1 @c This is part of the Emacs manual.
2 @c Copyright (C) 1985, 86, 87, 93, 94, 95, 97, 2000, 2001
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
310 to an Emacs buffer named @samp{*shell*} or run a shell inside a terminal
313 There is a shell implemented entirely in Emacs, documented in a separate
314 manual. @xref{Top,Eshell,Eshell, eshell, Eshell: The Emacs Shell}.
317 @item M-! @var{cmd} @key{RET}
318 Run the shell command line @var{cmd} and display the output
319 (@code{shell-command}).
320 @item M-| @var{cmd} @key{RET}
321 Run the shell command line @var{cmd} with region contents as input;
322 optionally replace the region with the output
323 (@code{shell-command-on-region}).
325 Run a subshell with input and output through an Emacs buffer.
326 You can then give commands interactively.
328 Run a subshell with input and output through an Emacs buffer.
329 You can then give commands interactively.
330 Full terminal emulation is available.
333 Start the Emacs shell.
337 * Single Shell:: How to run one shell command and return.
338 * Interactive Shell:: Permanent shell taking input via Emacs.
339 * Shell Mode:: Special Emacs commands used with permanent shell.
340 * History: Shell History. Repeating previous commands in a shell buffer.
341 * Directory Tracking:: Keeping track when the subshell changes directory.
342 * Options: Shell Options. Options for customizing Shell mode.
343 * Terminal emulator:: An Emacs window as a terminal emulator.
344 * Term Mode:: Special Emacs commands used in Term mode.
345 * Paging in Term:: Paging in the terminal emulator.
346 * Remote Host:: Connecting to another computer.
350 @subsection Single Shell Commands
353 @findex shell-command
354 @kbd{M-!} (@code{shell-command}) reads a line of text using the
355 minibuffer and executes it as a shell command in a subshell made just
356 for that command. Standard input for the command comes from the null
357 device. If the shell command produces any output, the output appears
358 either in the echo area (if it is short), or in an Emacs buffer named
359 @samp{*Shell Command Output*}, which is displayed in another window
360 but not selected (if the output is long).
362 For instance, one way to decompress a file @file{foo.gz} from Emacs
363 is to type @kbd{M-! gunzip foo.gz @key{RET}}. That shell command
364 normally creates the file @file{foo} and produces no terminal output.
366 A numeric argument, as in @kbd{M-1 M-!}, says to insert terminal
367 output into the current buffer instead of a separate buffer. It puts
368 point before the output, and sets the mark after the output. For
369 instance, @kbd{M-1 M-! gunzip < foo.gz @key{RET}} would insert the
370 uncompressed equivalent of @file{foo.gz} into the current buffer.
372 If the shell command line ends in @samp{&}, it runs asynchronously.
373 For a synchronous shell command, @code{shell-command} returns the
374 command's exit status (0 means success), when it is called from a Lisp
375 program. You do not get any status information for an asynchronous
376 command, since it hasn't finished yet.
379 @findex shell-command-on-region
380 @kbd{M-|} (@code{shell-command-on-region}) is like @kbd{M-!} but
381 passes the contents of the region as the standard input to the shell
382 command, instead of no input. If a numeric argument is used, meaning
383 insert the output in the current buffer, then the old region is deleted
384 first and the output replaces it as the contents of the region. It
385 returns the command's exit status when it is called from a Lisp program.
387 One use for @kbd{M-|} is to run @code{uudecode}. For instance, if
388 the buffer contains uuencoded text, type @kbd{C-x h M-| uudecode
389 @key{RET}} to feed the entire buffer contents to the @code{uudecode}
390 program. That program will ignore everything except the encoded text,
391 and will store the decoded output into the file whose name is
392 specified in the encoded text.
394 @vindex shell-file-name
396 Both @kbd{M-!} and @kbd{M-|} use @code{shell-file-name} to specify the
397 shell to use. This variable is initialized based on your @env{SHELL}
398 environment variable when Emacs is started. If the file name does not
399 specify a directory, the directories in the list @code{exec-path} are
400 searched; this list is initialized based on the environment variable
401 @env{PATH} when Emacs is started. Your @file{.emacs} file can override
402 either or both of these default initializations.@refill
404 Both @kbd{M-!} and @kbd{M-|} wait for the shell command to complete.
405 To stop waiting, type @kbd{C-g} to quit; that terminates the shell
406 command with the signal @code{SIGINT}---the same signal that @kbd{C-c}
407 normally generates in the shell. Emacs waits until the command actually
408 terminates. If the shell command doesn't stop (because it ignores the
409 @code{SIGINT} signal), type @kbd{C-g} again; this sends the command a
410 @code{SIGKILL} signal which is impossible to ignore.
412 To specify a coding system for @kbd{M-!} or @kbd{M-|}, use the command
413 @kbd{C-x @key{RET} c} immediately beforehand. @xref{Specify Coding}.
415 @vindex shell-command-default-error-buffer
416 Error output from the command is normally intermixed with the regular
417 output. If you set the variable
418 @code{shell-command-default-error-buffer} to a string, which is a buffer
419 name, error output is inserted before point in the buffer of that name.
421 @node Interactive Shell
422 @subsection Interactive Inferior Shell
425 To run a subshell interactively, putting its typescript in an Emacs
426 buffer, use @kbd{M-x shell}. This creates (or reuses) a buffer named
427 @samp{*shell*} and runs a subshell with input coming from and output going
428 to that buffer. That is to say, any ``terminal output'' from the subshell
429 goes into the buffer, advancing point, and any ``terminal input'' for
430 the subshell comes from text in the buffer. To give input to the subshell,
431 go to the end of the buffer and type the input, terminated by @key{RET}.
433 Emacs does not wait for the subshell to do anything. You can switch
434 windows or buffers and edit them while the shell is waiting, or while it is
435 running a command. Output from the subshell waits until Emacs has time to
436 process it; this happens whenever Emacs is waiting for keyboard input or
439 @cindex @code{comint-highlight-input} face
440 @cindex @code{comint-highlight-prompt} face
441 Input lines, once you submit them, are displayed using the face
442 @code{comint-highlight-input}, and prompts are displayed using the
443 face @code{comint-highlight-prompt}. This makes it easier to see
444 previous input lines in the buffer. @xref{Faces}.
446 To make multiple subshells invoke @kbd{M-x shell} with a prefix
447 argument (e.g. @kbd{C-u M-x shell}), which will cause it to prompt for
448 a buffer name, and create (or reuse) a subshell in that buffer. All
449 subshells in different buffers run independently and in parallel.
451 @vindex explicit-shell-file-name
452 @cindex @env{ESHELL} environment variable
453 @cindex @env{SHELL} environment variable
454 The file name used to load the subshell is the value of the variable
455 @code{explicit-shell-file-name}, if that is non-@code{nil}. Otherwise,
456 the environment variable @env{ESHELL} is used, or the environment
457 variable @env{SHELL} if there is no @env{ESHELL}. If the file name
458 specified is relative, the directories in the list @code{exec-path} are
459 searched; this list is initialized based on the environment variable
460 @env{PATH} when Emacs is started. Your @file{.emacs} file can override
461 either or both of these default initializations.
463 Emacs sends the new shell the contents of the file
464 @file{~/.emacs_@var{shellname}} as input, if it exists, where
465 @var{shellname} is the name of the file that the shell was loaded
466 from. For example, if you use bash, the file sent to it is
467 @file{~/.emacs_bash}.
469 To specify a coding system for the shell, you can use the command
470 @kbd{C-x @key{RET} c} immediately before @kbd{M-x shell}. You can also
471 specify a coding system after starting the shell by using @kbd{C-x
472 @key{RET} p} in the shell buffer. @xref{Specify Coding}.
474 Emacs defines the environment variable @env{EMACS} in the subshell,
475 with value @code{t}. A shell script can check this variable to
476 determine whether it has been run from an Emacs subshell.
479 @subsection Shell Mode
483 Shell buffers use Shell mode, which defines several special keys
484 attached to the @kbd{C-c} prefix. They are chosen to resemble the usual
485 editing and job control characters present in shells that are not under
486 Emacs, except that you must type @kbd{C-c} first. Here is a complete list
487 of the special key bindings of Shell mode:
491 @kindex RET @r{(Shell mode)}
492 @findex comint-send-input
493 At end of buffer send line as input; otherwise, copy current line to
494 end of buffer and send it (@code{comint-send-input}). When a line is
495 copied, any prompt at the beginning of the line (text output by
496 programs preceding your input) is omitted. (See also the variable
497 @code{comint-use-prompt-regexp-instead-of-fields}.)
500 @kindex TAB @r{(Shell mode)}
501 @findex comint-dynamic-complete
502 Complete the command name or file name before point in the shell buffer
503 (@code{comint-dynamic-complete}). @key{TAB} also completes history
504 references (@pxref{History References}) and environment variable names.
506 @vindex shell-completion-fignore
507 @vindex comint-completion-fignore
508 The variable @code{shell-completion-fignore} specifies a list of file
509 name extensions to ignore in Shell mode completion. The default
510 setting is @code{nil}, but some users prefer @code{("~" "#" "%")} to
511 ignore file names ending in @samp{~}, @samp{#} or @samp{%}. Other
512 related Comint modes use the variable @code{comint-completion-fignore}
516 @kindex M-? @r{(Shell mode)}
517 @findex comint-dynamic-list-filename@dots{}
518 Display temporarily a list of the possible completions of the file name
519 before point in the shell buffer
520 (@code{comint-dynamic-list-filename-completions}).
523 @kindex C-d @r{(Shell mode)}
524 @findex comint-delchar-or-maybe-eof
525 Either delete a character or send @sc{eof}
526 (@code{comint-delchar-or-maybe-eof}). Typed at the end of the shell
527 buffer, @kbd{C-d} sends @sc{eof} to the subshell. Typed at any other
528 position in the buffer, @kbd{C-d} deletes a character as usual.
531 @kindex C-c C-a @r{(Shell mode)}
532 @findex comint-bol-or-process-mark
533 Move to the beginning of the line, but after the prompt if any
534 (@code{comint-bol-or-process-mark}). If you repeat this command twice
535 in a row, the second time it moves back to the process mark, which is
536 the beginning of the input that you have not yet sent to the subshell.
537 (Normally that is the same place---the end of the prompt on this
538 line---but after @kbd{C-c @key{SPC}} the process mark may be in a
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-delete-output
582 Delete the last batch of output from a shell command
583 (@code{comint-delete-output}). This is useful if a shell command spews
584 out lots of output that just gets in the way. This command used to be
585 called @code{comint-kill-output}.
588 @kindex C-c C-s @r{(Shell mode)}
589 @findex comint-write-output
590 Write the last batch of output from a shell command to a file
591 (@code{comint-write-output}). With a prefix argument, the file is
592 appended to instead. Any prompt at the end of the output is not
597 @kindex C-c C-r @r{(Shell mode)}
598 @kindex C-M-l @r{(Shell mode)}
599 @findex comint-show-output
600 Scroll to display the beginning of the last batch of output at the top
601 of the window; also move the cursor there (@code{comint-show-output}).
604 @kindex C-c C-e @r{(Shell mode)}
605 @findex comint-show-maximum-output
606 Scroll to put the end of the buffer at the bottom of the window
607 (@code{comint-show-maximum-output}).
610 @kindex C-c C-f @r{(Shell mode)}
611 @findex shell-forward-command
612 @vindex shell-command-regexp
613 Move forward across one shell command, but not beyond the current line
614 (@code{shell-forward-command}). The variable @code{shell-command-regexp}
615 specifies how to recognize the end of a command.
618 @kindex C-c C-b @r{(Shell mode)}
619 @findex shell-backward-command
620 Move backward across one shell command, but not beyond the current line
621 (@code{shell-backward-command}).
624 @kindex C-c C-l @r{(Shell mode)}
625 @findex comint-dynamic-list-input-ring
626 Display the buffer's history of shell commands in another window
627 (@code{comint-dynamic-list-input-ring}).
630 Ask the shell what its current directory is, so that Emacs can agree
633 @item M-x send-invisible @key{RET} @var{text} @key{RET}
634 @findex send-invisible
635 Send @var{text} as input to the shell, after reading it without
636 echoing. This is useful when a shell command runs a program that asks
639 Alternatively, you can arrange for Emacs to notice password prompts
640 and turn off echoing for them, as follows:
643 (add-hook 'comint-output-filter-functions
644 'comint-watch-for-password-prompt)
647 @item M-x comint-continue-subjob
648 @findex comint-continue-subjob
649 Continue the shell process. This is useful if you accidentally suspend
650 the shell process.@footnote{You should not suspend the shell process.
651 Suspending a subjob of the shell is a completely different matter---that
652 is normal practice, but you must use the shell to continue the subjob;
653 this command won't do it.}
655 @item M-x comint-strip-ctrl-m
656 @findex comint-strip-ctrl-m
657 Discard all control-M characters from the current group of shell output.
658 The most convenient way to use this command is to make it run
659 automatically when you get output from the subshell. To do that,
660 evaluate this Lisp expression:
663 (add-hook 'comint-output-filter-functions
664 'comint-strip-ctrl-m)
667 @item M-x comint-truncate-buffer
668 @findex comint-truncate-buffer
669 This command truncates the shell buffer to a certain maximum number of
670 lines, specified by the variable @code{comint-buffer-maximum-size}.
671 Here's how to do this automatically each time you get output from the
675 (add-hook 'comint-output-filter-functions
676 'comint-truncate-buffer)
680 Shell mode also customizes the paragraph commands so that only shell
681 prompts start new paragraphs. Thus, a paragraph consists of an input
682 command plus the output that follows it in the buffer.
686 Shell mode is a derivative of Comint mode, a general-purpose mode for
687 communicating with interactive subprocesses. Most of the features of
688 Shell mode actually come from Comint mode, as you can see from the
689 command names listed above. The special features of Shell mode include
690 the directory tracking feature, and a few user commands.
692 Other Emacs features that use variants of Comint mode include GUD
693 (@pxref{Debuggers}) and @kbd{M-x run-lisp} (@pxref{External Lisp}).
696 You can use @kbd{M-x comint-run} to execute any program of your choice
697 in a subprocess using unmodified Comint mode---without the
698 specializations of Shell mode.
701 @subsection Shell Command History
703 Shell buffers support three ways of repeating earlier commands. You
704 can use the same keys used in the minibuffer; these work much as they do
705 in the minibuffer, inserting text from prior commands while point
706 remains always at the end of the buffer. You can move through the
707 buffer to previous inputs in their original place, then resubmit them or
708 copy them to the end. Or you can use a @samp{!}-style history
712 * Ring: Shell Ring. Fetching commands from the history list.
713 * Copy: Shell History Copying. Moving to a command and then copying it.
714 * History References:: Expanding @samp{!}-style history references.
718 @subsubsection Shell History Ring
721 @findex comint-previous-input
722 @kindex M-p @r{(Shell mode)}
724 Fetch the next earlier old shell command.
726 @kindex M-n @r{(Shell mode)}
727 @findex comint-next-input
729 Fetch the next later old shell command.
731 @kindex M-r @r{(Shell mode)}
732 @kindex M-s @r{(Shell mode)}
733 @findex comint-previous-matching-input
734 @findex comint-next-matching-input
735 @item M-r @var{regexp} @key{RET}
736 @itemx M-s @var{regexp} @key{RET}
737 Search backwards or forwards for old shell commands that match @var{regexp}.
739 @item C-c C-x @r{(Shell mode)}
740 @findex comint-get-next-from-history
741 Fetch the next subsequent command from the history.
744 Shell buffers provide a history of previously entered shell commands. To
745 reuse shell commands from the history, use the editing commands @kbd{M-p},
746 @kbd{M-n}, @kbd{M-r} and @kbd{M-s}. These work just like the minibuffer
747 history commands except that they operate on the text at the end of the
748 shell buffer, where you would normally insert text to send to the shell.
750 @kbd{M-p} fetches an earlier shell command to the end of the shell buffer.
751 Successive use of @kbd{M-p} fetches successively earlier shell commands,
752 each replacing any text that was already present as potential shell input.
753 @kbd{M-n} does likewise except that it finds successively more recent shell
754 commands from the buffer.
756 The history search commands @kbd{M-r} and @kbd{M-s} read a regular
757 expression and search through the history for a matching command. Aside
758 from the choice of which command to fetch, they work just like @kbd{M-p}
759 and @kbd{M-r}. If you enter an empty regexp, these commands reuse the
760 same regexp used last time.
762 When you find the previous input you want, you can resubmit it by
763 typing @key{RET}, or you can edit it first and then resubmit it if you
766 Often it is useful to reexecute several successive shell commands that
767 were previously executed in sequence. To do this, first find and
768 reexecute the first command of the sequence. Then type @kbd{C-c C-x};
769 that will fetch the following command---the one that follows the command
770 you just repeated. Then type @key{RET} to reexecute this command. You
771 can reexecute several successive commands by typing @kbd{C-c C-x
772 @key{RET}} over and over.
774 These commands get the text of previous shell commands from a special
775 history list, not from the shell buffer itself. Thus, editing the shell
776 buffer, or even killing large parts of it, does not affect the history
777 that these commands access.
779 @vindex shell-input-ring-file-name
780 Some shells store their command histories in files so that you can
781 refer to previous commands from previous shell sessions. Emacs reads
782 the command history file for your chosen shell, to initialize its own
783 command history. The file name is @file{~/.bash_history} for bash,
784 @file{~/.sh_history} for ksh, and @file{~/.history} for other shells.
786 @node Shell History Copying
787 @subsubsection Shell History Copying
790 @kindex C-c C-p @r{(Shell mode)}
791 @findex comint-previous-prompt
793 Move point to the previous prompt (@code{comint-previous-prompt}).
795 @kindex C-c C-n @r{(Shell mode)}
796 @findex comint-next-prompt
798 Move point to the following prompt (@code{comint-next-prompt}).
800 @kindex C-c RET @r{(Shell mode)}
801 @findex comint-copy-old-input
803 Copy the input command which point is in, inserting the copy at the end
804 of the buffer (@code{comint-copy-old-input}). This is useful if you
805 move point back to a previous command. After you copy the command, you
806 can submit the copy as input with @key{RET}. If you wish, you can
807 edit the copy before resubmitting it.
810 Moving to a previous input and then copying it with @kbd{C-c
811 @key{RET}} produces the same results---the same buffer contents---that
812 you would get by using @kbd{M-p} enough times to fetch that previous
813 input from the history list. However, @kbd{C-c @key{RET}} copies the
814 text from the buffer, which can be different from what is in the history
815 list if you edit the input text in the buffer after it has been sent.
817 @node History References
818 @subsubsection Shell History References
819 @cindex history reference
821 Various shells including csh and bash support @dfn{history
822 references} that begin with @samp{!} and @samp{^}. Shell mode
823 recognizes these constructs, and can perform the history substitution
826 If you insert a history reference and type @key{TAB}, this searches
827 the input history for a matching command, performs substitution if
828 necessary, and places the result in the buffer in place of the history
829 reference. For example, you can fetch the most recent command
830 beginning with @samp{mv} with @kbd{! m v @key{TAB}}. You can edit the
831 command if you wish, and then resubmit the command to the shell by
834 @vindex comint-input-autoexpand
835 @findex comint-magic-space
836 Shell mode can optionally expand history references in the buffer
837 when you send them to the shell. To request this, set the variable
838 @code{comint-input-autoexpand} to @code{input}. You can make
839 @key{SPC} perform history expansion by binding @key{SPC} to the
840 command @code{comint-magic-space}.
842 @vindex shell-prompt-pattern
843 @vindex comint-prompt-regexp
844 @vindex comint-use-prompt-regexp-instead-of-fields
845 @cindex prompt, shell
846 Shell mode recognizes history references when they follow a prompt.
847 Normally, any text output by a program at the beginning of an input
848 line is considered a prompt. However, if the variable
849 @code{comint-use-prompt-regexp-instead-of-fields} is non-@code{nil},
850 then Comint mode uses a regular expression to recognize prompts. In
851 general, the variable @code{comint-prompt-regexp} specifies the
852 regular expression; Shell mode uses the variable
853 @code{shell-prompt-pattern} to set up @code{comint-prompt-regexp} in
856 @node Directory Tracking
857 @subsection Directory Tracking
858 @cindex directory tracking
860 @vindex shell-pushd-regexp
861 @vindex shell-popd-regexp
862 @vindex shell-cd-regexp
863 Shell mode keeps track of @samp{cd}, @samp{pushd} and @samp{popd}
864 commands given to the inferior shell, so it can keep the
865 @samp{*shell*} buffer's default directory the same as the shell's
866 working directory. It recognizes these commands syntactically, by
867 examining lines of input that are sent.
869 If you use aliases for these commands, you can tell Emacs to
870 recognize them also. For example, if the value of the variable
871 @code{shell-pushd-regexp} matches the beginning of a shell command
872 line, that line is regarded as a @code{pushd} command. Change this
873 variable when you add aliases for @samp{pushd}. Likewise,
874 @code{shell-popd-regexp} and @code{shell-cd-regexp} are used to
875 recognize commands with the meaning of @samp{popd} and @samp{cd}.
876 These commands are recognized only at the beginning of a shell command
879 @ignore @c This seems to have been deleted long ago.
880 @vindex shell-set-directory-error-hook
881 If Emacs gets an error while trying to handle what it believes is a
882 @samp{cd}, @samp{pushd} or @samp{popd} command, it runs the hook
883 @code{shell-set-directory-error-hook} (@pxref{Hooks}).
887 If Emacs gets confused about changes in the current directory of the
888 subshell, use the command @kbd{M-x dirs} to ask the shell what its
889 current directory is. This command works for shells that support the
890 most common command syntax; it may not work for unusual shells.
892 @findex dirtrack-mode
893 You can also use @kbd{M-x dirtrack-mode} to enable (or disable) an
894 alternative and more aggressive method of tracking changes in the
898 @subsection Shell Mode Options
900 @vindex comint-scroll-to-bottom-on-input
901 If the variable @code{comint-scroll-to-bottom-on-input} is
902 non-@code{nil}, insertion and yank commands scroll the selected window
903 to the bottom before inserting.
905 @vindex comint-scroll-show-maximum-output
906 If @code{comint-scroll-show-maximum-output} is non-@code{nil}, then
907 scrolling due to arrival of output tries to place the last line of text
908 at the bottom line of the window, so as to show as much useful text as
909 possible. (This mimics the scrolling behavior of many terminals.)
910 The default is @code{nil}.
912 @vindex comint-scroll-to-bottom-on-output
913 By setting @code{comint-scroll-to-bottom-on-output}, you can opt for
914 having point jump to the end of the buffer whenever output arrives---no
915 matter where in the buffer point was before. If the value is
916 @code{this}, point jumps in the selected window. If the value is
917 @code{all}, point jumps in each window that shows the comint buffer. If
918 the value is @code{other}, point jumps in all nonselected windows that
919 show the current buffer. The default value is @code{nil}, which means
920 point does not jump to the end.
922 @vindex comint-input-ignoredups
923 The variable @code{comint-input-ignoredups} controls whether successive
924 identical inputs are stored in the input history. A non-@code{nil}
925 value means to omit an input that is the same as the previous input.
926 The default is @code{nil}, which means to store each input even if it is
927 equal to the previous input.
929 @vindex comint-completion-addsuffix
930 @vindex comint-completion-recexact
931 @vindex comint-completion-autolist
932 Three variables customize file name completion. The variable
933 @code{comint-completion-addsuffix} controls whether completion inserts a
934 space or a slash to indicate a fully completed file or directory name
935 (non-@code{nil} means do insert a space or slash).
936 @code{comint-completion-recexact}, if non-@code{nil}, directs @key{TAB}
937 to choose the shortest possible completion if the usual Emacs completion
938 algorithm cannot add even a single character.
939 @code{comint-completion-autolist}, if non-@code{nil}, says to list all
940 the possible completions whenever completion is not exact.
942 @vindex shell-completion-execonly
943 Command completion normally considers only executable files.
944 If you set @code{shell-completion-execonly} to @code{nil},
945 it considers nonexecutable files as well.
947 @findex shell-pushd-tohome
948 @findex shell-pushd-dextract
949 @findex shell-pushd-dunique
950 You can configure the behavior of @samp{pushd}. Variables control
951 whether @samp{pushd} behaves like @samp{cd} if no argument is given
952 (@code{shell-pushd-tohome}), pop rather than rotate with a numeric
953 argument (@code{shell-pushd-dextract}), and only add directories to the
954 directory stack if they are not already on it
955 (@code{shell-pushd-dunique}). The values you choose should match the
956 underlying shell, of course.
958 @node Terminal emulator
959 @subsection Emacs Terminal Emulator
962 To run a subshell in a terminal emulator, putting its typescript in
963 an Emacs buffer, use @kbd{M-x term}. This creates (or reuses) a
964 buffer named @samp{*terminal*}, and runs a subshell with input coming
965 from your keyboard, and output going to that buffer.
967 The terminal emulator uses Term mode, which has two input modes. In
968 line mode, Term basically acts like Shell mode; see @ref{Shell Mode}.
970 In char mode, each character is sent directly to the inferior
971 subshell, as ``terminal input.'' Any ``echoing'' of your input is the
972 responsibility of the subshell. The sole exception is the terminal
973 escape character, which by default is @kbd{C-c} (@pxref{Term Mode}).
974 Any ``terminal output'' from the subshell goes into the buffer,
977 Some programs (such as Emacs itself) need to control the appearance
978 on the terminal screen in detail. They do this by sending special
979 control codes. The exact control codes needed vary from terminal to
980 terminal, but nowadays most terminals and terminal emulators
981 (including @code{xterm}) understand the ANSI-standard (VT100-style)
982 escape sequences. Term mode recognizes these escape sequences, and
983 handles each one appropriately, changing the buffer so that the
984 appearance of the window matches what it would be on a real terminal.
985 You can actually run Emacs inside an Emacs Term window.
987 The file name used to load the subshell is determined the same way
988 as for Shell mode. To make multiple terminal emulators, rename the
989 buffer @samp{*terminal*} to something different using @kbd{M-x
990 rename-uniquely}, just as with Shell mode.
992 Unlike Shell mode, Term mode does not track the current directory by
993 examining your input. But some shells can tell Term what the current
994 directory is. This is done automatically by @code{bash} version 1.15
998 @subsection Term Mode
1002 The terminal emulator uses Term mode, which has two input modes. In
1003 line mode, Term basically acts like Shell mode; see @ref{Shell Mode}.
1004 In char mode, each character is sent directly to the inferior
1005 subshell, except for the Term escape character, normally @kbd{C-c}.
1007 To switch between line and char mode, use these commands:
1010 @kindex C-c C-k @r{(Term mode)}
1011 @findex term-char-mode
1013 Switch to line mode. Do nothing if already in line mode.
1015 @kindex C-c C-j @r{(Term mode)}
1016 @findex term-line-mode
1018 Switch to char mode. Do nothing if already in char mode.
1021 The following commands are only available in char mode:
1025 Send a literal @key{C-c} to the sub-shell.
1028 A prefix command to access the global @key{C-x} commands conveniently.
1029 For example, @kbd{C-c C-x o} invokes the global binding of
1030 @kbd{C-x o}, which is normally @samp{other-window}.
1033 @node Paging in Term
1034 @subsection Page-At-A-Time Output
1035 @cindex page-at-a-time
1037 Term mode has a page-at-a-time feature. When enabled it makes
1038 output pause at the end of each screenful.
1041 @kindex C-c C-q @r{(Term mode)}
1042 @findex term-pager-toggle
1044 Toggle the page-at-a-time feature. This command works in both line
1045 and char modes. When page-at-a-time is enabled, the mode-line
1046 displays the word @samp{page}.
1049 With page-at-a-time enabled, whenever Term receives more than a
1050 screenful of output since your last input, it pauses, displaying
1051 @samp{**MORE**} in the mode-line. Type @key{SPC} to display the next
1052 screenful of output. Type @kbd{?} to see your other options. The
1053 interface is similar to the Unix @code{more} program.
1056 @subsection Remote Host Shell
1058 @cindex connecting to remote host
1062 You can login to a remote computer, using whatever commands you
1063 would from a regular terminal (e.g.@: using the @code{telnet} or
1064 @code{rlogin} commands), from a Term window.
1066 A program that asks you for a password will normally suppress
1067 echoing of the password, so the password will not show up in the
1068 buffer. This will happen just as if you were using a real terminal,
1069 if the buffer is in char mode. If it is in line mode, the password is
1070 temporarily visible, but will be erased when you hit return. (This
1071 happens automatically; there is no special password processing.)
1073 When you log in to a different machine, you need to specify the type
1074 of terminal your using. Terminal types @samp{ansi} or @samp{vt100}
1075 will work on most systems.
1077 @c If you are talking to a Bourne-compatible
1078 @c shell, and your system understands the @env{TERMCAP} variable,
1079 @c you can use the command @kbd{M-x shell-send-termcap}, which
1080 @c sends a string specifying the terminal type and size.
1081 @c (This command is also useful after the window has changed size.)
1083 @c You can of course run @samp{gdb} on that remote computer. One useful
1084 @c trick: If you invoke gdb with the @code{--fullname} option,
1085 @c it will send special commands to Emacs that will cause Emacs to
1086 @c pop up the source files you're debugging. This will work
1087 @c whether or not gdb is running on a different computer than Emacs,
1088 @c as long as Emacs can access the source files specified by gdb.
1091 You cannot log into to a remote computer using the Shell mode.
1092 @c (This will change when Shell is re-written to use Term.)
1093 Instead, Emacs provides two commands for logging in to another computer
1094 and communicating with it through an Emacs buffer using Comint mode:
1097 @item M-x telnet @key{RET} @var{hostname} @key{RET}
1098 Set up a Telnet connection to the computer named @var{hostname}.
1099 @item M-x rlogin @key{RET} @var{hostname} @key{RET}
1100 Set up an Rlogin connection to the computer named @var{hostname}.
1104 Use @kbd{M-x telnet} to set up a Telnet connection to another
1105 computer. (Telnet is the standard Internet protocol for remote login.)
1106 It reads the host name of the other computer as an argument with the
1107 minibuffer. Once the connection is established, talking to the other
1108 computer works like talking to a subshell: you can edit input with the
1109 usual Emacs commands, and send it a line at a time by typing @key{RET}.
1110 The output is inserted in the Telnet buffer interspersed with the input.
1113 @vindex rlogin-explicit-args
1114 Use @kbd{M-x rlogin} to set up an Rlogin connection. Rlogin is
1115 another remote login communication protocol, essentially much like the
1116 Telnet protocol but incompatible with it, and supported only by certain
1117 systems. Rlogin's advantages are that you can arrange not to have to
1118 give your user name and password when communicating between two machines
1119 you frequently use, and that you can make an 8-bit-clean connection.
1120 (To do that in Emacs, set @code{rlogin-explicit-args} to @code{("-8")}
1121 before you run Rlogin.)
1123 @kbd{M-x rlogin} sets up the default file directory of the Emacs
1124 buffer to access the remote host via FTP (@pxref{File Names}), and it
1125 tracks the shell commands that change the current directory, just like
1128 @findex rlogin-directory-tracking-mode
1129 There are two ways of doing directory tracking in an Rlogin
1130 buffer---either with remote directory names
1131 @file{/@var{host}:@var{dir}/} or with local names (that works if the
1132 ``remote'' machine shares file systems with your machine of origin).
1133 You can use the command @code{rlogin-directory-tracking-mode} to switch
1134 modes. No argument means use remote directory names, a positive
1135 argument means use local names, and a negative argument means turn
1136 off directory tracking.
1140 @node Emacs Server, Hardcopy, Shell, Top
1141 @section Using Emacs as a Server
1143 @cindex Emacs as a server
1144 @cindex server, using Emacs as
1145 @cindex @env{EDITOR} environment variable
1147 Various programs such as @code{mail} can invoke your choice of editor
1148 to edit a particular piece of text, such as a message that you are
1149 sending. By convention, most of these programs use the environment
1150 variable @env{EDITOR} to specify which editor to run. If you set
1151 @env{EDITOR} to @samp{emacs}, they invoke Emacs---but in an
1152 inconvenient fashion, by starting a new, separate Emacs process. This
1153 is inconvenient because it takes time and because the new Emacs process
1154 doesn't share the buffers in the existing Emacs process.
1156 You can arrange to use your existing Emacs process as the editor for
1157 programs like @code{mail} by using the Emacs client and Emacs server
1158 programs. Here is how.
1160 @cindex @env{TEXEDIT} environment variable
1161 First, the preparation. Within Emacs, call the function
1162 @code{server-start}. (Your @file{.emacs} file can do this automatically
1163 if you add the expression @code{(server-start)} to it.) Then, outside
1164 Emacs, set the @env{EDITOR} environment variable to @samp{emacsclient}.
1165 (Note that some programs use a different environment variable; for
1166 example, to make @TeX{} use @samp{emacsclient}, you should set the
1167 @env{TEXEDIT} environment variable to @samp{emacsclient +%d %s}.)
1171 Then, whenever any program invokes your specified @env{EDITOR}
1172 program, the effect is to send a message to your principal Emacs telling
1173 it to visit a file. (That's what the program @code{emacsclient} does.)
1174 Emacs displays the buffer immediately and you can immediately begin
1177 When you've finished editing that buffer, type @kbd{C-x #}
1178 (@code{server-edit}). This saves the file and sends a message back to
1179 the @code{emacsclient} program telling it to exit. The programs that
1180 use @env{EDITOR} wait for the ``editor'' (actually, @code{emacsclient})
1181 to exit. @kbd{C-x #} also checks for other pending external requests
1182 to edit various files, and selects the next such file.
1184 You can switch to a server buffer manually if you wish; you don't
1185 have to arrive at it with @kbd{C-x #}. But @kbd{C-x #} is the way to
1186 say that you are ``finished'' with one.
1188 @vindex server-kill-new-buffers
1189 @vindex server-temp-file-regexp
1190 Finishing with a server buffer also kills the buffer, unless it
1191 already existed in the Emacs session before the server asked to create
1192 it. However, if you set @code{server-kill-new-buffers} to @code{nil},
1193 then a different criterion is used: finishing with a server buffer
1194 kills it if the file name matches the regular expression
1195 @code{server-temp-file-regexp}. This is set up to distinguish certain
1196 ``temporary'' files.
1198 @vindex server-window
1199 If you set the variable @code{server-window} to a window or a frame,
1200 @kbd{C-x #} displays the server buffer in that window or in that frame.
1202 While @code{mail} or another application is waiting for
1203 @code{emacsclient} to finish, @code{emacsclient} does not read terminal
1204 input. So the terminal that @code{mail} was using is effectively
1205 blocked for the duration. In order to edit with your principal Emacs,
1206 you need to be able to use it without using that terminal. There are
1207 three ways to do this:
1211 Using a window system, run @code{mail} and the principal Emacs in two
1212 separate windows. While @code{mail} is waiting for @code{emacsclient},
1213 the window where it was running is blocked, but you can use Emacs by
1217 Using virtual terminals, run @code{mail} in one virtual terminal
1218 and run Emacs in another.
1221 Use Shell mode or Term mode in Emacs to run the other program such as
1222 @code{mail}; then, @code{emacsclient} blocks only the subshell under
1223 Emacs, and you can still use Emacs to edit the file.
1226 If you run @code{emacsclient} with the option @samp{--no-wait}, it
1227 returns immediately without waiting for you to ``finish'' the buffer
1228 in Emacs. Note that server buffers created in this way are not killed
1229 automatically when you finish with them.
1232 * Invoking emacsclient::
1235 @node Invoking emacsclient,, Emacs Server, Emacs Server
1236 @section Invoking @code{emacsclient}
1238 To run the @code{emacsclient} program, specify file names as arguments,
1239 and optionally line numbers as well. Do it like this:
1242 emacsclient @r{@{}@r{[}+@var{line}@r{]} @var{filename}@r{@}}@dots{}
1246 This tells Emacs to visit each of the specified files; if you specify a
1247 line number for a certain file, Emacs moves to that line in the file.
1249 Ordinarily, @code{emacsclient} does not return until you use the
1250 @kbd{C-x #} command on each of these buffers. When that happens,
1251 Emacs sends a message to the @code{emacsclient} program telling it to
1254 But if you use the option @samp{-n} or @samp{--no-wait} when running
1255 @code{emacsclient}, then it returns immediately. (You can take as
1256 long as you like to edit the files in Emacs.)
1258 The option @samp{--alternate-editor=@var{command}} is useful when
1259 running @code{emacsclient} in a script. It specifies a command to run
1260 if @code{emacsclient} fails to contact Emacs. For example, the
1261 following setting for the @var{EDITOR} environment variable will
1262 always give an editor, even if Emacs is not running:
1265 EDITOR="emacsclient --alternate-editor vi +%d %s"
1269 The environment variable @var{ALTERNATE_EDITOR} has the same effect, but
1270 the value of the @samp{--alternate-editor} takes precedence.
1273 Alternatively, the file @file{etc/emacs.bash} defines a bash
1274 function which will communicate with a running Emacs server, or start
1277 @node Hardcopy, PostScript, Emacs Server, Top
1278 @section Hardcopy Output
1281 The Emacs commands for making hardcopy let you print either an entire
1282 buffer or just part of one, either with or without page headers.
1283 See also the hardcopy commands of Dired (@pxref{Misc File Ops})
1284 and the diary (@pxref{Diary Commands}).
1287 @item M-x print-buffer
1288 Print hardcopy of current buffer with page headings containing the file
1289 name and page number.
1290 @item M-x lpr-buffer
1291 Print hardcopy of current buffer without page headings.
1292 @item M-x print-region
1293 Like @code{print-buffer} but print only the current region.
1294 @item M-x lpr-region
1295 Like @code{lpr-buffer} but print only the current region.
1298 @findex print-buffer
1299 @findex print-region
1302 @vindex lpr-switches
1303 The hardcopy commands (aside from the Postscript commands) pass extra
1304 switches to the @code{lpr} program based on the value of the variable
1305 @code{lpr-switches}. Its value should be a list of strings, each string
1306 an option starting with @samp{-}. For example, to specify a line width
1307 of 80 columns for all the printing you do in Emacs, set
1308 @code{lpr-switches} like this:
1311 (setq lpr-switches '("-w80"))
1314 @vindex printer-name
1315 You can specify the printer to use by setting the variable
1316 @code{printer-name}.
1318 @vindex lpr-headers-switches
1319 @vindex lpr-commands
1320 @vindex lpr-add-switches
1321 The variable @code{lpr-command} specifies the name of the printer
1322 program to run; the default value depends on your operating system type.
1323 On most systems, the default is @code{"lpr"}. The variable
1324 @code{lpr-headers-switches} similarly specifies the extra switches to
1325 use to make page headers. The variable @code{lpr-add-switches} controls
1326 whether to supply @samp{-T} and @samp{-J} options (suitable for
1327 @code{lpr}) to the printer program: @code{nil} means don't add them.
1328 @code{lpr-add-switches} should be @code{nil} if your printer program is
1329 not compatible with @code{lpr}.
1331 @node PostScript, PostScript Variables, Hardcopy, Top
1332 @section PostScript Hardcopy
1334 These commands convert buffer contents to PostScript,
1335 either printing it or leaving it in another Emacs buffer.
1338 @item M-x ps-print-buffer
1339 Print hardcopy of the current buffer in PostScript form.
1340 @item M-x ps-print-region
1341 Print hardcopy of the current region in PostScript form.
1342 @item M-x ps-print-buffer-with-faces
1343 Print hardcopy of the current buffer in PostScript form, showing the
1344 faces used in the text by means of PostScript features.
1345 @item M-x ps-print-region-with-faces
1346 Print hardcopy of the current region in PostScript form, showing the
1347 faces used in the text.
1348 @item M-x ps-spool-buffer
1349 Generate PostScript for the current buffer text.
1350 @item M-x ps-spool-region
1351 Generate PostScript for the current region.
1352 @item M-x ps-spool-buffer-with-faces
1353 Generate PostScript for the current buffer, showing the faces used.
1354 @item M-x ps-spool-region-with-faces
1355 Generate PostScript for the current region, showing the faces used.
1357 Generates/prints PostScript for the current buffer as if handwritten.
1360 @findex ps-print-region
1361 @findex ps-print-buffer
1362 @findex ps-print-region-with-faces
1363 @findex ps-print-buffer-with-faces
1364 The PostScript commands, @code{ps-print-buffer} and
1365 @code{ps-print-region}, print buffer contents in PostScript form. One
1366 command prints the entire buffer; the other, just the region. The
1367 corresponding @samp{-with-faces} commands,
1368 @code{ps-print-buffer-with-faces} and @code{ps-print-region-with-faces},
1369 use PostScript features to show the faces (fonts and colors) in the text
1370 properties of the text being printed.
1372 If you are using a color display, you can print a buffer of program
1373 code with color highlighting by turning on Font-Lock mode in that
1374 buffer, and using @code{ps-print-buffer-with-faces}.
1376 @findex ps-spool-region
1377 @findex ps-spool-buffer
1378 @findex ps-spool-region-with-faces
1379 @findex ps-spool-buffer-with-faces
1380 The commands whose names have @samp{spool} instead of @samp{print}
1381 generate the PostScript output in an Emacs buffer instead of sending
1386 @kbd{M-x handwrite} is more frivolous. It generates a PostScript
1387 rendition of the current buffer as a cursive handwritten document. It
1388 can be customized in group @code{handwrite}. This function only
1389 supports ISO 8859-1 characters.
1392 The following section describes variables for customizing these commands.
1395 @node PostScript Variables, Sorting, PostScript, Top
1396 @section Variables for PostScript Hardcopy
1398 @vindex ps-lpr-command
1399 @vindex ps-lpr-switches
1400 @vindex ps-printer-name
1401 All the PostScript hardcopy commands use the variables
1402 @code{ps-lpr-command} and @code{ps-lpr-switches} to specify how to print
1403 the output. @code{ps-lpr-command} specifies the command name to run,
1404 @code{ps-lpr-switches} specifies command line options to use, and
1405 @code{ps-printer-name} specifies the printer. If you don't set the
1406 first two variables yourself, they take their initial values from
1407 @code{lpr-command} and @code{lpr-switches}. If @code{ps-printer-name}
1408 is @code{nil}, @code{printer-name} is used.
1410 @vindex ps-print-header
1411 The variable @code{ps-print-header} controls whether these commands
1412 add header lines to each page---set it to @code{nil} to turn headers
1415 @cindex color emulation on black-and-white printers
1416 @vindex ps-print-color-p
1417 If your printer doesn't support colors, you should turn off color
1418 processing by setting @code{ps-print-color-p} to @code{nil}. By
1419 default, if the display supports colors, Emacs produces hardcopy output
1420 with color information; on black-and-white printers, colors are emulated
1421 with shades of gray. This might produce illegible output, even if your
1422 screen colors only use shades of gray.
1424 @vindex ps-use-face-background
1425 By default, PostScript printing ignores the background colors of the
1426 faces, unless the variable @code{ps-use-face-background} is
1427 non-@code{nil}. This is to avoid unwanted interference with the zebra
1428 stripes and background image/text.
1430 @vindex ps-paper-type
1431 @vindex ps-page-dimensions-database
1432 The variable @code{ps-paper-type} specifies which size of paper to
1433 format for; legitimate values include @code{a4}, @code{a3},
1434 @code{a4small}, @code{b4}, @code{b5}, @code{executive}, @code{ledger},
1435 @code{legal}, @code{letter}, @code{letter-small}, @code{statement},
1436 @code{tabloid}. The default is @code{letter}. You can define
1437 additional paper sizes by changing the variable
1438 @code{ps-page-dimensions-database}.
1440 @vindex ps-landscape-mode
1441 The variable @code{ps-landscape-mode} specifies the orientation of
1442 printing on the page. The default is @code{nil}, which stands for
1443 ``portrait'' mode. Any non-@code{nil} value specifies ``landscape''
1446 @vindex ps-number-of-columns
1447 The variable @code{ps-number-of-columns} specifies the number of
1448 columns; it takes effect in both landscape and portrait mode. The
1451 @vindex ps-font-family
1452 @vindex ps-font-size
1453 @vindex ps-font-info-database
1454 The variable @code{ps-font-family} specifies which font family to use
1455 for printing ordinary text. Legitimate values include @code{Courier},
1456 @code{Helvetica}, @code{NewCenturySchlbk}, @code{Palatino} and
1457 @code{Times}. The variable @code{ps-font-size} specifies the size of
1458 the font for ordinary text. It defaults to 8.5 points.
1460 @vindex ps-multibyte-buffer
1461 @cindex Intlfonts for PostScript printing
1462 @cindex fonts for PostScript printing
1463 Emacs supports more scripts and characters than a typical PostScript
1464 printer. Thus, some of the characters in your buffer might not be
1465 printable using the fonts built into your printer. You can augment
1466 the fonts supplied with the printer with those from the GNU Intlfonts
1467 package, or you can instruct Emacs to use Intlfonts exclusively. The
1468 variable @code{ps-multibyte-buffer} controls this: the default value,
1469 @code{nil}, is appropriate for printing @sc{ascii} and Latin-1
1470 characters; a value of @code{non-latin-printer} is for printers which
1471 have the fonts for @sc{ascii}, Latin-1, Japanese, and Korean
1472 characters built into them. A value of @code{bdf-font} arranges for
1473 the BDF fonts from the Intlfonts package to be used for @emph{all}
1474 characters. Finally, a value of @code{bdf-font-except-latin}
1475 instructs the printer to use built-in fonts for @sc{ascii} and Latin-1
1476 characters, and Intlfonts BDF fonts for the rest.
1478 @vindex bdf-directory-list
1479 To be able to use the BDF fonts, Emacs should know where to find
1480 them. The variable @code{bdf-directory-list} holds the list of
1481 directories where Emacs should look for the fonts; the default value
1482 includes a single directory @file{/usr/local/share/emacs/fonts/bdf}.
1484 Many other customization variables for these commands are defined and
1485 described in the Lisp files @file{ps-print.el} and @file{ps-mule.el}.
1487 @node Sorting, Narrowing, PostScript Variables, Top
1488 @section Sorting Text
1491 Emacs provides several commands for sorting text in the buffer. All
1492 operate on the contents of the region (the text between point and the
1493 mark). They divide the text of the region into many @dfn{sort records},
1494 identify a @dfn{sort key} for each record, and then reorder the records
1495 into the order determined by the sort keys. The records are ordered so
1496 that their keys are in alphabetical order, or, for numeric sorting, in
1497 numeric order. In alphabetic sorting, all upper-case letters `A' through
1498 `Z' come before lower-case `a', in accord with the ASCII character
1501 The various sort commands differ in how they divide the text into sort
1502 records and in which part of each record is used as the sort key. Most of
1503 the commands make each line a separate sort record, but some commands use
1504 paragraphs or pages as sort records. Most of the sort commands use each
1505 entire sort record as its own sort key, but some use only a portion of the
1506 record as the sort key.
1509 @findex sort-paragraphs
1512 @findex sort-numeric-fields
1513 @vindex sort-numeric-base
1515 @item M-x sort-lines
1516 Divide the region into lines, and sort by comparing the entire
1517 text of a line. A numeric argument means sort into descending order.
1519 @item M-x sort-paragraphs
1520 Divide the region into paragraphs, and sort by comparing the entire
1521 text of a paragraph (except for leading blank lines). A numeric
1522 argument means sort into descending order.
1524 @item M-x sort-pages
1525 Divide the region into pages, and sort by comparing the entire
1526 text of a page (except for leading blank lines). A numeric
1527 argument means sort into descending order.
1529 @item M-x sort-fields
1530 Divide the region into lines, and sort by comparing the contents of
1531 one field in each line. Fields are defined as separated by
1532 whitespace, so the first run of consecutive non-whitespace characters
1533 in a line constitutes field 1, the second such run constitutes field
1536 Specify which field to sort by with a numeric argument: 1 to sort by
1537 field 1, etc. A negative argument means count fields from the right
1538 instead of from the left; thus, minus 1 means sort by the last field.
1539 If several lines have identical contents in the field being sorted, they
1540 keep same relative order that they had in the original buffer.
1542 @item M-x sort-numeric-fields
1543 Like @kbd{M-x sort-fields} except the specified field is converted
1544 to an integer for each line, and the numbers are compared. @samp{10}
1545 comes before @samp{2} when considered as text, but after it when
1546 considered as a number. By default, numbers are interpreted according
1547 to @code{sort-numeric-base}, but numbers beginning with @samp{0x} or
1548 @samp{0} are interpreted as hexadecimal and octal, respectively.
1550 @item M-x sort-columns
1551 Like @kbd{M-x sort-fields} except that the text within each line
1552 used for comparison comes from a fixed range of columns. See below
1555 @item M-x reverse-region
1556 Reverse the order of the lines in the region. This is useful for
1557 sorting into descending order by fields or columns, since those sort
1558 commands do not have a feature for doing that.
1561 For example, if the buffer contains this:
1564 On systems where clash detection (locking of files being edited) is
1565 implemented, Emacs also checks the first time you modify a buffer
1566 whether the file has changed on disk since it was last visited or
1567 saved. If it has, you are asked to confirm that you want to change
1572 applying @kbd{M-x sort-lines} to the entire buffer produces this:
1575 On systems where clash detection (locking of files being edited) is
1576 implemented, Emacs also checks the first time you modify a buffer
1577 saved. If it has, you are asked to confirm that you want to change
1579 whether the file has changed on disk since it was last visited or
1583 where the upper-case @samp{O} sorts before all lower-case letters. If
1584 you use @kbd{C-u 2 M-x sort-fields} instead, you get this:
1587 implemented, Emacs also checks the first time you modify a buffer
1588 saved. If it has, you are asked to confirm that you want to change
1590 On systems where clash detection (locking of files being edited) is
1591 whether the file has changed on disk since it was last visited or
1595 where the sort keys were @samp{Emacs}, @samp{If}, @samp{buffer},
1596 @samp{systems} and @samp{the}.
1598 @findex sort-columns
1599 @kbd{M-x sort-columns} requires more explanation. You specify the
1600 columns by putting point at one of the columns and the mark at the other
1601 column. Because this means you cannot put point or the mark at the
1602 beginning of the first line of the text you want to sort, this command
1603 uses an unusual definition of ``region'': all of the line point is in is
1604 considered part of the region, and so is all of the line the mark is in,
1605 as well as all the lines in between.
1607 For example, to sort a table by information found in columns 10 to 15,
1608 you could put the mark on column 10 in the first line of the table, and
1609 point on column 15 in the last line of the table, and then run
1610 @code{sort-columns}. Equivalently, you could run it with the mark on
1611 column 15 in the first line and point on column 10 in the last line.
1613 This can be thought of as sorting the rectangle specified by point and
1614 the mark, except that the text on each line to the left or right of the
1615 rectangle moves along with the text inside the rectangle.
1618 @vindex sort-fold-case
1619 Many of the sort commands ignore case differences when comparing, if
1620 @code{sort-fold-case} is non-@code{nil}.
1622 @node Narrowing, Two-Column, Sorting, Top
1627 @cindex accessible portion
1629 @dfn{Narrowing} means focusing in on some portion of the buffer,
1630 making the rest temporarily inaccessible. The portion which you can
1631 still get to is called the @dfn{accessible portion}. Canceling the
1632 narrowing, which makes the entire buffer once again accessible, is
1633 called @dfn{widening}. The amount of narrowing in effect in a buffer at
1634 any time is called the buffer's @dfn{restriction}.
1636 Narrowing can make it easier to concentrate on a single subroutine or
1637 paragraph by eliminating clutter. It can also be used to restrict the
1638 range of operation of a replace command or repeating keyboard macro.
1643 Narrow down to between point and mark (@code{narrow-to-region}).
1645 Widen to make the entire buffer accessible again (@code{widen}).
1647 Narrow down to the current page (@code{narrow-to-page}).
1649 Narrow down to the current defun (@code{narrow-to-defun}).
1652 When you have narrowed down to a part of the buffer, that part appears
1653 to be all there is. You can't see the rest, you can't move into it
1654 (motion commands won't go outside the accessible part), you can't change
1655 it in any way. However, it is not gone, and if you save the file all
1656 the inaccessible text will be saved. The word @samp{Narrow} appears in
1657 the mode line whenever narrowing is in effect.
1660 @findex narrow-to-region
1661 The primary narrowing command is @kbd{C-x n n} (@code{narrow-to-region}).
1662 It sets the current buffer's restrictions so that the text in the current
1663 region remains accessible but all text before the region or after the region
1664 is inaccessible. Point and mark do not change.
1667 @findex narrow-to-page
1669 @findex narrow-to-defun
1670 Alternatively, use @kbd{C-x n p} (@code{narrow-to-page}) to narrow
1671 down to the current page. @xref{Pages}, for the definition of a page.
1672 @kbd{C-x n d} (@code{narrow-to-defun}) narrows down to the defun
1673 containing point (@pxref{Defuns}).
1677 The way to cancel narrowing is to widen with @kbd{C-x n w}
1678 (@code{widen}). This makes all text in the buffer accessible again.
1680 You can get information on what part of the buffer you are narrowed down
1681 to using the @kbd{C-x =} command. @xref{Position Info}.
1683 Because narrowing can easily confuse users who do not understand it,
1684 @code{narrow-to-region} is normally a disabled command. Attempting to use
1685 this command asks for confirmation and gives you the option of enabling it;
1686 if you enable the command, confirmation will no longer be required for
1687 it. @xref{Disabling}.
1689 @node Two-Column, Editing Binary Files, Narrowing, Top
1690 @section Two-Column Editing
1691 @cindex two-column editing
1692 @cindex splitting columns
1693 @cindex columns, splitting
1695 Two-column mode lets you conveniently edit two side-by-side columns of
1696 text. It uses two side-by-side windows, each showing its own
1699 There are three ways to enter two-column mode:
1702 @item @kbd{@key{F2} 2} or @kbd{C-x 6 2}
1705 @findex 2C-two-columns
1706 Enter two-column mode with the current buffer on the left, and on the
1707 right, a buffer whose name is based on the current buffer's name
1708 (@code{2C-two-columns}). If the right-hand buffer doesn't already
1709 exist, it starts out empty; the current buffer's contents are not
1712 This command is appropriate when the current buffer is empty or contains
1713 just one column and you want to add another column.
1715 @item @kbd{@key{F2} s} or @kbd{C-x 6 s}
1719 Split the current buffer, which contains two-column text, into two
1720 buffers, and display them side by side (@code{2C-split}). The current
1721 buffer becomes the left-hand buffer, but the text in the right-hand
1722 column is moved into the right-hand buffer. The current column
1723 specifies the split point. Splitting starts with the current line and
1724 continues to the end of the buffer.
1726 This command is appropriate when you have a buffer that already contains
1727 two-column text, and you wish to separate the columns temporarily.
1729 @item @kbd{@key{F2} b @var{buffer} @key{RET}}
1730 @itemx @kbd{C-x 6 b @var{buffer} @key{RET}}
1733 @findex 2C-associate-buffer
1734 Enter two-column mode using the current buffer as the left-hand buffer,
1735 and using buffer @var{buffer} as the right-hand buffer
1736 (@code{2C-associate-buffer}).
1739 @kbd{@key{F2} s} or @kbd{C-x 6 s} looks for a column separator, which
1740 is a string that appears on each line between the two columns. You can
1741 specify the width of the separator with a numeric argument to
1742 @kbd{@key{F2} s}; that many characters, before point, constitute the
1743 separator string. By default, the width is 1, so the column separator
1744 is the character before point.
1746 When a line has the separator at the proper place, @kbd{@key{F2} s}
1747 puts the text after the separator into the right-hand buffer, and
1748 deletes the separator. Lines that don't have the column separator at
1749 the proper place remain unsplit; they stay in the left-hand buffer, and
1750 the right-hand buffer gets an empty line to correspond. (This is the
1751 way to write a line that ``spans both columns while in two-column
1752 mode'': write it in the left-hand buffer, and put an empty line in the
1758 The command @kbd{C-x 6 @key{RET}} or @kbd{@key{F2} @key{RET}}
1759 (@code{2C-newline}) inserts a newline in each of the two buffers at
1760 corresponding positions. This is the easiest way to add a new line to
1761 the two-column text while editing it in split buffers.
1766 When you have edited both buffers as you wish, merge them with
1767 @kbd{@key{F2} 1} or @kbd{C-x 6 1} (@code{2C-merge}). This copies the
1768 text from the right-hand buffer as a second column in the other buffer.
1769 To go back to two-column editing, use @kbd{@key{F2} s}.
1773 @findex 2C-dissociate
1774 Use @kbd{@key{F2} d} or @kbd{C-x 6 d} to dissociate the two buffers,
1775 leaving each as it stands (@code{2C-dissociate}). If the other buffer,
1776 the one not current when you type @kbd{@key{F2} d}, is empty,
1777 @kbd{@key{F2} d} kills it.
1779 @node Editing Binary Files, Saving Emacs Sessions, Two-Column, Top
1780 @section Editing Binary Files
1784 @cindex editing binary files
1786 There is a special major mode for editing binary files: Hexl mode. To
1787 use it, use @kbd{M-x hexl-find-file} instead of @kbd{C-x C-f} to visit
1788 the file. This command converts the file's contents to hexadecimal and
1789 lets you edit the translation. When you save the file, it is converted
1790 automatically back to binary.
1792 You can also use @kbd{M-x hexl-mode} to translate an existing buffer
1793 into hex. This is useful if you visit a file normally and then discover
1794 it is a binary file.
1796 Ordinary text characters overwrite in Hexl mode. This is to reduce
1797 the risk of accidentally spoiling the alignment of data in the file.
1798 There are special commands for insertion. Here is a list of the
1799 commands of Hexl mode:
1801 @c I don't think individual index entries for these commands are useful--RMS.
1804 Insert a byte with a code typed in decimal.
1807 Insert a byte with a code typed in octal.
1810 Insert a byte with a code typed in hex.
1813 Move to the beginning of a 1k-byte ``page.''
1816 Move to the end of a 1k-byte ``page.''
1819 Move to an address specified in hex.
1822 Move to an address specified in decimal.
1825 Leave Hexl mode, going back to the major mode this buffer had before you
1826 invoked @code{hexl-mode}.
1830 Other Hexl commands let you insert strings (sequences) of binary
1831 bytes, move by short's or int's, etc.; type @kbd{C-h a hexl-
1832 @key{RET}} for details.
1835 @node Saving Emacs Sessions, Recursive Edit, Editing Binary Files, Top
1836 @section Saving Emacs Sessions
1837 @cindex saving sessions
1838 @cindex restore session
1839 @cindex remember editing session
1840 @cindex reload files
1843 You can use the Desktop library to save the state of Emacs from one
1844 session to another. Saving the state means that Emacs starts up with
1845 the same set of buffers, major modes, buffer positions, and so on that
1846 the previous Emacs session had.
1848 @vindex desktop-enable
1849 To use Desktop, you should use the Customization buffer (@pxref{Easy
1850 Customization}) to set @code{desktop-enable} to a non-@code{nil} value,
1851 or add these lines at the end of your @file{.emacs} file:
1854 (desktop-load-default)
1859 @findex desktop-save
1860 The first time you save the state of the Emacs session, you must do it
1861 manually, with the command @kbd{M-x desktop-save}. Once you have done
1862 that, exiting Emacs will save the state again---not only the present
1863 Emacs session, but also subsequent sessions. You can also save the
1864 state at any time, without exiting Emacs, by typing @kbd{M-x
1865 desktop-save} again.
1867 In order for Emacs to recover the state from a previous session, you
1868 must start it with the same current directory as you used when you
1869 started the previous session. This is because @code{desktop-read} looks
1870 in the current directory for the file to read. This means that you can
1871 have separate saved sessions in different directories; the directory in
1872 which you start Emacs will control which saved session to use.
1874 @vindex desktop-files-not-to-save
1875 The variable @code{desktop-files-not-to-save} controls which files are
1876 excluded from state saving. Its value is a regular expression that
1877 matches the files to exclude. By default, remote (ftp-accessed) files
1878 are excluded; this is because visiting them again in the subsequent
1879 session would be slow. If you want to include these files in state
1880 saving, set @code{desktop-files-not-to-save} to @code{"^$"}.
1881 @xref{Remote Files}.
1885 @findex toggle-save-place
1886 The Saveplace library provides a simpler feature that records your
1887 position in each file when you kill its buffer (or kill Emacs), and
1888 jumps to the same position when you visit the file again (even in
1889 another Emacs session). Use @kbd{M-x toggle-save-place} to turn on
1890 place-saving in a given file. Customize the option @code{save-place}
1891 to turn it on for all files in each session.
1893 @node Recursive Edit, Emulation, Saving Emacs Sessions, Top
1894 @section Recursive Editing Levels
1895 @cindex recursive editing level
1896 @cindex editing level, recursive
1898 A @dfn{recursive edit} is a situation in which you are using Emacs
1899 commands to perform arbitrary editing while in the middle of another
1900 Emacs command. For example, when you type @kbd{C-r} inside of a
1901 @code{query-replace}, you enter a recursive edit in which you can change
1902 the current buffer. On exiting from the recursive edit, you go back to
1903 the @code{query-replace}.
1906 @findex exit-recursive-edit
1907 @cindex exiting recursive edit
1908 @dfn{Exiting} the recursive edit means returning to the unfinished
1909 command, which continues execution. The command to exit is @kbd{C-M-c}
1910 (@code{exit-recursive-edit}).
1912 You can also @dfn{abort} the recursive edit. This is like exiting,
1913 but also quits the unfinished command immediately. Use the command
1914 @kbd{C-]} (@code{abort-recursive-edit}) to do this. @xref{Quitting}.
1916 The mode line shows you when you are in a recursive edit by displaying
1917 square brackets around the parentheses that always surround the major and
1918 minor mode names. Every window's mode line shows this, in the same way,
1919 since being in a recursive edit is true of Emacs as a whole rather than
1920 any particular window or buffer.
1922 It is possible to be in recursive edits within recursive edits. For
1923 example, after typing @kbd{C-r} in a @code{query-replace}, you may type a
1924 command that enters the debugger. This begins a recursive editing level
1925 for the debugger, within the recursive editing level for @kbd{C-r}.
1926 Mode lines display a pair of square brackets for each recursive editing
1927 level currently in progress.
1929 Exiting the inner recursive edit (such as, with the debugger @kbd{c}
1930 command) resumes the command running in the next level up. When that
1931 command finishes, you can then use @kbd{C-M-c} to exit another recursive
1932 editing level, and so on. Exiting applies to the innermost level only.
1933 Aborting also gets out of only one level of recursive edit; it returns
1934 immediately to the command level of the previous recursive edit. If you
1935 wish, you can then abort the next recursive editing level.
1937 Alternatively, the command @kbd{M-x top-level} aborts all levels of
1938 recursive edits, returning immediately to the top-level command reader.
1940 The text being edited inside the recursive edit need not be the same text
1941 that you were editing at top level. It depends on what the recursive edit
1942 is for. If the command that invokes the recursive edit selects a different
1943 buffer first, that is the buffer you will edit recursively. In any case,
1944 you can switch buffers within the recursive edit in the normal manner (as
1945 long as the buffer-switching keys have not been rebound). You could
1946 probably do all the rest of your editing inside the recursive edit,
1947 visiting files and all. But this could have surprising effects (such as
1948 stack overflow) from time to time. So remember to exit or abort the
1949 recursive edit when you no longer need it.
1951 In general, we try to minimize the use of recursive editing levels in
1952 GNU Emacs. This is because they constrain you to ``go back'' in a
1953 particular order---from the innermost level toward the top level. When
1954 possible, we present different activities in separate buffers so that
1955 you can switch between them as you please. Some commands switch to a
1956 new major mode which provides a command to switch back. These
1957 approaches give you more flexibility to go back to unfinished tasks in
1958 the order you choose.
1960 @node Emulation, Hyperlinking, Recursive Edit, Top
1962 @cindex emulating other editors
1963 @cindex other editors
1966 @cindex PC keybindings
1967 @cindex scrolling all windows
1969 @cindex Motif keybindings
1970 @cindex Macintosh keybindings
1973 GNU Emacs can be programmed to emulate (more or less) most other
1974 editors. Standard facilities can emulate these:
1977 @item CRiSP/Brief (PC editor)
1979 @vindex crisp-override-meta-x
1980 @findex scroll-all-mode
1982 @cindex Brief emulation
1983 @cindex emulation of Brief
1985 You can turn on keybindings to emulate the CRiSP/Brief editor with
1986 @kbd{M-x crisp-mode}. Note that this rebinds @kbd{M-x} to exit Emacs
1987 unless you change the user option @code{crisp-override-meta-x}. You can
1988 also use the command @kbd{M-x scroll-all-mode} or set the user option
1989 @code{crisp-load-scroll-all} to emulate CRiSP's scroll-all feature
1990 (scrolling all windows together).
1992 @item EDT (DEC VMS editor)
1993 @findex edt-emulation-on
1994 @findex edt-emulation-off
1995 Turn on EDT emulation with @kbd{M-x edt-emulation-on}. @kbd{M-x
1996 edt-emulation-off} restores normal Emacs command bindings.
1998 Most of the EDT emulation commands are keypad keys, and most standard
1999 Emacs key bindings are still available. The EDT emulation rebindings
2000 are done in the global keymap, so there is no problem switching
2001 buffers or major modes while in EDT emulation.
2003 @item ``PC'' bindings
2004 @findex pc-bindings-mode
2005 @cindex ``PC'' key bindings
2006 The command @kbd{M-x pc-bindings-mode} sets up certain key bindings
2007 for ``PC compatibility''---what people are often used to on PCs---as
2008 follows: @kbd{Delete} and its variants delete forward instead of
2009 backward, @kbd{C-Backspace} kills backward a word (as @kbd{C-Delete}
2010 normally would), @kbd{M-Backspace} does undo, @kbd{Home} and @kbd{End}
2011 move to beginning and end of line, @kbd{C-Home} and @kbd{C-End} move
2012 to beginning and end of buffer and @kbd{C-Escape} does
2013 @code{list-buffers}.
2015 @item PC Selection mode
2016 @findex pc-selection-mode
2017 @cindex PC Selection minor mode
2018 @cindex mode, PC selection
2019 @cindex selection, PC
2020 The command @kbd{M-x pc-selection-mode} enables a global minor mode
2021 that emulates the mark, copy, cut and paste commands of various other
2022 systems---an interface known as CUA. It establishes the keybindings
2023 of PC mode, and also modifies the bindings of the cursor keys and the
2024 @kbd{next}, @kbd{prior}, @kbd{home} and @kbd{end} keys. It does not
2025 provide the full set of CUA keybindings---the fundamental Emacs keys
2026 @kbd{C-c}, @kbd{C-v} and @kbd{C-x} are not changed.
2028 The standard keys for moving around (@kbd{right}, @kbd{left},
2029 @kbd{up}, @kbd{down}, @kbd{home}, @kbd{end}, @kbd{prior}, @kbd{next},
2030 called ``move-keys'') deactivate the mark in PC selection mode.
2031 However, using @kbd{Shift} together with the ``move keys'' activates
2032 the region over which they move. The copy, cut and paste functions
2033 are available on @kbd{C-insert}, @kbd{S-delete} and @kbd{S-insert}
2036 @cindex s-region package
2037 The @code{s-region} package provides similar, but less complete,
2040 @item TPU (DEC VMS editor)
2043 @kbd{M-x tpu-edt-on} turns on emulation of the TPU editor emulating EDT.
2045 @item vi (Berkeley editor)
2047 Viper is the newest emulator for vi. It implements several levels of
2048 emulation; level 1 is closest to vi itself, while level 5 departs
2049 somewhat from strict emulation to take advantage of the capabilities of
2050 Emacs. To invoke Viper, type @kbd{M-x viper-mode}; it will guide you
2051 the rest of the way and ask for the emulation level. @inforef{Top,
2054 @item vi (another emulator)
2056 @kbd{M-x vi-mode} enters a major mode that replaces the previously
2057 established major mode. All of the vi commands that, in real vi, enter
2058 ``input'' mode are programmed instead to return to the previous major
2059 mode. Thus, ordinary Emacs serves as vi's ``input'' mode.
2061 Because vi emulation works through major modes, it does not work
2062 to switch buffers during emulation. Return to normal Emacs first.
2064 If you plan to use vi emulation much, you probably want to bind a key
2065 to the @code{vi-mode} command.
2067 @item vi (alternate emulator)
2069 @kbd{M-x vip-mode} invokes another vi emulator, said to resemble real vi
2070 more thoroughly than @kbd{M-x vi-mode}. ``Input'' mode in this emulator
2071 is changed from ordinary Emacs so you can use @key{ESC} to go back to
2072 emulated vi command mode. To get from emulated vi command mode back to
2073 ordinary Emacs, type @kbd{C-z}.
2075 This emulation does not work through major modes, and it is possible
2076 to switch buffers in various ways within the emulator. It is not
2077 so necessary to assign a key to the command @code{vip-mode} as
2078 it is with @code{vi-mode} because terminating insert mode does
2081 @inforef{Top, VIP, vip}, for full information.
2083 @item WordStar (old wordprocessor)
2084 @findex wordstar-mode
2085 @kbd{M-x wordstar-mode} provides a major mode with WordStar-like
2089 @node Hyperlinking, Dissociated Press, Emulation, Top
2090 @section Hyperlinking and Navigation Features
2092 @cindex hyperlinking
2094 Various modes documented elsewhere have hypertext features so that
2095 you can follow links, usually by clicking @kbd{Mouse-2} on the link or
2096 typing @key{RET} while point is on the link. Info mode, Help mode and
2097 the Dired-like modes are examples. The Tags facility links between
2098 uses and definitions in source files, see @ref{Tags}. Imenu provides
2099 navigation amongst items indexed in the current buffer, see
2100 @ref{Imenu}. Info-lookup provides mode-specific lookup of definitions
2101 in Info indexes, see @ref{Documentation}. Speedbar maintains a frame
2102 in which links to files, and locations in files are displayed, see
2105 Other non-mode-specific facilities described in this section enable
2106 following links from the current buffer in a context-sensitive
2110 * Browse-URL:: Following URLs.
2111 * Goto-address:: Activating URLs.
2112 * FFAP:: Finding files etc. at point.
2113 * Find-func:: Finding function and variable definitions.
2117 @subsection Following URLs
2118 @cindex World Wide Web
2121 @findex browse-url-at-point
2122 @findex browse-url-at-mouse
2127 @item M-x browse-url @key{RET} @var{url} @key{RET}
2128 Load a URL into a Web browser.
2131 The Browse-URL package provides facilities for following URLs specifying
2132 links on the World Wide Web. Usually this works by invoking a web
2133 browser, but you can, for instance, arrange to invoke @code{compose-mail}
2134 from @samp{mailto:} URLs.
2136 The general way to use this feature is to type @kbd{M-x browse-url},
2137 which displays a specified URL. If point is located near a plausible
2138 URL, that URL is used as the default. Other commands are available
2139 which you might like to bind to keys, such as
2140 @code{browse-url-at-point} and @code{browse-url-at-mouse}.
2142 @vindex browse-url-browser-function
2143 You can customize Browse-URL's behavior via various options in the
2144 @code{browse-url} Customize group, particularly
2145 @code{browse-url-browser-function}. You can invoke actions dependent
2146 on the type of URL by defining @code{browse-url-browser-function} as
2147 an association list. The package's commentary available via @kbd{C-h
2148 p} provides more information. Packages with facilities for following
2149 URLs should always go through Browse-URL, so that the customization
2150 options for Browse-URL will affect all browsing in Emacs.
2153 @subsection Activating URLs
2154 @findex goto-address
2155 @cindex Goto-address
2156 @cindex URLs, activating
2159 @item M-x goto-address
2160 Activate URLs and e-mail addresses in the current buffer.
2163 You can make URLs in the current buffer active with @kbd{M-x
2164 goto-address}. This finds all the URLs in the buffer, and establishes
2165 bindings for @kbd{Mouse-2} and @kbd{C-c @key{RET}} on them. After
2166 activation, if you click on a URL with @kbd{Mouse-2}, or move to a URL
2167 and type @kbd{C-c @key{RET}}, that will display the web page that the URL
2168 specifies. For a @samp{mailto} URL, it sends mail instead, using your
2169 selected mail-composition method (@pxref{Mail Methods}).
2171 It can be useful to add @code{goto-address} to mode hooks and the
2172 hooks used to display an incoming message.
2173 @code{rmail-show-message-hook} is the appropriate hook for Rmail, and
2174 @code{mh-show-mode-hook} for MH-E. This is not needed for Gnus,
2175 which has a similar feature of its own.
2179 @subsection Finding Files and URLs at Point
2180 @findex find-file-at-point
2182 @findex ffap-dired-at-point
2185 @cindex finding file at point
2187 FFAP mode replaces certain key bindings for finding files, including
2188 @kbd{C-x C-f}, with commands that provide more sensitive defaults.
2189 These commands behave like the ordinary ones when given a prefix
2190 argument. Otherwise, they get the default file name or URL from the
2191 text around point. If what is found in the buffer has the form of a
2192 URL rather than a file name, the commands use @code{browse-url} to
2195 This feature is useful for following references in mail or news
2196 buffers, @file{README} files, @file{MANIFEST} files, and so on. The
2197 @samp{ffap} package's commentary available via @kbd{C-h p} and the
2198 @code{ffap} Custom group provide details.
2200 @cindex FFAP minor mode
2202 You can turn on FFAP minor mode to make the following key bindings
2203 and to install hooks for using @code{ffap} in Rmail, Gnus and VM
2207 @item C-x C-f @var{filename} @key{RET}
2208 @kindex C-x C-f @r{(FFAP)}
2209 Find @var{filename}, guessing a default from text around point
2210 (@code{find-file-at-point}).
2212 @kindex C-x 4 f @r{(FFAP)}
2213 @code{ffap-other-window}, analogous to @code{find-file-other-window}.
2215 @kindex C-x 5 f @r{(FFAP)}
2216 @code{ffap-other-frame}, analogous to @code{find-file-other-frame}.
2218 Search buffer for next file name or URL, then find that file or URL.
2219 @item C-x d @var{directory} @key{RET}
2220 @kindex C-x d @r{(FFAP)}
2221 Start Dired on @var{directory}, defaulting to the directory name at
2222 point (@code{ffap-dired-at-point}).
2224 @kindex S-Mouse-3 @r{(FFAP)}
2225 @code{ffap-at-mouse} finds the file guessed from text around the position
2228 @kindex C-S-Mouse-3 @r{(FFAP)}
2229 Display a menu of files and URLs mentioned in current buffer, then
2230 find the one you select (@code{ffap-menu}).
2234 @subsection Finding Function and Variable Definitions
2235 @cindex definitions, finding in Lisp sources
2236 @cindex Lisp definitions, finding in sources
2239 @item M-x find-function @key{RET} @var{function} @key{RET}
2240 Find the definition of @var{function} in its source file.
2241 @item M-x find-variable @key{RET} @var{variable} @key{RET}
2242 Find the definition of @var{variable} in its source file.
2243 @item M-x find-function-on-key @key{RET} @var{key}
2244 Find the definition of the function that @var{key} invokes.
2247 These commands provide an easy way to find the definitions of Emacs
2248 Lisp functions and variables. They are similar in purpose to the Tags
2249 facility (@pxref{Tags}), but don't require a tags table; on the other
2250 hand, they only works for function and variable definitions that are
2251 already loaded in the Emacs session.
2253 @findex find-function
2254 @findex find-function-on-key
2255 @findex find-variable
2256 To find the definition of a function, use @kbd{M-x find-function}.
2257 @kbd{M-x find-variable} finds the definition of a specified variable.
2258 @kbd{M-x find-function-on-key} finds the definition of the function
2259 bound to a specified key.
2261 To use these commands, you must have the Lisp source (@samp{.el})
2262 files available along with the compiled (@samp{.elc}) files, in
2263 directories in @code{load-path}. You can use compressed source files
2264 if you enable Auto Compression mode. These commands only handle
2265 definitions written in Lisp, not primitive functions or variables
2266 defined in the C code of Emacs.
2268 @node Dissociated Press, Amusements, Hyperlinking, Top
2269 @section Dissociated Press
2271 @findex dissociated-press
2272 @kbd{M-x dissociated-press} is a command for scrambling a file of text
2273 either word by word or character by character. Starting from a buffer of
2274 straight English, it produces extremely amusing output. The input comes
2275 from the current Emacs buffer. Dissociated Press writes its output in a
2276 buffer named @samp{*Dissociation*}, and redisplays that buffer after every
2277 couple of lines (approximately) so you can read the output as it comes out.
2279 Dissociated Press asks every so often whether to continue generating
2280 output. Answer @kbd{n} to stop it. You can also stop at any time by
2281 typing @kbd{C-g}. The dissociation output remains in the
2282 @samp{*Dissociation*} buffer for you to copy elsewhere if you wish.
2284 @cindex presidentagon
2285 Dissociated Press operates by jumping at random from one point in the
2286 buffer to another. In order to produce plausible output rather than
2287 gibberish, it insists on a certain amount of overlap between the end of
2288 one run of consecutive words or characters and the start of the next.
2289 That is, if it has just printed out `president' and then decides to jump
2290 to a different point in the file, it might spot the `ent' in `pentagon'
2291 and continue from there, producing `presidentagon'.@footnote{This
2292 dissociword actually appeared during the Vietnam War, when it was very
2293 appropriate.} Long sample texts produce the best results.
2295 @cindex againformation
2296 A positive argument to @kbd{M-x dissociated-press} tells it to operate
2297 character by character, and specifies the number of overlap characters. A
2298 negative argument tells it to operate word by word and specifies the number
2299 of overlap words. In this mode, whole words are treated as the elements to
2300 be permuted, rather than characters. No argument is equivalent to an
2301 argument of two. For your againformation, the output goes only into the
2302 buffer @samp{*Dissociation*}. The buffer you start with is not changed.
2304 @cindex Markov chain
2306 @cindex techniquitous
2307 Dissociated Press produces nearly the same results as a Markov chain
2308 based on a frequency table constructed from the sample text. It is,
2309 however, an independent, ignoriginal invention. Dissociated Press
2310 techniquitously copies several consecutive characters from the sample
2311 between random choices, whereas a Markov chain would choose randomly for
2312 each word or character. This makes for more plausible sounding results,
2319 @cindex developediment
2321 It is a mustatement that too much use of Dissociated Press can be a
2322 developediment to your real work. Sometimes to the point of outragedy.
2323 And keep dissociwords out of your documentation, if you want it to be well
2324 userenced and properbose. Have fun. Your buggestions are welcome.
2326 @node Amusements, Customization, Dissociated Press, Top
2327 @section Other Amusements
2332 @cindex tower of Hanoi
2334 If you are a little bit bored, you can try @kbd{M-x hanoi}. If you are
2335 considerably bored, give it a numeric argument. If you are very very
2336 bored, try an argument of 9. Sit back and watch.
2339 If you want a little more personal involvement, try @kbd{M-x gomoku},
2340 which plays the game Go Moku with you.
2346 @kbd{M-x blackbox}, @kbd{M-x mpuz} and @kbd{M-x 5x5} are kinds of puzzles.
2347 @code{blackbox} challenges you to determine the location of objects
2348 inside a box by tomography. @code{mpuz} displays a multiplication
2349 puzzle with letters standing for digits in a code that you must
2350 guess---to guess a value, type a letter and then the digit you think it
2351 stands for. The aim of @code{5x5} is to fill in all the squares.
2355 @cindex cryptanalysis
2356 @kbd{M-x decipher} helps you to cryptanalyze a buffer which is encrypted
2357 in a simple monoalphabetic substitution cipher.
2360 @kbd{M-x dunnet} runs an adventure-style exploration game, which is
2361 a bigger sort of puzzle.
2364 @cindex landmark game
2365 @kbd{M-x lm} runs a relatively non-participatory game in which a robot
2366 attempts to maneuver towards a tree at the center of the window based on
2367 unique olfactory cues from each of the four directions.
2371 @kbd{M-x life} runs Conway's ``Life'' cellular automaton.
2373 @findex morse-region
2374 @findex unmorse-region
2376 @cindex --/---/.-./.../.
2377 @kbd{M-x morse-region} converts text in a region to Morse code and
2378 @kbd{M-x unmorse-region} converts it back. No cause for remorse.
2382 @kbd{M-x pong} plays a Pong-like game, bouncing the ball off opposing
2387 @kbd{M-x solitaire} plays a game of solitaire in which you jump pegs
2390 @findex studlify-region
2392 @kbd{M-x studlify-region} studlify-cases the region, producing
2396 M-x stUdlIfY-RegioN stUdlIfY-CaSeS thE region.
2403 @kbd{M-x tetris} runs an implementation of the well-known Tetris game.
2404 Likewise, @kbd{M-x snake} provides an implementation of Snake.
2406 When you are frustrated, try the famous Eliza program. Just do
2407 @kbd{M-x doctor}. End each input by typing @key{RET} twice.
2410 When you are feeling strange, type @kbd{M-x yow}.
2413 The command @kbd{M-x zone} plays games with the display when Emacs is