute any program of your choice
689 in a subprocess using unmodified Comint mode---without the
690 specializations of Shell mode.
693 @subsection Shell Command History
695 Shell buffers support three ways of repeating earlier commands. You
696 can use the same keys used in the minibuffer; these work much as they do
697 in the minibuffer, inserting text from prior commands while point
698 remains always at the end of the buffer. You can move through the
699 buffer to previous inputs in their original place, then resubmit them or
700 copy them to the end. Or you can use a @samp{!}-style history
704 * Ring: Shell Ring. Fetching commands from the history list.
705 * Copy: Shell History Copying. Moving to a command and then copying it.
706 * History References:: Expanding @samp{!}-style history references.
710 @subsubsection Shell History Ring
713 @findex comint-previous-input
714 @kindex M-p @r{(Shell mode)}
716 Fetch the next earlier old shell command.
718 @kindex M-n @r{(Shell mode)}
719 @findex comint-next-input
721 Fetch the next later old shell command.
723 @kindex M-r @r{(Shell mode)}
724 @kindex M-s @r{(Shell mode)}
725 @findex comint-previous-matching-input
726 @findex comint-next-matching-input
727 @item M-r @var{regexp} @key{RET}
728 @itemx M-s @var{regexp} @key{RET}
729 Search backwards or forwards for old shell commands that match @var{regexp}.
731 @item C-c C-x @r{(Shell mode)}
732 @findex comint-get-next-from-history
733 Fetch the next subsequent command from the history.
736 Shell buffers provide a history of previously entered shell commands. To
737 reuse shell commands from the history, use the editing commands @kbd{M-p},
738 @kbd{M-n}, @kbd{M-r} and @kbd{M-s}. These work just like the minibuffer
739 history commands except that they operate on the text at the end of the
740 shell buffer, where you would normally insert text to send to the shell.
742 @kbd{M-p} fetches an earlier shell command to the end of the shell buffer.
743 Successive use of @kbd{M-p} fetches successively earlier shell commands,
744 each replacing any text that was already present as potential shell input.
745 @kbd{M-n} does likewise except that it finds successively more recent shell
746 commands from the buffer.
748 The history search commands @kbd{M-r} and @kbd{M-s} read a regular
749 expression and search through the history for a matching command. Aside
750 from the choice of which command to fetch, they work just like @kbd{M-p}
751 and @kbd{M-r}. If you enter an empty regexp, these commands reuse the
752 same regexp used last time.
754 When you find the previous input you want, you can resubmit it by
755 typing @key{RET}, or you can edit it first and then resubmit it if you
758 Often it is useful to reexecute several successive shell commands that
759 were previously executed in sequence. To do this, first find and
760 reexecute the first command of the sequence. Then type @kbd{C-c C-x};
761 that will fetch the following command---the one that follows the command
762 you just repeated. Then type @key{RET} to reexecute this command. You
763 can reexecute several successive commands by typing @kbd{C-c C-x
764 @key{RET}} over and over.
766 These commands get the text of previous shell commands from a special
767 history list, not from the shell buffer itself. Thus, editing the shell
768 buffer, or even killing large parts of it, does not affect the history
769 that these commands access.
771 @vindex shell-input-ring-file-name
772 Some shells store their command histories in files so that you can
773 refer to previous commands from previous shell sessions. Emacs reads
774 the command history file for your chosen shell, to initialize its own
775 command history. The file name is @file{~/.bash_history} for bash,
776 @file{~/.sh_history} for ksh, and @file{~/.history} for other shells.
778 @node Shell History Copying
779 @subsubsection Shell History Copying
782 @kindex C-c C-p @r{(Shell mode)}
783 @findex comint-previous-prompt
785 Move point to the previous prompt (@code{comint-previous-prompt}).
787 @kindex C-c C-n @r{(Shell mode)}
788 @findex comint-next-prompt
790 Move point to the following prompt (@code{comint-next-prompt}).
792 @kindex C-c RET @r{(Shell mode)}
793 @findex comint-copy-old-input
795 Copy the input command which point is in, inserting the copy at the end
796 of the buffer (@code{comint-copy-old-input}). This is useful if you
797 move point back to a previous command. After you copy the command, you
798 can submit the copy as input with @key{RET}. If you wish, you can
799 edit the copy before resubmitting it.
802 Moving to a previous input and then copying it with @kbd{C-c
803 @key{RET}} produces the same results---the same buffer contents---that
804 you would get by using @kbd{M-p} enough times to fetch that previous
805 input from the history list. However, @kbd{C-c @key{RET}} copies the
806 text from the buffer, which can be different from what is in the history
807 list if you edit the input text in the buffer after it has been sent.
809 @node History References
810 @subsubsection Shell History References
811 @cindex history reference
813 Various shells including csh and bash support @dfn{history references}
814 that begin with @samp{!} and @samp{^}. Shell mode can understand these
815 constructs and perform the history substitution for you. If you insert
816 a history reference and type @key{TAB}, this searches the input history
817 for a matching command, performs substitution if necessary, and places
818 the result in the buffer in place of the history reference. For
819 example, you can fetch the most recent command beginning with @samp{mv}
820 with @kbd{! m v @key{TAB}}. You can edit the command if you wish, and
821 then resubmit the command to the shell by typing @key{RET}.
823 @vindex shell-prompt-pattern
824 @vindex comint-prompt-regexp
825 History references take effect only following a shell prompt. The
826 variable @code{shell-prompt-pattern} specifies how to recognize a shell
827 prompt. Comint modes in general use the variable
828 @code{comint-prompt-regexp} to specify how to find a prompt; Shell mode
829 uses @code{shell-prompt-pattern} to set up the local value of
830 @code{comint-prompt-regexp}.
832 @vindex comint-input-autoexpand
833 Shell mode can optionally expand history references in the buffer when
834 you send them to the shell. To request this, set the variable
835 @code{comint-input-autoexpand} to @code{input}.
837 @findex comint-magic-space
838 You can make @key{SPC} perform history expansion by binding @key{SPC} to
839 the command @code{comint-magic-space}.
842 @subsection Shell Mode Options
844 @vindex comint-scroll-to-bottom-on-input
845 If the variable @code{comint-scroll-to-bottom-on-input} is
846 non-@code{nil}, insertion and yank commands scroll the selected window
847 to the bottom before inserting.
849 @vindex comint-scroll-show-maximum-output
850 If @code{comint-scroll-show-maximum-output} is non-@code{nil}, then
851 scrolling due to arrival of output tries to place the last line of text
852 at the bottom line of the window, so as to show as much useful text as
853 possible. (This mimics the scrolling behavior of many terminals.)
854 The default is @code{nil}.
856 @vindex comint-scroll-to-bottom-on-output
857 By setting @code{comint-scroll-to-bottom-on-output}, you can opt for
858 having point jump to the end of the buffer whenever output arrives---no
859 matter where in the buffer point was before. If the value is
860 @code{this}, point jumps in the selected window. If the value is
861 @code{all}, point jumps in each window that shows the comint buffer. If
862 the value is @code{other}, point jumps in all nonselected windows that
863 show the current buffer. The default value is @code{nil}, which means
864 point does not jump to the end.
866 @vindex comint-input-ignoredups
867 The variable @code{comint-input-ignoredups} controls whether successive
868 identical inputs are stored in the input history. A non-@code{nil}
869 value means to omit an input that is the same as the previous input.
870 The default is @code{nil}, which means to store each input even if it is
871 equal to the previous input.
873 @vindex comint-completion-addsuffix
874 @vindex comint-completion-recexact
875 @vindex comint-completion-autolist
876 Three variables customize file name completion. The variable
877 @code{comint-completion-addsuffix} controls whether completion inserts a
878 space or a slash to indicate a fully completed file or directory name
879 (non-@code{nil} means do insert a space or slash).
880 @code{comint-completion-recexact}, if non-@code{nil}, directs @key{TAB}
881 to choose the shortest possible completion if the usual Emacs completion
882 algorithm cannot add even a single character.
883 @code{comint-completion-autolist}, if non-@code{nil}, says to list all
884 the possible completions whenever completion is not exact.
886 @findex comint-dynamic-complete-variable
887 The command @code{comint-dynamic-complete-variable} does variable-name
888 completion using the environment variables as set within Emacs. The
889 variables controlling file name completion apply to variable-name
890 completion too. This command is normally available through the menu
893 @vindex shell-command-execonly
894 Command completion normally considers only executable files.
895 If you set @code{shell-command-execonly} to @code{nil},
896 it considers nonexecutable files as well.
898 @findex shell-pushd-tohome
899 @findex shell-pushd-dextract
900 @findex shell-pushd-dunique
901 You can configure the behavior of @samp{pushd}. Variables control
902 whether @samp{pushd} behaves like @samp{cd} if no argument is given
903 (@code{shell-pushd-tohome}), pop rather than rotate with a numeric
904 argument (@code{shell-pushd-dextract}), and only add directories to the
905 directory stack if they are not already on it
906 (@code{shell-pushd-dunique}). The values you choose should match the
907 underlying shell, of course.
909 @node Terminal emulator
910 @subsection Interactive Inferior Shell with Terminal Emulator
913 To run a subshell in a terminal emulator, putting its typescript in an Emacs
914 buffer, use @kbd{M-x term}. This creates (or reuses) a buffer named
915 @samp{*term*} and runs a subshell with input coming from your keyboard and
916 output going to that buffer.
918 All the normal keys that you type are sent without any interpretation
919 by Emacs directly to the subshell, as ``terminal input''.
920 Any ``echo'' of your input is the responsibility of the subshell.
921 (The exception is the terminal escape character,
922 which by default is @kbd{C-c}. @xref{Term Mode}.)
923 Any ``terminal output'' from the subshell goes into the buffer,
926 Some programs (such as Emacs itself) need to control the
927 appearance on the terminal screen in detail. They do this by
928 sending special control codes. The exact control
929 codes needed vary from terminal to terminal, but nowadays
930 most terminals and terminal emulators (including @code{xterm})
931 understand the ANSI-standard (VT100-style) escape sequences.
932 Term mode also understands these escape sequences,
933 and for each control code does the appropriate thing
934 to change the buffer so that the appearance of the window
935 matches what it would be on a real terminal.
936 Thus you can actually run Emacs inside an Emacs Term window!
938 Emacs does not wait for the subshell to do anything. You can switch
939 windows or buffers and edit them while the shell is waiting, or while
940 it is running a command. Output from the subshell waits until Emacs
941 has time to process it; this happens whenever Emacs is waiting for
942 keyboard input or for time to elapse.
944 To make multiple terminal emulators, rename the buffer @samp{*term*}
945 to something different using @kbd{M-x rename-uniquely},
946 just as with Shell mode.
948 The file name used to load the subshell is determined
949 the same way as for Shell mode.
951 Unlike Shell mode, Term mode does not track the current directory
952 by examining your input. Instead, if you use a programmable
953 shell, you can have it tell Term what the current directory is.
954 This is done automatically by @code{bash} version 1.15 and later.
957 @subsection Term Mode
961 Term uses Term mode, which has two input modes:
962 In line mode, Term basically acts like Shell mode. @xref{Shell Mode}.
963 In Char mode, each character is sent directly to the inferior subshell,
964 except for the Term escape character, normally @kbd{C-c}.
966 To switch between line and char mode, use these commands:
968 @kindex C-c C-k @r{(Term mode)}
969 @findex term-char-mode
971 Switch to line mode. Do nothing if already in line mode.
973 @kindex C-c C-j @r{(Term mode)}
974 @findex term-line-mode
976 Switch to char mode. Do nothing if already in char mode.
979 The following commands are only available in Char mode:
982 Send a literal @key{C-c} to the sub-shell.
985 A prefix command to access the global @key{C-x} commands conveniently.
986 For example, @kbd{C-c C-x o} invokes the global binding of
987 @kbd{C-x o}, which is normally @samp{other-window}.
991 @subsection Paging in the terminal emulator
993 Term mode has a pager feature. When the pager is enabled,
994 term mode will pause at the end of each screenful.
997 @kindex C-c C-q @r{(Term mode)}
998 @findex term-pager-toggle
1000 Toggles the pager feature: Disables the pager if it is enabled,
1001 and vice versa. This works in both line and char modes.
1002 If the pager enabled, the mode-line contains the word @samp{page}.
1005 If the pager is enabled, and Term receives more than a screenful
1006 of output since your last input, Term will enter More break mode.
1007 This is indicated by @samp{**MORE**} in the mode-line.
1008 Type a @kbd{Space} to display the next screenful of output.
1009 Type @kbd{?} to see your other options. The interface is similar
1010 to the Unix @code{more} program.
1013 @subsection Remote Host Shell
1015 @cindex connecting to remote host
1019 You can login to a remote computer, using whatever commands you
1020 would from a regular terminal (e.g.@: using the @code{telnet} or
1021 @code{rlogin} commands), from a Term window.
1023 A program that asks you for a password will normally suppress
1024 echoing of the password, so the password will not show up in the buffer.
1025 This will happen just as if you were using a real terminal, if
1026 the buffer is in char mode. If it is in line mode, the password
1027 will be temporarily visible, but will be erased when you hit return.
1028 (This happens automatically; there is no special password processing.)
1030 When you log in to a different machine, you need to specify the
1031 type of terminal your using. Terminal types @samp{ansi}
1032 or @samp{vt100} will work on most systems.
1034 @c If you are talking to a Bourne-compatible
1035 @c shell, and your system understands the @env{TERMCAP} variable,
1036 @c you can use the command @kbd{M-x shell-send-termcap}, which
1037 @c sends a string specifying the terminal type and size.
1038 @c (This command is also useful after the window has changed size.)
1040 @c You can of course run @samp{gdb} on that remote computer. One useful
1041 @c trick: If you invoke gdb with the @code{--fullname} option,
1042 @c it will send special commands to Emacs that will cause Emacs to
1043 @c pop up the source files you're debugging. This will work
1044 @c whether or not gdb is running on a different computer than Emacs,
1045 @c as long as Emacs can access the source files specified by gdb.
1047 You cannot log into to a remove comuter using the Shell mode.
1048 @c (This will change when Shell is re-written to use Term.)
1049 Instead, Emacs provides two commands for logging in to another computer
1050 and communicating with it through an Emacs buffer.
1053 @item M-x telnet @key{RET} @var{hostname} @key{RET}
1054 Set up a Telnet connection to the computer named @var{hostname}.
1055 @item M-x rlogin @key{RET} @var{hostname} @key{RET}
1056 Set up an Rlogin connection to the computer named @var{hostname}.
1060 Use @kbd{M-x telnet} to set up a Telnet connection to another
1061 computer. (Telnet is the standard Internet protocol for remote login.)
1062 It reads the host name of the other computer as an argument with the
1063 minibuffer. Once the connection is established, talking to the other
1064 computer works like talking to a subshell: you can edit input with the
1065 usual Emacs commands, and send it a line at a time by typing @key{RET}.
1066 The output is inserted in the Telnet buffer interspersed with the input.
1069 @vindex rlogin-explicit-args
1070 Use @kbd{M-x rlogin} to set up an Rlogin connection. Rlogin is
1071 another remote login communication protocol, essentially much like the
1072 Telnet protocol but incompatible with it, and supported only by certain
1073 systems. Rlogin's advantages are that you can arrange not to have to
1074 give your user name and password when communicating between two machines
1075 you frequently use, and that you can make an 8-bit-clean connection.
1076 (To do that in Emacs, set @code{rlogin-explicit-args} to @code{("-8")}
1077 before you run Rlogin.)
1079 @kbd{M-x rlogin} sets up the default file directory of the Emacs
1080 buffer to access the remote host via FTP (@pxref{File Names}), and it
1081 tracks the shell commands that change the current directory, just like
1084 @findex rlogin-directory-tracking-mode
1085 There are two ways of doing directory tracking in an Rlogin
1086 buffer---either with remote directory names
1087 @file{/@var{host}:@var{dir}/} or with local names (that works if the
1088 ``remote'' machine shares file systems with your machine of origin).
1089 You can use the command @code{rlogin-directory-tracking-mode} to switch
1090 modes. No argument means use remote directory names, a positive
1091 argument means use local names, and a negative argument means turn
1092 off directory tracking.
1094 @node Emacs Server, Hardcopy, Shell, Top
1095 @section Using Emacs as a Server
1097 @cindex Emacs as a server
1098 @cindex server, using Emacs as
1099 @cindex @env{EDITOR} environment variable
1101 Various programs such as @code{mail} can invoke your choice of editor
1102 to edit a particular piece of text, such as a message that you are
1103 sending. By convention, most of these programs use the environment
1104 variable @env{EDITOR} to specify which editor to run. If you set
1105 @env{EDITOR} to @samp{emacs}, they invoke Emacs---but in an
1106 inconvenient fashion, by starting a new, separate Emacs process. This
1107 is inconvenient because it takes time and because the new Emacs process
1108 doesn't share the buffers in the existing Emacs process.
1110 You can arrange to use your existing Emacs process as the editor for
1111 programs like @code{mail} by using the Emacs client and Emacs server
1112 programs. Here is how.
1114 @cindex @env{TEXEDIT} environment variable
1115 First, the preparation. Within Emacs, call the function
1116 @code{server-start}. (Your @file{.emacs} file can do this automatically
1117 if you add the expression @code{(server-start)} to it.) Then, outside
1118 Emacs, set the @env{EDITOR} environment variable to @samp{emacsclient}.
1119 (Note that some programs use a different environment variable; for
1120 example, to make @TeX{} use @samp{emacsclient}, you should set the
1121 @env{TEXEDIT} environment variable to @samp{emacsclient +%d %s}.)
1125 Then, whenever any program invokes your specified @env{EDITOR}
1126 program, the effect is to send a message to your principal Emacs telling
1127 it to visit a file. (That's what the program @code{emacsclient} does.)
1128 Emacs displays the buffer immediately and you can immediately begin
1131 When you've finished editing that buffer, type @kbd{C-x #}
1132 (@code{server-edit}). This saves the file and sends a message back to
1133 the @code{emacsclient} program telling it to exit. The programs that
1134 use @env{EDITOR} wait for the ``editor'' (actually, @code{emacsclient})
1135 to exit. @kbd{C-x #} also checks for other pending external requests
1136 to edit various files, and selects the next such file.
1138 You can switch to a server buffer manually if you wish; you don't have
1139 to arrive at it with @kbd{C-x #}. But @kbd{C-x #} is the only way to
1140 say that you are ``finished'' with one.
1142 @vindex server-window
1143 If you set the variable @code{server-window} to a window or a frame,
1144 @kbd{C-x #} displays the server buffer in that window or in that frame.
1146 While @code{mail} or another application is waiting for
1147 @code{emacsclient} to finish, @code{emacsclient} does not read terminal
1148 input. So the terminal that @code{mail} was using is effectively
1149 blocked for the duration. In order to edit with your principal Emacs,
1150 you need to be able to use it without using that terminal. There are
1151 two ways to do this:
1155 Using a window system, run @code{mail} and the principal Emacs in two
1156 separate windows. While @code{mail} is waiting for @code{emacsclient},
1157 the window where it was running is blocked, but you can use Emacs by
1161 Use Shell mode in Emacs to run the other program such as @code{mail};
1162 then, @code{emacsclient} blocks only the subshell under Emacs, and you
1163 can still use Emacs to edit the file.
1166 @vindex server-temp-file-regexp
1167 Some programs write temporary files for you to edit. After you edit
1168 the temporary file, the program reads it back and deletes it. If the
1169 Emacs server is later asked to edit the same file name, it should assume
1170 this has nothing to do with the previous occasion for that file name.
1171 The server accomplishes this by killing the temporary file's buffer when
1172 you finish with the file. Use the variable
1173 @code{server-temp-file-regexp} to specify which files are temporary in
1174 this sense; its value should be a regular expression that matches file
1175 names that are temporary.
1177 If you run @code{emacsclient} with the option @samp{--no-wait}, it
1178 returns immediately without waiting for you to ``finish'' the buffer in
1181 If you have forgotten to start Emacs, then the option
1182 @samp{--alternate-editor=@var{command}} may be useful. It specifies a
1183 command to run if @code{emacsclient} fails to contact Emacs. For
1184 example, the following setting for the @var{EDITOR} environment variable
1185 will always give an editor, even if Emacs is not running.
1188 EDITOR="emacsclient --alternate-editor vi +%d %s"
1191 The environment variable @var{ALTERNATE_EDITOR} has the same effect, but
1192 the value of the @samp{--alternate-editor} takes precedence.
1195 Alternatively, the file @file{etc/emacs.bash} defines a function for
1196 @command{bash} which will use a running Emacs server or start one if
1200 * Invoking emacsclient::
1203 @node Invoking emacsclient,, Emacs Server, Emacs Server
1204 @section Invoking @code{emacsclient}
1206 To run the @code{emacsclient} program, specify file names as arguments,
1207 and optionally line numbers as well. Do it like this:
1210 emacsclient @r{@{}@r{[}+@var{line}@r{]} @var{filename}@r{@}}@dots{}
1213 This tells Emacs to visit each of the specified files; if you specify a
1214 line number for a certain file, Emacs moves to that line in the file.
1216 Ordinarily, @code{emacsclient} does not return until you use the
1217 @kbd{C-x #} command on each of these buffers. When that happens, Emacs
1218 sends a message to the @code{emacsclient} program telling it to return.
1220 But if you use the option @samp{-n} or @samp{--no-wait} when running
1221 @code{emacsclient}, then it returns immediately. (You can take as long
1222 as you like to edit the files in Emacs.)
1225 @node Hardcopy, PostScript, Emacs Server, Top
1226 @section Hardcopy Output
1229 The Emacs commands for making hardcopy let you print either an entire
1230 buffer or just part of one, either with or without page headers.
1231 See also the hardcopy commands of Dired (@pxref{Misc File Ops})
1232 and the diary (@pxref{Diary Commands}).
1235 @item M-x print-buffer
1236 Print hardcopy of current buffer with page headings containing the file
1237 name and page number.
1238 @item M-x lpr-buffer
1239 Print hardcopy of current buffer without page headings.
1240 @item M-x print-region
1241 Like @code{print-buffer} but print only the current region.
1242 @item M-x lpr-region
1243 Like @code{lpr-buffer} but print only the current region.
1246 @findex print-buffer
1247 @findex print-region
1250 @vindex lpr-switches
1251 The hardcopy commands (aside from the Postscript commands) pass extra
1252 switches to the @code{lpr} program based on the value of the variable
1253 @code{lpr-switches}. Its value should be a list of strings, each string
1254 an option starting with @samp{-}. For example, to specify a line width
1255 of 80 columns for all the printing you do in Emacs, set
1256 @code{lpr-switches} like this:
1259 (setq lpr-switches '("-w80"))
1262 @vindex printer-name
1263 You can specify the printer to use by setting the variable
1264 @code{printer-name}.
1266 @vindex lpr-headers-switches
1267 @vindex lpr-commands
1268 @vindex lpr-add-switches
1269 The variable @code{lpr-command} specifies the name of the printer
1270 program to run; the default value depends on your operating system type.
1271 On most systems, the default is @code{"lpr"}. The variable
1272 @code{lpr-headers-switches} similarly specifies the extra switches to
1273 use to make page headers. The variable @code{lpr-add-switches} controls
1274 whether to supply @samp{-T} and @samp{-J} options (suitable for
1275 @code{lpr}) to the printer program: @code{nil} means don't add them.
1276 @code{lpr-add-switches} should be @code{nil} if your printer program is
1277 not compatible with @code{lpr}.
1279 @node PostScript, PostScript Variables, Hardcopy, Top
1280 @section PostScript Hardcopy
1282 These commands convert buffer contents to PostScript,
1283 either printing it or leaving it in another Emacs buffer.
1286 @item M-x ps-print-buffer
1287 Print hardcopy of the current buffer in PostScript form.
1288 @item M-x ps-print-region
1289 Print hardcopy of the current region in PostScript form.
1290 @item M-x ps-print-buffer-with-faces
1291 Print hardcopy of the current buffer in PostScript form, showing the
1292 faces used in the text by means of PostScript features.
1293 @item M-x ps-print-region-with-faces
1294 Print hardcopy of the current region in PostScript form, showing the
1295 faces used in the text.
1296 @item M-x ps-spool-buffer
1297 Generate PostScript for the current buffer text.
1298 @item M-x ps-spool-region
1299 Generate PostScript for the current region.
1300 @item M-x ps-spool-buffer-with-faces
1301 Generate PostScript for the current buffer, showing the faces used.
1302 @item M-x ps-spool-region-with-faces
1303 Generate PostScript for the current region, showing the faces used.
1305 Generates/prints PostScript for the current buffer as if handwritten.
1308 @findex ps-print-region
1309 @findex ps-print-buffer
1310 @findex ps-print-region-with-faces
1311 @findex ps-print-buffer-with-faces
1312 The PostScript commands, @code{ps-print-buffer} and
1313 @code{ps-print-region}, print buffer contents in PostScript form. One
1314 command prints the entire buffer; the other, just the region. The
1315 corresponding @samp{-with-faces} commands,
1316 @code{ps-print-buffer-with-faces} and @code{ps-print-region-with-faces},
1317 use PostScript features to show the faces (fonts and colors) in the text
1318 properties of the text being printed.
1320 If you are using a color display, you can print a buffer of program
1321 code with color highlighting by turning on Font-Lock mode in that
1322 buffer, and using @code{ps-print-buffer-with-faces}.
1324 @findex ps-spool-region
1325 @findex ps-spool-buffer
1326 @findex ps-spool-region-with-faces
1327 @findex ps-spool-buffer-with-faces
1328 The commands whose names have @samp{spool} instead of @samp{print}
1329 generate the PostScript output in an Emacs buffer instead of sending
1334 @kbd{M-x handwrite} is more frivolous. It generates a PostScript
1335 rendition of the current buffer as a cursive handwritten document. It
1336 can be customized in group @code{handwrite}.
1339 The following section describes variables for customizing these commands.
1342 @node PostScript Variables, Sorting, PostScript, Top
1343 @section Variables for PostScript Hardcopy
1345 @vindex ps-lpr-command
1346 @vindex ps-lpr-switches
1347 @vindex ps-printer-name
1348 All the PostScript hardcopy commands use the variables
1349 @code{ps-lpr-command} and @code{ps-lpr-switches} to specify how to print
1350 the output. @code{ps-lpr-command} specifies the command name to run,
1351 @code{ps-lpr-switches} specifies command line options to use, and
1352 @code{ps-printer-name} specifies the printer. If you don't set the
1353 first two variables yourself, they take their initial values from
1354 @code{lpr-command} and @code{lpr-switches}. If @code{ps-printer-name}
1355 is @code{nil}, @code{printer-name} is used.
1357 @vindex ps-print-header
1358 @vindex ps-print-color-p
1359 The variable @code{ps-print-header} controls whether these commands
1360 add header lines to each page---set it to @code{nil} to turn headers
1361 off. You can turn off color processing by setting
1362 @code{ps-print-color-p} to @code{nil}.
1364 @vindex ps-paper-type
1365 @vindex ps-page-dimensions-database
1366 The variable @code{ps-paper-type} specifies which size of paper to
1367 format for; legitimate values include @code{a4}, @code{a3},
1368 @code{a4small}, @code{b4}, @code{b5}, @code{executive}, @code{ledger},
1369 @code{legal}, @code{letter}, @code{letter-small}, @code{statement},
1370 @code{tabloid}. The default is @code{letter}. You can define
1371 additional paper sizes by changing the variable
1372 @code{ps-page-dimensions-database}.
1374 @vindex ps-landscape-mode
1375 The variable @code{ps-landscape-mode} specifies the orientation of
1376 printing on the page. The default is @code{nil}, which stands for
1377 ``portrait'' mode. Any non-@code{nil} value specifies ``landscape''
1380 @vindex ps-number-of-columns
1381 The variable @code{ps-number-of-columns} specifies the number of
1382 columns; it takes effect in both landscape and portrait mode. The
1385 @vindex ps-font-family
1386 @vindex ps-font-size
1387 @vindex ps-font-info-database
1388 The variable @code{ps-font-family} specifies which font family to use
1389 for printing ordinary text. Legitimate values include @code{Courier},
1390 @code{Helvetica}, @code{NewCenturySchlbk}, @code{Palatino} and
1391 @code{Times}. The variable @code{ps-font-size} specifies the size of
1392 the font for ordinary text. It defaults to 8.5 points.
1394 Many other customization variables for these commands are defined and
1395 described in the Lisp file @file{ps-print.el}.
1397 @node Sorting, Narrowing, PostScript Variables, Top
1398 @section Sorting Text
1401 Emacs provides several commands for sorting text in the buffer. All
1402 operate on the contents of the region (the text between point and the
1403 mark). They divide the text of the region into many @dfn{sort records},
1404 identify a @dfn{sort key} for each record, and then reorder the records
1405 into the order determined by the sort keys. The records are ordered so
1406 that their keys are in alphabetical order, or, for numeric sorting, in
1407 numeric order. In alphabetic sorting, all upper-case letters `A' through
1408 `Z' come before lower-case `a', in accord with the ASCII character
1411 The various sort commands differ in how they divide the text into sort
1412 records and in which part of each record is used as the sort key. Most of
1413 the commands make each line a separate sort record, but some commands use
1414 paragraphs or pages as sort records. Most of the sort commands use each
1415 entire sort record as its own sort key, but some use only a portion of the
1416 record as the sort key.
1419 @findex sort-paragraphs
1422 @findex sort-numeric-fields
1423 @vindex sort-numeric-base
1425 @item M-x sort-lines
1426 Divide the region into lines, and sort by comparing the entire
1427 text of a line. A numeric argument means sort into descending order.
1429 @item M-x sort-paragraphs
1430 Divide the region into paragraphs, and sort by comparing the entire
1431 text of a paragraph (except for leading blank lines). A numeric
1432 argument means sort into descending order.
1434 @item M-x sort-pages
1435 Divide the region into pages, and sort by comparing the entire
1436 text of a page (except for leading blank lines). A numeric
1437 argument means sort into descending order.
1439 @item M-x sort-fields
1440 Divide the region into lines, and sort by comparing the contents of
1441 one field in each line. Fields are defined as separated by
1442 whitespace, so the first run of consecutive non-whitespace characters
1443 in a line constitutes field 1, the second such run constitutes field
1446 Specify which field to sort by with a numeric argument: 1 to sort by
1447 field 1, etc. A negative argument means count fields from the right
1448 instead of from the left; thus, minus 1 means sort by the last field.
1449 If several lines have identical contents in the field being sorted, they
1450 keep same relative order that they had in the original buffer.
1452 @item M-x sort-numeric-fields
1453 Like @kbd{M-x sort-fields} except the specified field is converted
1454 to an integer for each line, and the numbers are compared. @samp{10}
1455 comes before @samp{2} when considered as text, but after it when
1456 considered as a number. By default, numbers are interpreted according
1457 to @code{sort-numeric-base}, but numbers beginning with @samp{0x} or
1458 @samp{0} are interpreted as hexadecimal and octal, respectively.
1460 @item M-x sort-columns
1461 Like @kbd{M-x sort-fields} except that the text within each line
1462 used for comparison comes from a fixed range of columns. See below
1465 @item M-x reverse-region
1466 Reverse the order of the lines in the region. This is useful for
1467 sorting into descending order by fields or columns, since those sort
1468 commands do not have a feature for doing that.
1471 For example, if the buffer contains this:
1474 On systems where clash detection (locking of files being edited) is
1475 implemented, Emacs also checks the first time you modify a buffer
1476 whether the file has changed on disk since it was last visited or
1477 saved. If it has, you are asked to confirm that you want to change
1482 applying @kbd{M-x sort-lines} to the entire buffer produces this:
1485 On systems where clash detection (locking of files being edited) is
1486 implemented, Emacs also checks the first time you modify a buffer
1487 saved. If it has, you are asked to confirm that you want to change
1489 whether the file has changed on disk since it was last visited or
1493 where the upper-case @samp{O} sorts before all lower-case letters. If
1494 you use @kbd{C-u 2 M-x sort-fields} instead, you get this:
1497 implemented, Emacs also checks the first time you modify a buffer
1498 saved. If it has, you are asked to confirm that you want to change
1500 On systems where clash detection (locking of files being edited) is
1501 whether the file has changed on disk since it was last visited or
1505 where the sort keys were @samp{Emacs}, @samp{If}, @samp{buffer},
1506 @samp{systems} and @samp{the}.
1508 @findex sort-columns
1509 @kbd{M-x sort-columns} requires more explanation. You specify the
1510 columns by putting point at one of the columns and the mark at the other
1511 column. Because this means you cannot put point or the mark at the
1512 beginning of the first line of the text you want to sort, this command
1513 uses an unusual definition of `region': all of the line point is in is
1514 considered part of the region, and so is all of the line the mark is in,
1515 as well as all the lines in between.
1517 For example, to sort a table by information found in columns 10 to 15,
1518 you could put the mark on column 10 in the first line of the table, and
1519 point on column 15 in the last line of the table, and then run
1520 @code{sort-columns}. Equivalently, you could run it with the mark on
1521 column 15 in the first line and point on column 10 in the last line.
1523 This can be thought of as sorting the rectangle specified by point and
1524 the mark, except that the text on each line to the left or right of the
1525 rectangle moves along with the text inside the rectangle.
1528 @vindex sort-fold-case
1529 Many of the sort commands ignore case differences when comparing, if
1530 @code{sort-fold-case} is non-@code{nil}.
1532 @node Narrowing, Two-Column, Sorting, Top
1537 @cindex accessible portion
1539 @dfn{Narrowing} means focusing in on some portion of the buffer,
1540 making the rest temporarily inaccessible. The portion which you can
1541 still get to is called the @dfn{accessible portion}. Canceling the
1542 narrowing, which makes the entire buffer once again accessible, is
1543 called @dfn{widening}. The amount of narrowing in effect in a buffer at
1544 any time is called the buffer's @dfn{restriction}.
1546 Narrowing can make it easier to concentrate on a single subroutine or
1547 paragraph by eliminating clutter. It can also be used to restrict the
1548 range of operation of a replace command or repeating keyboard macro.
1553 Narrow down to between point and mark (@code{narrow-to-region}).
1555 Widen to make the entire buffer accessible again (@code{widen}).
1557 Narrow down to the current page (@code{narrow-to-page}).
1559 Narrow down to the current defun (@code{narrow-to-defun}).
1562 When you have narrowed down to a part of the buffer, that part appears
1563 to be all there is. You can't see the rest, you can't move into it
1564 (motion commands won't go outside the accessible part), you can't change
1565 it in any way. However, it is not gone, and if you save the file all
1566 the inaccessible text will be saved. The word @samp{Narrow} appears in
1567 the mode line whenever narrowing is in effect.
1570 @findex narrow-to-region
1571 The primary narrowing command is @kbd{C-x n n} (@code{narrow-to-region}).
1572 It sets the current buffer's restrictions so that the text in the current
1573 region remains accessible but all text before the region or after the region
1574 is inaccessible. Point and mark do not change.
1577 @findex narrow-to-page
1579 @findex narrow-to-defun
1580 Alternatively, use @kbd{C-x n p} (@code{narrow-to-page}) to narrow
1581 down to the current page. @xref{Pages}, for the definition of a page.
1582 @kbd{C-x n d} (@code{narrow-to-defun}) narrows down to the defun
1583 containing point (@pxref{Defuns}).
1587 The way to cancel narrowing is to widen with @kbd{C-x n w}
1588 (@code{widen}). This makes all text in the buffer accessible again.
1590 You can get information on what part of the buffer you are narrowed down
1591 to using the @kbd{C-x =} command. @xref{Position Info}.
1593 Because narrowing can easily confuse users who do not understand it,
1594 @code{narrow-to-region} is normally a disabled command. Attempting to use
1595 this command asks for confirmation and gives you the option of enabling it;
1596 if you enable the command, confirmation will no longer be required for
1597 it. @xref{Disabling}.
1599 @node Two-Column, Editing Binary Files, Narrowing, Top
1600 @section Two-Column Editing
1601 @cindex two-column editing
1602 @cindex splitting columns
1603 @cindex columns, splitting
1605 Two-column mode lets you conveniently edit two side-by-side columns of
1606 text. It uses two side-by-side windows, each showing its own
1609 There are three ways to enter two-column mode:
1612 @item @kbd{@key{F2} 2} or @kbd{C-x 6 2}
1615 @findex 2C-two-columns
1616 Enter two-column mode with the current buffer on the left, and on the
1617 right, a buffer whose name is based on the current buffer's name
1618 (@code{2C-two-columns}). If the right-hand buffer doesn't already
1619 exist, it starts out empty; the current buffer's contents are not
1622 This command is appropriate when the current buffer is empty or contains
1623 just one column and you want to add another column.
1625 @item @kbd{@key{F2} s} or @kbd{C-x 6 s}
1629 Split the current buffer, which contains two-column text, into two
1630 buffers, and display them side by side (@code{2C-split}). The current
1631 buffer becomes the left-hand buffer, but the text in the right-hand
1632 column is moved into the right-hand buffer. The current column
1633 specifies the split point. Splitting starts with the current line and
1634 continues to the end of the buffer.
1636 This command is appropriate when you have a buffer that already contains
1637 two-column text, and you wish to separate the columns temporarily.
1639 @item @kbd{@key{F2} b @var{buffer} @key{RET}}
1640 @itemx @kbd{C-x 6 b @var{buffer} @key{RET}}
1643 @findex 2C-associate-buffer
1644 Enter two-column mode using the current buffer as the left-hand buffer,
1645 and using buffer @var{buffer} as the right-hand buffer
1646 (@code{2C-associate-buffer}).
1649 @kbd{@key{F2} s} or @kbd{C-x 6 s} looks for a column separator, which
1650 is a string that appears on each line between the two columns. You can
1651 specify the width of the separator with a numeric argument to
1652 @kbd{@key{F2} s}; that many characters, before point, constitute the
1653 separator string. By default, the width is 1, so the column separator
1654 is the character before point.
1656 When a line has the separator at the proper place, @kbd{@key{F2} s}
1657 puts the text after the separator into the right-hand buffer, and
1658 deletes the separator. Lines that don't have the column separator at
1659 the proper place remain unsplit; they stay in the left-hand buffer, and
1660 the right-hand buffer gets an empty line to correspond. (This is the
1661 way to write a line that ``spans both columns while in two-column
1662 mode'': write it in the left-hand buffer, and put an empty line in the
1668 The command @kbd{C-x 6 @key{RET}} or @kbd{@key{F2} @key{RET}}
1669 (@code{2C-newline}) inserts a newline in each of the two buffers at
1670 corresponding positions. This is the easiest way to add a new line to
1671 the two-column text while editing it in split buffers.
1676 When you have edited both buffers as you wish, merge them with
1677 @kbd{@key{F2} 1} or @kbd{C-x 6 1} (@code{2C-merge}). This copies the
1678 text from the right-hand buffer as a second column in the other buffer.
1679 To go back to two-column editing, use @kbd{@key{F2} s}.
1683 @findex 2C-dissociate
1684 Use @kbd{@key{F2} d} or @kbd{C-x 6 d} to dissociate the two buffers,
1685 leaving each as it stands (@code{2C-dissociate}). If the other buffer,
1686 the one not current when you type @kbd{@key{F2} d}, is empty,
1687 @kbd{@key{F2} d} kills it.
1689 @node Editing Binary Files, Saving Emacs Sessions, Two-Column, Top
1690 @section Editing Binary Files
1694 @cindex editing binary files
1695 There is a special major mode for editing binary files: Hexl mode. To
1696 use it, use @kbd{M-x hexl-find-file} instead of @kbd{C-x C-f} to visit
1697 the file. This command converts the file's contents to hexadecimal and
1698 lets you edit the translation. When you save the file, it is converted
1699 automatically back to binary.
1701 You can also use @kbd{M-x hexl-mode} to translate an existing buffer
1702 into hex. This is useful if you visit a file normally and then discover
1703 it is a binary file.
1705 Ordinary text characters overwrite in Hexl mode. This is to reduce
1706 the risk of accidentally spoiling the alignment of data in the file.
1707 There are special commands for insertion. Here is a list of the
1708 commands of Hexl mode:
1710 @c I don't think individual index entries for these commands are useful--RMS.
1713 Insert a byte with a code typed in decimal.
1716 Insert a byte with a code typed in octal.
1719 Insert a byte with a code typed in hex.
1722 Move to the beginning of a 1k-byte ``page.''
1725 Move to the end of a 1k-byte ``page.''
1728 Move to an address specified in hex.
1731 Move to an address specified in decimal.
1734 Leave Hexl mode, going back to the major mode this buffer had before you
1735 invoked @code{hexl-mode}.
1738 @node Saving Emacs Sessions, Recursive Edit, Editing Binary Files, Top
1739 @section Saving Emacs Sessions
1740 @cindex saving sessions
1743 You can use the Desktop library to save the state of Emacs from one
1744 session to another. Saving the state means that Emacs starts up with
1745 the same set of buffers, major modes, buffer positions, and so on that
1746 the previous Emacs session had.
1748 @vindex desktop-enable
1749 To use Desktop, you should use the Customization buffer (@pxref{Easy
1750 Customization}) to set @code{desktop-enable} to a non-@code{nil} value,
1751 or add these lines at the end of your @file{.emacs} file:
1754 (desktop-load-default)
1759 @findex desktop-save
1760 The first time you save the state of the Emacs session, you must do it
1761 manually, with the command @kbd{M-x desktop-save}. Once you have done
1762 that, exiting Emacs will save the state again---not only the present
1763 Emacs session, but also subsequent sessions. You can also save the
1764 state at any time, without exiting Emacs, by typing @kbd{M-x
1765 desktop-save} again.
1767 In order for Emacs to recover the state from a previous session, you
1768 must start it with the same current directory as you used when you
1769 started the previous session. This is because @code{desktop-read} looks
1770 in the current directory for the file to read. This means that you can
1771 have separate saved sessions in different directories; the directory in
1772 which you start Emacs will control which saved session to use.
1774 @vindex desktop-files-not-to-save
1775 The variable @code{desktop-files-not-to-save} controls which files are
1776 excluded from state saving. Its value is a regular expression that
1777 matches the files to exclude. By default, remote (ftp-accessed) files
1778 are excluded; this is because visiting them again in the subsequent
1779 session would be slow. If you want to include these files in state
1780 saving, set @code{desktop-files-not-to-save} to @code{"^$"}.
1781 @xref{Remote Files}.
1785 @findex toggle-save-place
1786 There is a simpler mechanism provided by Saveplace library which records
1787 your position in each file when you kill its buffer (or kill Emacs), and
1788 jumps to the same position when you visit the file again (even in
1789 another Emacs session). Use @key{M-x toggle-save-place} to turn on
1790 place-saving in a given file. Customize the option @code{save-place} to
1791 turn it on for all files in each session.
1793 @node Recursive Edit, Emulation, Saving Emacs Sessions, Top
1794 @section Recursive Editing Levels
1795 @cindex recursive editing level
1796 @cindex editing level, recursive
1798 A @dfn{recursive edit} is a situation in which you are using Emacs
1799 commands to perform arbitrary editing while in the middle of another
1800 Emacs command. For example, when you type @kbd{C-r} inside of a
1801 @code{query-replace}, you enter a recursive edit in which you can change
1802 the current buffer. On exiting from the recursive edit, you go back to
1803 the @code{query-replace}.
1806 @findex exit-recursive-edit
1807 @cindex exiting recursive edit
1808 @dfn{Exiting} the recursive edit means returning to the unfinished
1809 command, which continues execution. The command to exit is @kbd{C-M-c}
1810 (@code{exit-recursive-edit}).
1812 You can also @dfn{abort} the recursive edit. This is like exiting,
1813 but also quits the unfinished command immediately. Use the command
1814 @kbd{C-]} (@code{abort-recursive-edit}) to do this. @xref{Quitting}.
1816 The mode line shows you when you are in a recursive edit by displaying
1817 square brackets around the parentheses that always surround the major and
1818 minor mode names. Every window's mode line shows this, in the same way,
1819 since being in a recursive edit is true of Emacs as a whole rather than
1820 any particular window or buffer.
1822 It is possible to be in recursive edits within recursive edits. For
1823 example, after typing @kbd{C-r} in a @code{query-replace}, you may type a
1824 command that enters the debugger. This begins a recursive editing level
1825 for the debugger, within the recursive editing level for @kbd{C-r}.
1826 Mode lines display a pair of square brackets for each recursive editing
1827 level currently in progress.
1829 Exiting the inner recursive edit (such as, with the debugger @kbd{c}
1830 command) resumes the command running in the next level up. When that
1831 command finishes, you can then use @kbd{C-M-c} to exit another recursive
1832 editing level, and so on. Exiting applies to the innermost level only.
1833 Aborting also gets out of only one level of recursive edit; it returns
1834 immediately to the command level of the previous recursive edit. If you
1835 wish, you can then abort the next recursive editing level.
1837 Alternatively, the command @kbd{M-x top-level} aborts all levels of
1838 recursive edits, returning immediately to the top-level command reader.
1840 The text being edited inside the recursive edit need not be the same text
1841 that you were editing at top level. It depends on what the recursive edit
1842 is for. If the command that invokes the recursive edit selects a different
1843 buffer first, that is the buffer you will edit recursively. In any case,
1844 you can switch buffers within the recursive edit in the normal manner (as
1845 long as the buffer-switching keys have not been rebound). You could
1846 probably do all the rest of your editing inside the recursive edit,
1847 visiting files and all. But this could have surprising effects (such as
1848 stack overflow) from time to time. So remember to exit or abort the
1849 recursive edit when you no longer need it.
1851 In general, we try to minimize the use of recursive editing levels in
1852 GNU Emacs. This is because they constrain you to ``go back'' in a
1853 particular order---from the innermost level toward the top level. When
1854 possible, we present different activities in separate buffers so that
1855 you can switch between them as you please. Some commands switch to a
1856 new major mode which provides a command to switch back. These
1857 approaches give you more flexibility to go back to unfinished tasks in
1858 the order you choose.
1860 @node Emulation, Hyperlinking, Recursive Edit, Top
1862 @cindex emulating other editors
1863 @cindex other editors
1868 @cindex PC keybindings
1869 @cindex scrolling all windows
1871 @cindex Motif keybindings
1872 @cindex Macintosh keybindings
1875 GNU Emacs can be programmed to emulate (more or less) most other
1876 editors. Standard facilities can emulate these:
1879 @item CRiSP/Brief (PC editor)
1881 @vindex crisp-override-meta-x
1882 @findex scroll-all-mode
1884 @cindex Brief emulation
1886 You can turn on keybindings to emulate the CRiSP/Brief editor with
1887 @kbd{M-x crisp-mode}. Note that this rebinds @kbd{M-x} to exit Emacs
1888 unless you change the user option @code{crisp-override-meta-x}. You can
1889 also use the command @kbd{M-x scroll-all-mode} or set the user option
1890 @code{crisp-load-scroll-all} to emulate CRiSP's scroll-all feature
1891 (scrolling all windows together).
1893 @item EDT (DEC VMS editor)
1894 @findex edt-emulation-on
1895 @findex edt-emulation-off
1896 Turn on EDT emulation with @kbd{M-x edt-emulation-on}. @kbd{M-x
1897 edt-emulation-off} restores normal Emacs command bindings.
1899 Most of the EDT emulation commands are keypad keys, and most standard
1900 Emacs key bindings are still available. The EDT emulation rebindings
1901 are done in the global keymap, so there is no problem switching
1902 buffers or major modes while in EDT emulation.
1905 @findex pc-bindings-mode
1906 @cindex `PC' key bindings
1907 The command @kbd{M-x pc-bindings-mode} sets up certain key bindings for
1908 `PC compatibility'---what people are often used to on PCs---as follows:
1909 @kbd{Delete} and its variants) delete forward instead of backward,
1910 @kbd{C-Backspace} kills backward a word (as @kbd{C-Delete} normally
1911 would), @kbd{M-Backspace} does undo, @kbd{Home} and @kbd{End} move to
1912 beginning and end of line, @kbd{C-Home} and @kbd{C-End} move to
1913 beginning and end of buffer and @kbd{C-Escape} does @code{list-buffers}.
1915 @item PC Selection mode
1916 @findex pc-selection-mode
1917 @cindex PC Selection minor mode
1918 @cindex mode, PC selection
1919 @cindex selection, `PC'
1920 The command @kbd{M-x pc-selction-mode} turns on a global minor mode
1921 which emulates the mark, copy, cut and paste
1922 look-and-feel of Motif programs (which is the same as the Macintosh GUI
1923 and MS-Windows). It makes the keybindings of PC mode and also modifies
1924 the bindings of the cursor keys and the @kbd{next}, @kbd{prior},
1925 @kbd{home} and @kbd{end} keys. It does not provide the full set of CUA
1926 keybindings---the fundamental Emacs keys @kbd{C-c}, @kbd{C-v} and
1927 @kbd{C-x} are not rebound.
1929 The standard keys for moving around (@kbd{right}, @kbd{left}, @kbd{up},
1930 @kbd{down}, @kbd{home}, @kbd{end}, @kbd{prior}, @kbd{next}, called
1931 ``move-keys'') will always de-activate the mark. Using @kbd{Shift}
1932 together with the ``move keys'' activates the region over which they
1933 move. The copy, cut and paste functions (as in many other programs)
1934 operate on the active region, bound to @kbd{C-insert}, @kbd{S-delete}
1935 and @kbd{S-insert} respectively.
1937 The @code{s-region} package provides similar, but less complete,
1940 @item TPU (DEC VMS editor)
1943 @kbd{M-x tpu-edt-on} turns on emulation of the TPU editor emulating EDT.
1945 @item vi (Berkeley editor)
1947 Viper is the newest emulator for vi. It implements several levels of
1948 emulation; level 1 is closest to vi itself, while level 5 departs
1949 somewhat from strict emulation to take advantage of the capabilities of
1950 Emacs. To invoke Viper, type @kbd{M-x viper-mode}; it will guide you
1951 the rest of the way and ask for the emulation level. @inforef{Top,
1954 @item vi (another emulator)
1956 @kbd{M-x vi-mode} enters a major mode that replaces the previously
1957 established major mode. All of the vi commands that, in real vi, enter
1958 ``input'' mode are programmed instead to return to the previous major
1959 mode. Thus, ordinary Emacs serves as vi's ``input'' mode.
1961 Because vi emulation works through major modes, it does not work
1962 to switch buffers during emulation. Return to normal Emacs first.
1964 If you plan to use vi emulation much, you probably want to bind a key
1965 to the @code{vi-mode} command.
1967 @item vi (alternate emulator)
1969 @kbd{M-x vip-mode} invokes another vi emulator, said to resemble real vi
1970 more thoroughly than @kbd{M-x vi-mode}. ``Input'' mode in this emulator
1971 is changed from ordinary Emacs so you can use @key{ESC} to go back to
1972 emulated vi command mode. To get from emulated vi command mode back to
1973 ordinary Emacs, type @kbd{C-z}.
1975 This emulation does not work through major modes, and it is possible
1976 to switch buffers in various ways within the emulator. It is not
1977 so necessary to assign a key to the command @code{vip-mode} as
1978 it is with @code{vi-mode} because terminating insert mode does
1981 @inforef{Top, VIP, vip}, for full information.
1983 @item WordStar (old wordprocessor)
1984 @findex wordstar-mode
1985 @kbd{M-x wordstar-mode} provides a major mode with WordStar-like
1989 @node Hyperlinking, Dissociated Press, Emulation, Top
1990 @section Hyperlinking and Navigation Features
1992 @cindex hyperlinking
1995 Various modes documented elsewhere have hypertext features whereby you
1996 can follow links, usually with @kbd{mouse-2} or @kbd{RET} on the text of
1997 the link. Info mode, Help mode and the Dired-like modes are examples.
1998 The Tags facility links between uses and definitions in source files,
1999 see @ref{Tags}. Imenu provides navigation amongst items indexed in the
2000 current buffer, see @ref{Imenu}. Info-lookup provides mode-specific
2001 lookup of definitions in Info indexes, see @ref{Documentation}.
2002 Speedbar maintains a frame in which links to files, and locations in
2003 files are displayed, see @ref{Speedbar}.
2005 Other non-mode-specific facilities described in this section enable
2006 following links from the current buffer in a context-sensitive fashion.
2009 * Browse-URL:: Following URLs.
2010 * Goto-address:: Activating URLs.
2011 * FFAP:: Finding files etc. at point.
2012 * Find-func:: Finding function and variable definitions.
2016 @subsection Following URLs
2017 @cindex World Wide Web
2020 @findex browse-url-at-point
2021 @findex browse-url-at-mouse
2026 @item M-x browse-url @key{RET} @var{url} @key{ret}
2027 Load a URL into a Web browser.
2030 The Browse-URL package provides facilities for following URLs specifying
2031 links on the World Wide Web. Usually this works by invoking a web
2032 browser but you can, for instance, arrange to invoke @code{compose-mail}
2033 from @samp{mailto:} URLs. Packages such as Gnus may make active links
2034 from URLs themselves. Otherwise you can use @kbd{M-x browse-url} to
2035 follow a link, defaulting to the URL at point. Other commands are
2036 available which you might like to bind to keys, such as
2037 @code{browse-url-at-point} and @code{browse-url-at-mouse}.
2039 @vindex browse-url-browser-function
2040 You can customize Browse-URL's behaviour via various options in the
2041 @code{browse-url} Customize group, particularly
2042 @code{browse-url-browser-function}. You can invoke actions dependent on
2043 the type of URL by defining @code{browse-url-browser-function} as an
2044 association list. The package's commentary available via @kbd{C-h p}
2045 provides more information. Packages with facilities for following URLs
2046 should use Browse-URL, so customizing options in the @code{browse-url}
2047 group should be sufficient to determine how they all work in that
2051 @subsection Activating URLs
2052 @findex goto-address
2053 @cindex Goto-address
2054 @cindex URLs, activating
2057 @item M-x goto-address
2058 Activate URLs and e-mail addresses in the current buffer.
2061 You can arrange to activate URLs in any buffer with @kbd{M-x
2062 goto-address}. It may be useful to add @code{goto-address} to hooks
2063 invoked when buffers are displayed in particular modes.
2064 @code{rmail-show-message-hook} is the appropriate hook if you use Rmail,
2065 or @code{mh-show-mode-hook} if you use MH.
2068 @subsection Finding Files and URLs at Point
2070 @findex find-file-at-point
2072 @findex ffap-dired-at-point
2077 @cindex finding file at point
2080 @item M-x ffap @key{RET} @var{filename} @key{RET}
2081 Find @var{filename}, guessing a default from text around point.
2083 Search buffer for next file or URL, and run `ffap'. With single prefix
2084 arg, search backwards, with double arg wrap search forwards, with triple
2085 arg wrap search backwards.
2087 Put up a menu of files and URLs mentioned in current buffer and try to
2088 fetch the selected one.
2089 @item M-x ffap-dired-at-point
2090 Start Dired, defaulting to file at point.
2093 The command @kbd{M-x find-file-at-point} (or @kbd{M-x ffap}) can be used
2094 as a replacement for @kbd{M-x find-file}. With a prefix argument it
2095 behaves as @kbd{M-x find-file}. Otherwise it tries to guess a default
2096 file or URL from the text around point. In the case of a URL, it will
2097 invoke @code{browse-url} rather than finding a file. This is useful for
2098 following references in mail or news buffers, @file{README}s,
2099 @file{MANIFEST}s, and so on. The @samp{ffap} package's
2100 commentary available via @kbd{C-h p} and the @code{ffap} Custom group
2103 @cindex FFAP minor mode
2105 You can turn on FFAP minor mode to make the following key bindings and
2106 to install hooks for using @code{ffap} in Rmail, Gnus and VM article
2111 @kindex C-x C-f @r{(FFAP)}
2112 @kbd{find-file-at-point};
2114 @kindex C-x 4 f @r{(FFAP)}
2115 @code{ffap-other-window}, analagous to @kbd{M-x find-file-other-window};
2117 @kindex C-x 5 f @r{(FFAP)}
2118 @code{ffap-other-frame}, analagous to @kbd{M-x find-file-other-frame};
2120 @kindex C-x d @r{(FFAP)}
2121 @code{ffap-dired-at-point}, analogous to @kbd{M-x dired};
2123 @kindex S-mouse-3 @r{(FFAP)}
2124 @code{ffap-at-mouse} finds the file guessed from text around the position
2127 @kindex C-S-mouse-3 @r{(FFAP)}
2128 @code{ffap-menu} puts up a selectable menu of files and URLs mentioned in
2133 @subsection Finding Function and Variable Definitions
2134 @findex find-function
2135 @findex find-function-on-key
2136 @findex find-variable
2137 @cindex examples of Lisp functions
2138 @cindex Lisp examples
2140 @cindex Lisp definitions
2141 @cindex definitions, locating in sources
2145 @item M-x find-function @key{RET} @var{function} @key{RET}
2146 Find the definition of the @var{function} at point.
2147 @item M-x find-variable @key{RET} @var{variable} @key{RET}
2148 Find the definition of the @var{variable} at point.
2149 @item M-x find-function-on-key @var{key}
2150 Find the definition of the function that @var{key} invokes.
2153 The Find-func package provides convenient facilities for finding the
2154 definitions of Emacs Lisp functions and variables. It has a somewhat
2155 similar function to the Tags facility (@pxref{Tags}) but uses Emacs's
2156 introspective facilities which maintain information about loaded
2157 libraries. In contrast to Tags, it only works for functions and
2158 variables with definitions which are already loaded but it relates to
2159 the code actually running and doesn't require maintaining tags files.
2161 You need to have the Lisp source (@samp{.el}) files available on your
2162 load path along with the compiled (@samp{.elc}) versions for this to
2163 work. You can use compressed source files if you turn on
2164 @code{auto-compression-mode}.
2166 The commands available include @kbd{M-x find-function} to find the
2167 definition of a named function, @kbd{find-function-on-key} to find the
2168 definition of the function bound to a key and @kbd{find-variable} to
2169 find a variable's definition. These only work for things defined in
2170 Lisp source files, not primitive functions or variables defined
2171 primitively in the Emacs layer implemented in C.
2173 Find-func is useful for finding examples of how to do things if you want
2174 to write an Emacs Lisp extension similar to some existing function.
2176 @node Dissociated Press, Amusements, Hyperlinking, Top
2177 @section Dissociated Press
2179 @findex dissociated-press
2180 @kbd{M-x dissociated-press} is a command for scrambling a file of text
2181 either word by word or character by character. Starting from a buffer of
2182 straight English, it produces extremely amusing output. The input comes
2183 from the current Emacs buffer. Dissociated Press writes its output in a
2184 buffer named @samp{*Dissociation*}, and redisplays that buffer after every
2185 couple of lines (approximately) so you can read the output as it comes out.
2187 Dissociated Press asks every so often whether to continue generating
2188 output. Answer @kbd{n} to stop it. You can also stop at any time by
2189 typing @kbd{C-g}. The dissociation output remains in the
2190 @samp{*Dissociation*} buffer for you to copy elsewhere if you wish.
2192 @cindex presidentagon
2193 Dissociated Press operates by jumping at random from one point in the
2194 buffer to another. In order to produce plausible output rather than
2195 gibberish, it insists on a certain amount of overlap between the end of
2196 one run of consecutive words or characters and the start of the next.
2197 That is, if it has just printed out `president' and then decides to jump
2198 to a different point in the file, it might spot the `ent' in `pentagon'
2199 and continue from there, producing `presidentagon'.@footnote{This
2200 dissociword actually appeared during the Vietnam War, when it was very
2201 appropriate.} Long sample texts produce the best results.
2203 @cindex againformation
2204 A positive argument to @kbd{M-x dissociated-press} tells it to operate
2205 character by character, and specifies the number of overlap characters. A
2206 negative argument tells it to operate word by word and specifies the number
2207 of overlap words. In this mode, whole words are treated as the elements to
2208 be permuted, rather than characters. No argument is equivalent to an
2209 argument of two. For your againformation, the output goes only into the
2210 buffer @samp{*Dissociation*}. The buffer you start with is not changed.
2212 @cindex Markov chain
2214 @cindex techniquitous
2215 Dissociated Press produces nearly the same results as a Markov chain
2216 based on a frequency table constructed from the sample text. It is,
2217 however, an independent, ignoriginal invention. Dissociated Press
2218 techniquitously copies several consecutive characters from the sample
2219 between random choices, whereas a Markov chain would choose randomly for
2220 each word or character. This makes for more plausible sounding results,
2227 @cindex developediment
2229 It is a mustatement that too much use of Dissociated Press can be a
2230 developediment to your real work. Sometimes to the point of outragedy.
2231 And keep dissociwords out of your documentation, if you want it to be well
2232 userenced and properbose. Have fun. Your buggestions are welcome.
2234 @node Amusements, Customization, Dissociated Press, Top
2235 @section Other Amusements
2240 @cindex tower of Hanoi
2242 If you are a little bit bored, you can try @kbd{M-x hanoi}. If you are
2243 considerably bored, give it a numeric argument. If you are very very
2244 bored, try an argument of 9. Sit back and watch.
2247 If you want a little more personal involvement, try @kbd{M-x gomoku},
2248 which plays the game Go Moku with you.
2254 @kbd{M-x blackbox}, @kbd{M-x mpuz} and @kbd{M-x 5x5} are kinds of puzzles.
2255 @code{blackbox} challenges you to determine the location of objects
2256 inside a box by tomography. @code{mpuz} displays a multiplication
2257 puzzle with letters standing for digits in a code that you must
2258 guess---to guess a value, type a letter and then the digit you think it
2259 stands for. The aim of @code{5x5} is to fill in all the squares.
2263 @cindex cryptanalysis
2264 @kbd{M-x decipher} helps you to cryptanalyze a buffer which is encrypted
2265 in a simple monoalphabetic substitution cipher.
2268 @kbd{M-x dunnet} runs an adventure-style exploration game, which is
2269 a bigger sort of puzzle.
2272 @cindex landmark game
2273 @kbd{M-x lm} runs a relatively non-participatory game in which a robot
2274 attempts to maneuver towards a tree at the center of the window based on
2275 unique olfactory cues from each of the four directions.
2279 @kbd{M-x life} runs Conway's `Life' cellular automaton.
2281 @findex morse-region
2282 @findex unmorse-region
2284 @cindex --/---/.-./.../.
2285 @kbd{M-x morse-region} converts text in a region to Morse code and
2286 @kbd{M-x unmorse-region} converts it back. No cause for remorse.
2290 @kbd{M-x pong} plays an implementation of the game Pong, bouncing the
2291 ball off opposing bats.
2295 @kbd{M-x solitaire} plays a game of solitaire in which you jump pegs
2298 @findex studlify-region
2300 @kbd{M-x studlify-region} studlify-cases the region, that is
2303 M-x stUdlIfY-RegioN stUdlIfY-CaSeS thE region.
2308 @kbd{M-x tetris} runs an implementation of the well-known Tetris game.
2311 Likewise, @kbd{M-x snake} provides an implementation of Snake.
2313 When you are frustrated, try the famous Eliza program. Just do
2314 @kbd{M-x doctor}. End each input by typing @key{RET} twice.
2317 When you are feeling strange, type @kbd{M-x yow}.
2320 The command @kbd{M-x zone} plays games with the display when Emacs is