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
395 Both @kbd{M-!} and @kbd{M-|} use @code{shell-file-name} to specify the
396 shell to use. This variable is initialized based on your @env{SHELL}
397 environment variable when Emacs is started. If the file name does not
398 specify a directory, the directories in the list @code{exec-path} are
399 searched; this list is initialized based on the environment variable
400 @env{PATH} when Emacs is started. Your @file{.emacs} file can override
401 either or both of these default initializations.@refill
403 Both @kbd{M-!} and @kbd{M-|} wait for the shell command to complete.
404 To stop waiting, type @kbd{C-g} to quit; that terminates the shell
405 command with the signal @code{SIGINT}---the same signal that @kbd{C-c}
406 normally generates in the shell. Emacs waits until the command actually
407 terminates. If the shell command doesn't stop (because it ignores the
408 @code{SIGINT} signal), type @kbd{C-g} again; this sends the command a
409 @code{SIGKILL} signal which is impossible to ignore.
411 To specify a coding system for @kbd{M-!} or @kbd{M-|}, use the command
412 @kbd{C-x @key{RET} c} immediately beforehand. @xref{Specify Coding}.
414 @vindex shell-command-default-error-buffer
415 Error output from the command is normally intermixed with the regular
416 output. If you set the variable
417 @code{shell-command-default-error-buffer} to a string, which is a buffer
418 name, error output is inserted before point in the buffer of that name.
420 @node Interactive Shell
421 @subsection Interactive Inferior Shell
424 To run a subshell interactively, putting its typescript in an Emacs
425 buffer, use @kbd{M-x shell}. This creates (or reuses) a buffer named
426 @samp{*shell*} and runs a subshell with input coming from and output going
427 to that buffer. That is to say, any ``terminal output'' from the subshell
428 goes into the buffer, advancing point, and any ``terminal input'' for
429 the subshell comes from text in the buffer. To give input to the subshell,
430 go to the end of the buffer and type the input, terminated by @key{RET}.
432 Emacs does not wait for the subshell to do anything. You can switch
433 windows or buffers and edit them while the shell is waiting, or while it is
434 running a command. Output from the subshell waits until Emacs has time to
435 process it; this happens whenever Emacs is waiting for keyboard input or
438 @cindex @code{comint-highlight-input} face
439 @cindex @code{comint-highlight-prompt} face
440 Input lines, once you submit them, are displayed using the face
441 @code{comint-highlight-input}, and prompts are displayed using the
442 face @code{comint-highlight-prompt}. This makes it easier to see
443 previous input lines in the buffer. @xref{Faces}.
445 To make multiple subshells, you can invoke @kbd{M-x shell} with a
446 prefix argument (e.g. @kbd{C-u M-x shell}), which will read a buffer
447 name and create (or reuse) a subshell in that buffer. You can also
448 rename the @samp{*shell*} buffer using @kbd{M-x rename-uniquely}, then
449 create a new @samp{*shell*} buffer using plain @kbd{M-x shell}. All the
450 subshells in different buffers run independently and in parallel.
452 @vindex explicit-shell-file-name
453 @cindex environment variables for subshells
454 @cindex @env{ESHELL} environment variable
455 @cindex @env{SHELL} environment variable
456 The file name used to load the subshell is the value of the variable
457 @code{explicit-shell-file-name}, if that is non-@code{nil}. Otherwise,
458 the environment variable @env{ESHELL} is used, or the environment
459 variable @env{SHELL} if there is no @env{ESHELL}. If the file name
460 specified is relative, the directories in the list @code{exec-path} are
461 searched; this list is initialized based on the environment variable
462 @env{PATH} when Emacs is started. Your @file{.emacs} file can override
463 either or both of these default initializations.
465 Emacs sends the new shell the contents of the file
466 @file{~/.emacs_@var{shellname}} as input, if it exists, where
467 @var{shellname} is the name of the file that the shell was loaded
468 from. For example, if you use bash, the file sent to it is
469 @file{~/.emacs_bash}.
471 To specify a coding system for the shell, you can use the command
472 @kbd{C-x @key{RET} c} immediately before @kbd{M-x shell}. You can also
473 specify a coding system after starting the shell by using @kbd{C-x
474 @key{RET} p} in the shell buffer. @xref{Specify Coding}.
476 @cindex @env{EMACS} environment variable
477 Unless the environment variable @env{EMACS} is already defined,
478 Emacs defines it in the subshell, with value @code{t}. A shell script
479 can check this variable to determine whether it has been run from an
483 @subsection Shell Mode
487 Shell buffers use Shell mode, which defines several special keys
488 attached to the @kbd{C-c} prefix. They are chosen to resemble the usual
489 editing and job control characters present in shells that are not under
490 Emacs, except that you must type @kbd{C-c} first. Here is a complete list
491 of the special key bindings of Shell mode:
495 @kindex RET @r{(Shell mode)}
496 @findex comint-send-input
497 At end of buffer send line as input; otherwise, copy current line to
498 end of buffer and send it (@code{comint-send-input}). When a line is
499 copied, any prompt at the beginning of the line (text output by
500 programs preceding your input) is omitted. (See also the variable
501 @code{comint-use-prompt-regexp-instead-of-fields}.)
504 @kindex TAB @r{(Shell mode)}
505 @findex comint-dynamic-complete
506 Complete the command name or file name before point in the shell buffer
507 (@code{comint-dynamic-complete}). @key{TAB} also completes history
508 references (@pxref{History References}) and environment variable names.
510 @vindex shell-completion-fignore
511 @vindex comint-completion-fignore
512 The variable @code{shell-completion-fignore} specifies a list of file
513 name extensions to ignore in Shell mode completion. The default
514 setting is @code{nil}, but some users prefer @code{("~" "#" "%")} to
515 ignore file names ending in @samp{~}, @samp{#} or @samp{%}. Other
516 related Comint modes use the variable @code{comint-completion-fignore}
520 @kindex M-? @r{(Shell mode)}
521 @findex comint-dynamic-list-filename@dots{}
522 Display temporarily a list of the possible completions of the file name
523 before point in the shell buffer
524 (@code{comint-dynamic-list-filename-completions}).
527 @kindex C-d @r{(Shell mode)}
528 @findex comint-delchar-or-maybe-eof
529 Either delete a character or send @sc{eof}
530 (@code{comint-delchar-or-maybe-eof}). Typed at the end of the shell
531 buffer, @kbd{C-d} sends @sc{eof} to the subshell. Typed at any other
532 position in the buffer, @kbd{C-d} deletes a character as usual.
535 @kindex C-c C-a @r{(Shell mode)}
536 @findex comint-bol-or-process-mark
537 Move to the beginning of the line, but after the prompt if any
538 (@code{comint-bol-or-process-mark}). If you repeat this command twice
539 in a row, the second time it moves back to the process mark, which is
540 the beginning of the input that you have not yet sent to the subshell.
541 (Normally that is the same place---the end of the prompt on this
542 line---but after @kbd{C-c @key{SPC}} the process mark may be in a
546 Accumulate multiple lines of input, then send them together. This
547 command inserts a newline before point, but does not send the preceding
548 text as input to the subshell---at least, not yet. Both lines, the one
549 before this newline and the one after, will be sent together (along with
550 the newline that separates them), when you type @key{RET}.
553 @kindex C-c C-u @r{(Shell mode)}
554 @findex comint-kill-input
555 Kill all text pending at end of buffer to be sent as input
556 (@code{comint-kill-input}).
559 @kindex C-c C-w @r{(Shell mode)}
560 Kill a word before point (@code{backward-kill-word}).
563 @kindex C-c C-c @r{(Shell mode)}
564 @findex comint-interrupt-subjob
565 Interrupt the shell or its current subjob if any
566 (@code{comint-interrupt-subjob}). This command also kills
567 any shell input pending in the shell buffer and not yet sent.
570 @kindex C-c C-z @r{(Shell mode)}
571 @findex comint-stop-subjob
572 Stop the shell or its current subjob if any (@code{comint-stop-subjob}).
573 This command also kills any shell input pending in the shell buffer and
577 @findex comint-quit-subjob
578 @kindex C-c C-\ @r{(Shell mode)}
579 Send quit signal to the shell or its current subjob if any
580 (@code{comint-quit-subjob}). This command also kills any shell input
581 pending in the shell buffer and not yet sent.
584 @kindex C-c C-o @r{(Shell mode)}
585 @findex comint-delete-output
586 Delete the last batch of output from a shell command
587 (@code{comint-delete-output}). This is useful if a shell command spews
588 out lots of output that just gets in the way. This command used to be
589 called @code{comint-kill-output}.
592 @kindex C-c C-s @r{(Shell mode)}
593 @findex comint-write-output
594 Write the last batch of output from a shell command to a file
595 (@code{comint-write-output}). With a prefix argument, the file is
596 appended to instead. Any prompt at the end of the output is not
601 @kindex C-c C-r @r{(Shell mode)}
602 @kindex C-M-l @r{(Shell mode)}
603 @findex comint-show-output
604 Scroll to display the beginning of the last batch of output at the top
605 of the window; also move the cursor there (@code{comint-show-output}).
608 @kindex C-c C-e @r{(Shell mode)}
609 @findex comint-show-maximum-output
610 Scroll to put the end of the buffer at the bottom of the window
611 (@code{comint-show-maximum-output}).
614 @kindex C-c C-f @r{(Shell mode)}
615 @findex shell-forward-command
616 @vindex shell-command-regexp
617 Move forward across one shell command, but not beyond the current line
618 (@code{shell-forward-command}). The variable @code{shell-command-regexp}
619 specifies how to recognize the end of a command.
622 @kindex C-c C-b @r{(Shell mode)}
623 @findex shell-backward-command
624 Move backward across one shell command, but not beyond the current line
625 (@code{shell-backward-command}).
628 @kindex C-c C-l @r{(Shell mode)}
629 @findex comint-dynamic-list-input-ring
630 Display the buffer's history of shell commands in another window
631 (@code{comint-dynamic-list-input-ring}).
634 Ask the shell what its current directory is, so that Emacs can agree
637 @item M-x send-invisible @key{RET} @var{text} @key{RET}
638 @findex send-invisible
639 Send @var{text} as input to the shell, after reading it without
640 echoing. This is useful when a shell command runs a program that asks
643 Alternatively, you can arrange for Emacs to notice password prompts
644 and turn off echoing for them, as follows:
647 (add-hook 'comint-output-filter-functions
648 'comint-watch-for-password-prompt)
651 @item M-x comint-continue-subjob
652 @findex comint-continue-subjob
653 Continue the shell process. This is useful if you accidentally suspend
654 the shell process.@footnote{You should not suspend the shell process.
655 Suspending a subjob of the shell is a completely different matter---that
656 is normal practice, but you must use the shell to continue the subjob;
657 this command won't do it.}
659 @item M-x comint-strip-ctrl-m
660 @findex comint-strip-ctrl-m
661 Discard all control-M characters from the current group of shell output.
662 The most convenient way to use this command is to make it run
663 automatically when you get output from the subshell. To do that,
664 evaluate this Lisp expression:
667 (add-hook 'comint-output-filter-functions
668 'comint-strip-ctrl-m)
671 @item M-x comint-truncate-buffer
672 @findex comint-truncate-buffer
673 This command truncates the shell buffer to a certain maximum number of
674 lines, specified by the variable @code{comint-buffer-maximum-size}.
675 Here's how to do this automatically each time you get output from the
679 (add-hook 'comint-output-filter-functions
680 'comint-truncate-buffer)
684 Shell mode also customizes the paragraph commands so that only shell
685 prompts start new paragraphs. Thus, a paragraph consists of an input
686 command plus the output that follows it in the buffer.
690 Shell mode is a derivative of Comint mode, a general-purpose mode for
691 communicating with interactive subprocesses. Most of the features of
692 Shell mode actually come from Comint mode, as you can see from the
693 command names listed above. The special features of Shell mode include
694 the directory tracking feature, and a few user commands.
696 Other Emacs features that use variants of Comint mode include GUD
697 (@pxref{Debuggers}) and @kbd{M-x run-lisp} (@pxref{External Lisp}).
700 You can use @kbd{M-x comint-run} to execute any program of your choice
701 in a subprocess using unmodified Comint mode---without the
702 specializations of Shell mode.
705 @subsection Shell Command History
707 Shell buffers support three ways of repeating earlier commands. You
708 can use the same keys used in the minibuffer; these work much as they do
709 in the minibuffer, inserting text from prior commands while point
710 remains always at the end of the buffer. You can move through the
711 buffer to previous inputs in their original place, then resubmit them or
712 copy them to the end. Or you can use a @samp{!}-style history
716 * Ring: Shell Ring. Fetching commands from the history list.
717 * Copy: Shell History Copying. Moving to a command and then copying it.
718 * History References:: Expanding @samp{!}-style history references.
722 @subsubsection Shell History Ring
725 @findex comint-previous-input
726 @kindex M-p @r{(Shell mode)}
728 Fetch the next earlier old shell command.
730 @kindex M-n @r{(Shell mode)}
731 @findex comint-next-input
733 Fetch the next later old shell command.
735 @kindex M-r @r{(Shell mode)}
736 @kindex M-s @r{(Shell mode)}
737 @findex comint-previous-matching-input
738 @findex comint-next-matching-input
739 @item M-r @var{regexp} @key{RET}
740 @itemx M-s @var{regexp} @key{RET}
741 Search backwards or forwards for old shell commands that match @var{regexp}.
743 @item C-c C-x @r{(Shell mode)}
744 @findex comint-get-next-from-history
745 Fetch the next subsequent command from the history.
747 @item C-c . @r{(Shell mode)}
748 @findex comint-input-previous-argument
749 Fetch one argument from an old shell command.
752 Shell buffers provide a history of previously entered shell commands. To
753 reuse shell commands from the history, use the editing commands @kbd{M-p},
754 @kbd{M-n}, @kbd{M-r} and @kbd{M-s}. These work just like the minibuffer
755 history commands except that they operate on the text at the end of the
756 shell buffer, where you would normally insert text to send to the shell.
758 @kbd{M-p} fetches an earlier shell command to the end of the shell buffer.
759 Successive use of @kbd{M-p} fetches successively earlier shell commands,
760 each replacing any text that was already present as potential shell input.
761 @kbd{M-n} does likewise except that it finds successively more recent shell
762 commands from the buffer.
764 The history search commands @kbd{M-r} and @kbd{M-s} read a regular
765 expression and search through the history for a matching command. Aside
766 from the choice of which command to fetch, they work just like @kbd{M-p}
767 and @kbd{M-n}. If you enter an empty regexp, these commands reuse the
768 same regexp used last time.
770 When you find the previous input you want, you can resubmit it by
771 typing @key{RET}, or you can edit it first and then resubmit it if you
774 Often it is useful to reexecute several successive shell commands that
775 were previously executed in sequence. To do this, first find and
776 reexecute the first command of the sequence. Then type @kbd{C-c C-x};
777 that will fetch the following command---the one that follows the command
778 you just repeated. Then type @key{RET} to reexecute this command. You
779 can reexecute several successive commands by typing @kbd{C-c C-x
780 @key{RET}} over and over.
782 The command @kbd{C-c .}@: (@code{comint-input-previous-argument})
783 copies an individual argument from a previous command, like @kbd{ESC
784 .} in Bash. The simplest use copies the last argument from the
785 previous shell command. With a prefix argument @var{n}, it copies the
786 @var{n}th argument instead. Repeating @kbd{C-c .} copies from an
787 earlier shell command instead, always using the same value of @var{n}
788 (don't give a prefix argument when you repeat the @kbd{C-c .}
791 These commands get the text of previous shell commands from a special
792 history list, not from the shell buffer itself. Thus, editing the shell
793 buffer, or even killing large parts of it, does not affect the history
794 that these commands access.
796 @vindex shell-input-ring-file-name
797 Some shells store their command histories in files so that you can
798 refer to previous commands from previous shell sessions. Emacs reads
799 the command history file for your chosen shell, to initialize its own
800 command history. The file name is @file{~/.bash_history} for bash,
801 @file{~/.sh_history} for ksh, and @file{~/.history} for other shells.
803 @node Shell History Copying
804 @subsubsection Shell History Copying
807 @kindex C-c C-p @r{(Shell mode)}
808 @findex comint-previous-prompt
810 Move point to the previous prompt (@code{comint-previous-prompt}).
812 @kindex C-c C-n @r{(Shell mode)}
813 @findex comint-next-prompt
815 Move point to the following prompt (@code{comint-next-prompt}).
817 @kindex C-c RET @r{(Shell mode)}
818 @findex comint-copy-old-input
820 Copy the input command which point is in, inserting the copy at the end
821 of the buffer (@code{comint-copy-old-input}). This is useful if you
822 move point back to a previous command. After you copy the command, you
823 can submit the copy as input with @key{RET}. If you wish, you can
824 edit the copy before resubmitting it.
827 Moving to a previous input and then copying it with @kbd{C-c
828 @key{RET}} produces the same results---the same buffer contents---that
829 you would get by using @kbd{M-p} enough times to fetch that previous
830 input from the history list. However, @kbd{C-c @key{RET}} copies the
831 text from the buffer, which can be different from what is in the history
832 list if you edit the input text in the buffer after it has been sent.
834 @node History References
835 @subsubsection Shell History References
836 @cindex history reference
838 Various shells including csh and bash support @dfn{history
839 references} that begin with @samp{!} and @samp{^}. Shell mode
840 recognizes these constructs, and can perform the history substitution
843 If you insert a history reference and type @key{TAB}, this searches
844 the input history for a matching command, performs substitution if
845 necessary, and places the result in the buffer in place of the history
846 reference. For example, you can fetch the most recent command
847 beginning with @samp{mv} with @kbd{! m v @key{TAB}}. You can edit the
848 command if you wish, and then resubmit the command to the shell by
851 @vindex comint-input-autoexpand
852 @findex comint-magic-space
853 Shell mode can optionally expand history references in the buffer
854 when you send them to the shell. To request this, set the variable
855 @code{comint-input-autoexpand} to @code{input}. You can make
856 @key{SPC} perform history expansion by binding @key{SPC} to the
857 command @code{comint-magic-space}.
859 @vindex shell-prompt-pattern
860 @vindex comint-prompt-regexp
861 @vindex comint-use-prompt-regexp-instead-of-fields
862 @cindex prompt, shell
863 Shell mode recognizes history references when they follow a prompt.
864 Normally, any text output by a program at the beginning of an input
865 line is considered a prompt. However, if the variable
866 @code{comint-use-prompt-regexp-instead-of-fields} is non-@code{nil},
867 then Comint mode uses a regular expression to recognize prompts. In
868 general, the variable @code{comint-prompt-regexp} specifies the
869 regular expression; Shell mode uses the variable
870 @code{shell-prompt-pattern} to set up @code{comint-prompt-regexp} in
873 @node Directory Tracking
874 @subsection Directory Tracking
875 @cindex directory tracking
877 @vindex shell-pushd-regexp
878 @vindex shell-popd-regexp
879 @vindex shell-cd-regexp
880 Shell mode keeps track of @samp{cd}, @samp{pushd} and @samp{popd}
881 commands given to the inferior shell, so it can keep the
882 @samp{*shell*} buffer's default directory the same as the shell's
883 working directory. It recognizes these commands syntactically, by
884 examining lines of input that are sent.
886 If you use aliases for these commands, you can tell Emacs to
887 recognize them also. For example, if the value of the variable
888 @code{shell-pushd-regexp} matches the beginning of a shell command
889 line, that line is regarded as a @code{pushd} command. Change this
890 variable when you add aliases for @samp{pushd}. Likewise,
891 @code{shell-popd-regexp} and @code{shell-cd-regexp} are used to
892 recognize commands with the meaning of @samp{popd} and @samp{cd}.
893 These commands are recognized only at the beginning of a shell command
896 @ignore @c This seems to have been deleted long ago.
897 @vindex shell-set-directory-error-hook
898 If Emacs gets an error while trying to handle what it believes is a
899 @samp{cd}, @samp{pushd} or @samp{popd} command, it runs the hook
900 @code{shell-set-directory-error-hook} (@pxref{Hooks}).
904 If Emacs gets confused about changes in the current directory of the
905 subshell, use the command @kbd{M-x dirs} to ask the shell what its
906 current directory is. This command works for shells that support the
907 most common command syntax; it may not work for unusual shells.
909 @findex dirtrack-mode
910 You can also use @kbd{M-x dirtrack-mode} to enable (or disable) an
911 alternative and more aggressive method of tracking changes in the
915 @subsection Shell Mode Options
917 @vindex comint-scroll-to-bottom-on-input
918 If the variable @code{comint-scroll-to-bottom-on-input} is
919 non-@code{nil}, insertion and yank commands scroll the selected window
920 to the bottom before inserting.
922 @vindex comint-scroll-show-maximum-output
923 If @code{comint-scroll-show-maximum-output} is non-@code{nil}, then
924 scrolling due to the arrival of output tries to place the last line of
925 text at the bottom line of the window, so as to show as much useful
926 text as possible. (This mimics the scrolling behavior of many
927 terminals.) The default is @code{nil}.
929 @vindex comint-scroll-to-bottom-on-output
930 By setting @code{comint-scroll-to-bottom-on-output}, you can opt for
931 having point jump to the end of the buffer whenever output arrives---no
932 matter where in the buffer point was before. If the value is
933 @code{this}, point jumps in the selected window. If the value is
934 @code{all}, point jumps in each window that shows the Comint buffer. If
935 the value is @code{other}, point jumps in all nonselected windows that
936 show the current buffer. The default value is @code{nil}, which means
937 point does not jump to the end.
939 @vindex comint-input-ignoredups
940 The variable @code{comint-input-ignoredups} controls whether successive
941 identical inputs are stored in the input history. A non-@code{nil}
942 value means to omit an input that is the same as the previous input.
943 The default is @code{nil}, which means to store each input even if it is
944 equal to the previous input.
946 @vindex comint-completion-addsuffix
947 @vindex comint-completion-recexact
948 @vindex comint-completion-autolist
949 Three variables customize file name completion. The variable
950 @code{comint-completion-addsuffix} controls whether completion inserts a
951 space or a slash to indicate a fully completed file or directory name
952 (non-@code{nil} means do insert a space or slash).
953 @code{comint-completion-recexact}, if non-@code{nil}, directs @key{TAB}
954 to choose the shortest possible completion if the usual Emacs completion
955 algorithm cannot add even a single character.
956 @code{comint-completion-autolist}, if non-@code{nil}, says to list all
957 the possible completions whenever completion is not exact.
959 @vindex shell-completion-execonly
960 Command completion normally considers only executable files.
961 If you set @code{shell-completion-execonly} to @code{nil},
962 it considers nonexecutable files as well.
964 @findex shell-pushd-tohome
965 @findex shell-pushd-dextract
966 @findex shell-pushd-dunique
967 You can configure the behavior of @samp{pushd}. Variables control
968 whether @samp{pushd} behaves like @samp{cd} if no argument is given
969 (@code{shell-pushd-tohome}), pop rather than rotate with a numeric
970 argument (@code{shell-pushd-dextract}), and only add directories to the
971 directory stack if they are not already on it
972 (@code{shell-pushd-dunique}). The values you choose should match the
973 underlying shell, of course.
975 If you want Shell mode to handle color output from shell commands,
976 you can enable ANSI Color mode. Here is how to do this:
979 (add-hook 'shell-mode-hook 'ansi-color-for-comint-mode-on)
982 @node Terminal emulator
983 @subsection Emacs Terminal Emulator
986 To run a subshell in a terminal emulator, putting its typescript in
987 an Emacs buffer, use @kbd{M-x term}. This creates (or reuses) a
988 buffer named @samp{*terminal*}, and runs a subshell with input coming
989 from your keyboard, and output going to that buffer.
991 The terminal emulator uses Term mode, which has two input modes. In
992 line mode, Term basically acts like Shell mode; see @ref{Shell Mode}.
994 In char mode, each character is sent directly to the inferior
995 subshell, as ``terminal input.'' Any ``echoing'' of your input is the
996 responsibility of the subshell. The sole exception is the terminal
997 escape character, which by default is @kbd{C-c} (@pxref{Term Mode}).
998 Any ``terminal output'' from the subshell goes into the buffer,
1001 Some programs (such as Emacs itself) need to control the appearance
1002 on the terminal screen in detail. They do this by sending special
1003 control codes. The exact control codes needed vary from terminal to
1004 terminal, but nowadays most terminals and terminal emulators
1005 (including @code{xterm}) understand the ANSI-standard (VT100-style)
1006 escape sequences. Term mode recognizes these escape sequences, and
1007 handles each one appropriately, changing the buffer so that the
1008 appearance of the window matches what it would be on a real terminal.
1009 You can actually run Emacs inside an Emacs Term window.
1011 The file name used to load the subshell is determined the same way
1012 as for Shell mode. To make multiple terminal emulators, rename the
1013 buffer @samp{*terminal*} to something different using @kbd{M-x
1014 rename-uniquely}, just as with Shell mode.
1016 Unlike Shell mode, Term mode does not track the current directory by
1017 examining your input. But some shells can tell Term what the current
1018 directory is. This is done automatically by @code{bash} version 1.15
1022 @subsection Term Mode
1026 The terminal emulator uses Term mode, which has two input modes. In
1027 line mode, Term basically acts like Shell mode; see @ref{Shell Mode}.
1028 In char mode, each character is sent directly to the inferior
1029 subshell, except for the Term escape character, normally @kbd{C-c}.
1031 To switch between line and char mode, use these commands:
1034 @kindex C-c C-j @r{(Term mode)}
1035 @findex term-char-mode
1037 Switch to line mode. Do nothing if already in line mode.
1039 @kindex C-c C-k @r{(Term mode)}
1040 @findex term-line-mode
1042 Switch to char mode. Do nothing if already in char mode.
1045 The following commands are only available in char mode:
1049 Send a literal @key{C-c} to the sub-shell.
1052 A prefix command to access the global @key{C-x} commands conveniently.
1053 For example, @kbd{C-c C-x o} invokes the global binding of
1054 @kbd{C-x o}, which is normally @samp{other-window}.
1057 @node Paging in Term
1058 @subsection Page-At-A-Time Output
1059 @cindex page-at-a-time
1061 Term mode has a page-at-a-time feature. When enabled it makes
1062 output pause at the end of each screenful.
1065 @kindex C-c C-q @r{(Term mode)}
1066 @findex term-pager-toggle
1068 Toggle the page-at-a-time feature. This command works in both line
1069 and char modes. When page-at-a-time is enabled, the mode-line
1070 displays the word @samp{page}.
1073 With page-at-a-time enabled, whenever Term receives more than a
1074 screenful of output since your last input, it pauses, displaying
1075 @samp{**MORE**} in the mode-line. Type @key{SPC} to display the next
1076 screenful of output. Type @kbd{?} to see your other options. The
1077 interface is similar to the @code{more} program.
1080 @subsection Remote Host Shell
1082 @cindex connecting to remote host
1086 You can login to a remote computer, using whatever commands you
1087 would from a regular terminal (e.g.@: using the @code{telnet} or
1088 @code{rlogin} commands), from a Term window.
1090 A program that asks you for a password will normally suppress
1091 echoing of the password, so the password will not show up in the
1092 buffer. This will happen just as if you were using a real terminal,
1093 if the buffer is in char mode. If it is in line mode, the password is
1094 temporarily visible, but will be erased when you hit return. (This
1095 happens automatically; there is no special password processing.)
1097 When you log in to a different machine, you need to specify the type
1098 of terminal you're using. Terminal types @samp{ansi} or @samp{vt100}
1099 will work on most systems.
1101 @c If you are talking to a Bourne-compatible
1102 @c shell, and your system understands the @env{TERMCAP} variable,
1103 @c you can use the command @kbd{M-x shell-send-termcap}, which
1104 @c sends a string specifying the terminal type and size.
1105 @c (This command is also useful after the window has changed size.)
1107 @c You can of course run @samp{gdb} on that remote computer. One useful
1108 @c trick: If you invoke gdb with the @code{--fullname} option,
1109 @c it will send special commands to Emacs that will cause Emacs to
1110 @c pop up the source files you're debugging. This will work
1111 @c whether or not gdb is running on a different computer than Emacs,
1112 @c as long as Emacs can access the source files specified by gdb.
1115 You cannot log in to a remote computer using the Shell mode.
1116 @c (This will change when Shell is re-written to use Term.)
1117 Instead, Emacs provides two commands for logging in to another computer
1118 and communicating with it through an Emacs buffer using Comint mode:
1121 @item M-x telnet @key{RET} @var{hostname} @key{RET}
1122 Set up a Telnet connection to the computer named @var{hostname}.
1123 @item M-x rlogin @key{RET} @var{hostname} @key{RET}
1124 Set up an Rlogin connection to the computer named @var{hostname}.
1128 Use @kbd{M-x telnet} to set up a Telnet connection to another
1129 computer. (Telnet is the standard Internet protocol for remote login.)
1130 It reads the host name of the other computer as an argument with the
1131 minibuffer. Once the connection is established, talking to the other
1132 computer works like talking to a subshell: you can edit input with the
1133 usual Emacs commands, and send it a line at a time by typing @key{RET}.
1134 The output is inserted in the Telnet buffer interspersed with the input.
1137 @vindex rlogin-explicit-args
1138 Use @kbd{M-x rlogin} to set up an Rlogin connection. Rlogin is
1139 another remote login communication protocol, essentially much like the
1140 Telnet protocol but incompatible with it, and supported only by certain
1141 systems. Rlogin's advantages are that you can arrange not to have to
1142 give your user name and password when communicating between two machines
1143 you frequently use, and that you can make an 8-bit-clean connection.
1144 (To do that in Emacs, set @code{rlogin-explicit-args} to @code{("-8")}
1145 before you run Rlogin.)
1147 @kbd{M-x rlogin} sets up the default file directory of the Emacs
1148 buffer to access the remote host via FTP (@pxref{File Names}), and it
1149 tracks the shell commands that change the current directory, just like
1152 @findex rlogin-directory-tracking-mode
1153 There are two ways of doing directory tracking in an Rlogin
1154 buffer---either with remote directory names
1155 @file{/@var{host}:@var{dir}/} or with local names (that works if the
1156 ``remote'' machine shares file systems with your machine of origin).
1157 You can use the command @code{rlogin-directory-tracking-mode} to switch
1158 modes. No argument means use remote directory names, a positive
1159 argument means use local names, and a negative argument means turn
1160 off directory tracking.
1164 @node Emacs Server, Hardcopy, Shell, Top
1165 @section Using Emacs as a Server
1167 @cindex Emacs as a server
1168 @cindex server, using Emacs as
1169 @cindex @env{EDITOR} environment variable
1171 Various programs such as @code{mail} can invoke your choice of editor
1172 to edit a particular piece of text, such as a message that you are
1173 sending. By convention, most of these programs use the environment
1174 variable @env{EDITOR} to specify which editor to run. If you set
1175 @env{EDITOR} to @samp{emacs}, they invoke Emacs---but in an
1176 inconvenient fashion, by starting a new, separate Emacs process. This
1177 is inconvenient because it takes time and because the new Emacs process
1178 doesn't share the buffers in any existing Emacs process.
1180 You can arrange to use your existing Emacs process as the editor for
1181 programs like @code{mail} by using the Emacs client and Emacs server
1182 programs. Here is how.
1184 @cindex @env{TEXEDIT} environment variable
1185 First, the preparation. Within Emacs, call the function
1186 @code{server-start}. (Your @file{.emacs} file can do this automatically
1187 if you add the expression @code{(server-start)} to it.) Then, outside
1188 Emacs, set the @env{EDITOR} environment variable to @samp{emacsclient}.
1189 (Note that some programs use a different environment variable; for
1190 example, to make @TeX{} use @samp{emacsclient}, you should set the
1191 @env{TEXEDIT} environment variable to @samp{emacsclient +%d %s}.)
1195 Then, whenever any program invokes your specified @env{EDITOR}
1196 program, the effect is to send a message to your principal Emacs telling
1197 it to visit a file. (That's what the program @code{emacsclient} does.)
1198 Emacs displays the buffer immediately and you can immediately begin
1201 When you've finished editing that buffer, type @kbd{C-x #}
1202 (@code{server-edit}). This saves the file and sends a message back to
1203 the @code{emacsclient} program telling it to exit. The programs that
1204 use @env{EDITOR} wait for the ``editor'' (actually, @code{emacsclient})
1205 to exit. @kbd{C-x #} also checks for other pending external requests
1206 to edit various files, and selects the next such file.
1208 You can switch to a server buffer manually if you wish; you don't
1209 have to arrive at it with @kbd{C-x #}. But @kbd{C-x #} is the way to
1210 say that you are finished with one.
1212 @vindex server-kill-new-buffers
1213 @vindex server-temp-file-regexp
1214 Finishing with a server buffer also kills the buffer, unless it
1215 already existed in the Emacs session before the server asked to create
1216 it. However, if you set @code{server-kill-new-buffers} to @code{nil},
1217 then a different criterion is used: finishing with a server buffer
1218 kills it if the file name matches the regular expression
1219 @code{server-temp-file-regexp}. This is set up to distinguish certain
1220 ``temporary'' files.
1222 @vindex server-window
1223 If you set the variable @code{server-window} to a window or a frame,
1224 @kbd{C-x #} displays the server buffer in that window or in that frame.
1226 While @code{mail} or another application is waiting for
1227 @code{emacsclient} to finish, @code{emacsclient} does not read terminal
1228 input. So the terminal that @code{mail} was using is effectively
1229 blocked for the duration. In order to edit with your principal Emacs,
1230 you need to be able to use it without using that terminal. There are
1231 three ways to do this:
1235 Using a window system, run @code{mail} and the principal Emacs in two
1236 separate windows. While @code{mail} is waiting for @code{emacsclient},
1237 the window where it was running is blocked, but you can use Emacs by
1241 Using virtual terminals, run @code{mail} in one virtual terminal
1242 and run Emacs in another.
1245 Use Shell mode or Term mode in Emacs to run the other program such as
1246 @code{mail}; then, @code{emacsclient} blocks only the subshell under
1247 Emacs, and you can still use Emacs to edit the file.
1250 If you run @code{emacsclient} with the option @samp{--no-wait}, it
1251 returns immediately without waiting for you to ``finish'' the buffer
1252 in Emacs. Note that server buffers created in this way are not killed
1253 automatically when you finish with them.
1256 * Invoking emacsclient::
1259 @node Invoking emacsclient,, Emacs Server, Emacs Server
1260 @section Invoking @code{emacsclient}
1262 To run the @code{emacsclient} program, specify file names as arguments,
1263 and optionally line numbers as well. Do it like this:
1266 emacsclient @r{@{}@r{[}+@var{line}@r{[}@var{column}@r{]}@r{]} @var{filename}@r{@}}@dots{}
1270 This tells Emacs to visit each of the specified files; if you specify a
1271 line number for a certain file, Emacs moves to that line in the file.
1272 If you specify a column number as well, Emacs puts point on that column
1275 Ordinarily, @code{emacsclient} does not return until you use the
1276 @kbd{C-x #} command on each of these buffers. When that happens,
1277 Emacs sends a message to the @code{emacsclient} program telling it to
1280 But if you use the option @samp{-n} or @samp{--no-wait} when running
1281 @code{emacsclient}, then it returns immediately. (You can take as
1282 long as you like to edit the files in Emacs.)
1284 The option @samp{--alternate-editor=@var{command}} is useful when
1285 running @code{emacsclient} in a script. It specifies a command to run
1286 if @code{emacsclient} fails to contact Emacs. For example, the
1287 following setting for the @var{EDITOR} environment variable will
1288 always give an editor, even if Emacs is not running:
1291 EDITOR="emacsclient --alternate-editor vi +%d %s"
1295 The environment variable @var{ALTERNATE_EDITOR} has the same effect, but
1296 the value of the @samp{--alternate-editor} takes precedence.
1299 Alternatively, the file @file{etc/emacs.bash} defines a bash
1300 function which will communicate with a running Emacs server, or start
1303 @node Hardcopy, PostScript, Emacs Server, Top
1304 @section Hardcopy Output
1307 The Emacs commands for making hardcopy let you print either an entire
1308 buffer or just part of one, either with or without page headers.
1309 See also the hardcopy commands of Dired (@pxref{Misc File Ops})
1310 and the diary (@pxref{Diary Commands}).
1313 @item M-x print-buffer
1314 Print hardcopy of current buffer with page headings containing the file
1315 name and page number.
1316 @item M-x lpr-buffer
1317 Print hardcopy of current buffer without page headings.
1318 @item M-x print-region
1319 Like @code{print-buffer} but print only the current region.
1320 @item M-x lpr-region
1321 Like @code{lpr-buffer} but print only the current region.
1324 @findex print-buffer
1325 @findex print-region
1328 @vindex lpr-switches
1329 The hardcopy commands (aside from the Postscript commands) pass extra
1330 switches to the @code{lpr} program based on the value of the variable
1331 @code{lpr-switches}. Its value should be a list of strings, each string
1332 an option starting with @samp{-}. For example, to specify a line width
1333 of 80 columns for all the printing you do in Emacs, set
1334 @code{lpr-switches} like this:
1337 (setq lpr-switches '("-w80"))
1340 @vindex printer-name
1341 You can specify the printer to use by setting the variable
1342 @code{printer-name}.
1344 @vindex lpr-headers-switches
1345 @vindex lpr-commands
1346 @vindex lpr-add-switches
1347 The variable @code{lpr-command} specifies the name of the printer
1348 program to run; the default value depends on your operating system type.
1349 On most systems, the default is @code{"lpr"}. The variable
1350 @code{lpr-headers-switches} similarly specifies the extra switches to
1351 use to make page headers. The variable @code{lpr-add-switches} controls
1352 whether to supply @samp{-T} and @samp{-J} options (suitable for
1353 @code{lpr}) to the printer program: @code{nil} means don't add them.
1354 @code{lpr-add-switches} should be @code{nil} if your printer program is
1355 not compatible with @code{lpr}.
1357 @node PostScript, PostScript Variables, Hardcopy, Top
1358 @section PostScript Hardcopy
1360 These commands convert buffer contents to PostScript,
1361 either printing it or leaving it in another Emacs buffer.
1364 @item M-x ps-print-buffer
1365 Print hardcopy of the current buffer in PostScript form.
1366 @item M-x ps-print-region
1367 Print hardcopy of the current region in PostScript form.
1368 @item M-x ps-print-buffer-with-faces
1369 Print hardcopy of the current buffer in PostScript form, showing the
1370 faces used in the text by means of PostScript features.
1371 @item M-x ps-print-region-with-faces
1372 Print hardcopy of the current region in PostScript form, showing the
1373 faces used in the text.
1374 @item M-x ps-spool-buffer
1375 Generate PostScript for the current buffer text.
1376 @item M-x ps-spool-region
1377 Generate PostScript for the current region.
1378 @item M-x ps-spool-buffer-with-faces
1379 Generate PostScript for the current buffer, showing the faces used.
1380 @item M-x ps-spool-region-with-faces
1381 Generate PostScript for the current region, showing the faces used.
1383 Generates/prints PostScript for the current buffer as if handwritten.
1386 @findex ps-print-region
1387 @findex ps-print-buffer
1388 @findex ps-print-region-with-faces
1389 @findex ps-print-buffer-with-faces
1390 The PostScript commands, @code{ps-print-buffer} and
1391 @code{ps-print-region}, print buffer contents in PostScript form. One
1392 command prints the entire buffer; the other, just the region. The
1393 corresponding @samp{-with-faces} commands,
1394 @code{ps-print-buffer-with-faces} and @code{ps-print-region-with-faces},
1395 use PostScript features to show the faces (fonts and colors) in the text
1396 properties of the text being printed.
1398 If you are using a color display, you can print a buffer of program
1399 code with color highlighting by turning on Font-Lock mode in that
1400 buffer, and using @code{ps-print-buffer-with-faces}.
1402 @findex ps-spool-region
1403 @findex ps-spool-buffer
1404 @findex ps-spool-region-with-faces
1405 @findex ps-spool-buffer-with-faces
1406 The commands whose names have @samp{spool} instead of @samp{print}
1407 generate the PostScript output in an Emacs buffer instead of sending
1412 @kbd{M-x handwrite} is more frivolous. It generates a PostScript
1413 rendition of the current buffer as a cursive handwritten document. It
1414 can be customized in group @code{handwrite}. This function only
1415 supports ISO 8859-1 characters.
1418 The following section describes variables for customizing these commands.
1421 @node PostScript Variables, Sorting, PostScript, Top
1422 @section Variables for PostScript Hardcopy
1424 @vindex ps-lpr-command
1425 @vindex ps-lpr-switches
1426 @vindex ps-printer-name
1427 All the PostScript hardcopy commands use the variables
1428 @code{ps-lpr-command} and @code{ps-lpr-switches} to specify how to print
1429 the output. @code{ps-lpr-command} specifies the command name to run,
1430 @code{ps-lpr-switches} specifies command line options to use, and
1431 @code{ps-printer-name} specifies the printer. If you don't set the
1432 first two variables yourself, they take their initial values from
1433 @code{lpr-command} and @code{lpr-switches}. If @code{ps-printer-name}
1434 is @code{nil}, @code{printer-name} is used.
1436 @vindex ps-print-header
1437 The variable @code{ps-print-header} controls whether these commands
1438 add header lines to each page---set it to @code{nil} to turn headers
1441 @cindex color emulation on black-and-white printers
1442 @vindex ps-print-color-p
1443 If your printer doesn't support colors, you should turn off color
1444 processing by setting @code{ps-print-color-p} to @code{nil}. By
1445 default, if the display supports colors, Emacs produces hardcopy output
1446 with color information; on black-and-white printers, colors are emulated
1447 with shades of gray. This might produce illegible output, even if your
1448 screen colors only use shades of gray.
1450 @vindex ps-use-face-background
1451 By default, PostScript printing ignores the background colors of the
1452 faces, unless the variable @code{ps-use-face-background} is
1453 non-@code{nil}. This is to avoid unwanted interference with the zebra
1454 stripes and background image/text.
1456 @vindex ps-paper-type
1457 @vindex ps-page-dimensions-database
1458 The variable @code{ps-paper-type} specifies which size of paper to
1459 format for; legitimate values include @code{a4}, @code{a3},
1460 @code{a4small}, @code{b4}, @code{b5}, @code{executive}, @code{ledger},
1461 @code{legal}, @code{letter}, @code{letter-small}, @code{statement},
1462 @code{tabloid}. The default is @code{letter}. You can define
1463 additional paper sizes by changing the variable
1464 @code{ps-page-dimensions-database}.
1466 @vindex ps-landscape-mode
1467 The variable @code{ps-landscape-mode} specifies the orientation of
1468 printing on the page. The default is @code{nil}, which stands for
1469 ``portrait'' mode. Any non-@code{nil} value specifies ``landscape''
1472 @vindex ps-number-of-columns
1473 The variable @code{ps-number-of-columns} specifies the number of
1474 columns; it takes effect in both landscape and portrait mode. The
1477 @vindex ps-font-family
1478 @vindex ps-font-size
1479 @vindex ps-font-info-database
1480 The variable @code{ps-font-family} specifies which font family to use
1481 for printing ordinary text. Legitimate values include @code{Courier},
1482 @code{Helvetica}, @code{NewCenturySchlbk}, @code{Palatino} and
1483 @code{Times}. The variable @code{ps-font-size} specifies the size of
1484 the font for ordinary text. It defaults to 8.5 points.
1486 @vindex ps-multibyte-buffer
1487 @cindex Intlfonts for PostScript printing
1488 @cindex fonts for PostScript printing
1489 Emacs supports more scripts and characters than a typical PostScript
1490 printer. Thus, some of the characters in your buffer might not be
1491 printable using the fonts built into your printer. You can augment
1492 the fonts supplied with the printer with those from the GNU Intlfonts
1493 package, or you can instruct Emacs to use Intlfonts exclusively. The
1494 variable @code{ps-multibyte-buffer} controls this: the default value,
1495 @code{nil}, is appropriate for printing ASCII and Latin-1
1496 characters; a value of @code{non-latin-printer} is for printers which
1497 have the fonts for ASCII, Latin-1, Japanese, and Korean
1498 characters built into them. A value of @code{bdf-font} arranges for
1499 the BDF fonts from the Intlfonts package to be used for @emph{all}
1500 characters. Finally, a value of @code{bdf-font-except-latin}
1501 instructs the printer to use built-in fonts for ASCII and Latin-1
1502 characters, and Intlfonts BDF fonts for the rest.
1504 @vindex bdf-directory-list
1505 To be able to use the BDF fonts, Emacs needs to know where to find
1506 them. The variable @code{bdf-directory-list} holds the list of
1507 directories where Emacs should look for the fonts; the default value
1508 includes a single directory @file{/usr/local/share/emacs/fonts/bdf}.
1510 Many other customization variables for these commands are defined and
1511 described in the Lisp files @file{ps-print.el} and @file{ps-mule.el}.
1513 @node Sorting, Narrowing, PostScript Variables, Top
1514 @section Sorting Text
1517 Emacs provides several commands for sorting text in the buffer. All
1518 operate on the contents of the region (the text between point and the
1519 mark). They divide the text of the region into many @dfn{sort records},
1520 identify a @dfn{sort key} for each record, and then reorder the records
1521 into the order determined by the sort keys. The records are ordered so
1522 that their keys are in alphabetical order, or, for numeric sorting, in
1523 numeric order. In alphabetic sorting, all upper-case letters `A' through
1524 `Z' come before lower-case `a', in accord with the ASCII character
1527 The various sort commands differ in how they divide the text into sort
1528 records and in which part of each record is used as the sort key. Most of
1529 the commands make each line a separate sort record, but some commands use
1530 paragraphs or pages as sort records. Most of the sort commands use each
1531 entire sort record as its own sort key, but some use only a portion of the
1532 record as the sort key.
1535 @findex sort-paragraphs
1538 @findex sort-numeric-fields
1539 @vindex sort-numeric-base
1541 @item M-x sort-lines
1542 Divide the region into lines, and sort by comparing the entire
1543 text of a line. A numeric argument means sort into descending order.
1545 @item M-x sort-paragraphs
1546 Divide the region into paragraphs, and sort by comparing the entire
1547 text of a paragraph (except for leading blank lines). A numeric
1548 argument means sort into descending order.
1550 @item M-x sort-pages
1551 Divide the region into pages, and sort by comparing the entire
1552 text of a page (except for leading blank lines). A numeric
1553 argument means sort into descending order.
1555 @item M-x sort-fields
1556 Divide the region into lines, and sort by comparing the contents of
1557 one field in each line. Fields are defined as separated by
1558 whitespace, so the first run of consecutive non-whitespace characters
1559 in a line constitutes field 1, the second such run constitutes field
1562 Specify which field to sort by with a numeric argument: 1 to sort by
1563 field 1, etc. A negative argument means count fields from the right
1564 instead of from the left; thus, minus 1 means sort by the last field.
1565 If several lines have identical contents in the field being sorted, they
1566 keep the same relative order that they had in the original buffer.
1568 @item M-x sort-numeric-fields
1569 Like @kbd{M-x sort-fields} except the specified field is converted
1570 to an integer for each line, and the numbers are compared. @samp{10}
1571 comes before @samp{2} when considered as text, but after it when
1572 considered as a number. By default, numbers are interpreted according
1573 to @code{sort-numeric-base}, but numbers beginning with @samp{0x} or
1574 @samp{0} are interpreted as hexadecimal and octal, respectively.
1576 @item M-x sort-columns
1577 Like @kbd{M-x sort-fields} except that the text within each line
1578 used for comparison comes from a fixed range of columns. See below
1581 @item M-x reverse-region
1582 Reverse the order of the lines in the region. This is useful for
1583 sorting into descending order by fields or columns, since those sort
1584 commands do not have a feature for doing that.
1587 For example, if the buffer contains this:
1590 On systems where clash detection (locking of files being edited) is
1591 implemented, Emacs also checks the first time you modify a buffer
1592 whether the file has changed on disk since it was last visited or
1593 saved. If it has, you are asked to confirm that you want to change
1598 applying @kbd{M-x sort-lines} to the entire buffer produces this:
1601 On systems where clash detection (locking of files being edited) is
1602 implemented, Emacs also checks the first time you modify a buffer
1603 saved. If it has, you are asked to confirm that you want to change
1605 whether the file has changed on disk since it was last visited or
1609 where the upper-case @samp{O} sorts before all lower-case letters. If
1610 you use @kbd{C-u 2 M-x sort-fields} instead, you get this:
1613 implemented, Emacs also checks the first time you modify a buffer
1614 saved. If it has, you are asked to confirm that you want to change
1616 On systems where clash detection (locking of files being edited) is
1617 whether the file has changed on disk since it was last visited or
1621 where the sort keys were @samp{Emacs}, @samp{If}, @samp{buffer},
1622 @samp{systems} and @samp{the}.
1624 @findex sort-columns
1625 @kbd{M-x sort-columns} requires more explanation. You specify the
1626 columns by putting point at one of the columns and the mark at the other
1627 column. Because this means you cannot put point or the mark at the
1628 beginning of the first line of the text you want to sort, this command
1629 uses an unusual definition of ``region'': all of the line point is in is
1630 considered part of the region, and so is all of the line the mark is in,
1631 as well as all the lines in between.
1633 For example, to sort a table by information found in columns 10 to 15,
1634 you could put the mark on column 10 in the first line of the table, and
1635 point on column 15 in the last line of the table, and then run
1636 @code{sort-columns}. Equivalently, you could run it with the mark on
1637 column 15 in the first line and point on column 10 in the last line.
1639 This can be thought of as sorting the rectangle specified by point and
1640 the mark, except that the text on each line to the left or right of the
1641 rectangle moves along with the text inside the rectangle.
1644 @vindex sort-fold-case
1645 Many of the sort commands ignore case differences when comparing, if
1646 @code{sort-fold-case} is non-@code{nil}.
1648 @node Narrowing, Two-Column, Sorting, Top
1653 @cindex accessible portion
1655 @dfn{Narrowing} means focusing in on some portion of the buffer,
1656 making the rest temporarily inaccessible. The portion which you can
1657 still get to is called the @dfn{accessible portion}. Canceling the
1658 narrowing, which makes the entire buffer once again accessible, is
1659 called @dfn{widening}. The amount of narrowing in effect in a buffer at
1660 any time is called the buffer's @dfn{restriction}.
1662 Narrowing can make it easier to concentrate on a single subroutine or
1663 paragraph by eliminating clutter. It can also be used to restrict the
1664 range of operation of a replace command or repeating keyboard macro.
1668 Narrow down to between point and mark (@code{narrow-to-region}).
1670 Widen to make the entire buffer accessible again (@code{widen}).
1672 Narrow down to the current page (@code{narrow-to-page}).
1674 Narrow down to the current defun (@code{narrow-to-defun}).
1677 When you have narrowed down to a part of the buffer, that part appears
1678 to be all there is. You can't see the rest, you can't move into it
1679 (motion commands won't go outside the accessible part), you can't change
1680 it in any way. However, it is not gone, and if you save the file all
1681 the inaccessible text will be saved. The word @samp{Narrow} appears in
1682 the mode line whenever narrowing is in effect.
1685 @findex narrow-to-region
1686 The primary narrowing command is @kbd{C-x n n} (@code{narrow-to-region}).
1687 It sets the current buffer's restrictions so that the text in the current
1688 region remains accessible, but all text before the region or after the
1689 region is inaccessible. Point and mark do not change.
1692 @findex narrow-to-page
1694 @findex narrow-to-defun
1695 Alternatively, use @kbd{C-x n p} (@code{narrow-to-page}) to narrow
1696 down to the current page. @xref{Pages}, for the definition of a page.
1697 @kbd{C-x n d} (@code{narrow-to-defun}) narrows down to the defun
1698 containing point (@pxref{Defuns}).
1702 The way to cancel narrowing is to widen with @kbd{C-x n w}
1703 (@code{widen}). This makes all text in the buffer accessible again.
1705 You can get information on what part of the buffer you are narrowed down
1706 to using the @kbd{C-x =} command. @xref{Position Info}.
1708 Because narrowing can easily confuse users who do not understand it,
1709 @code{narrow-to-region} is normally a disabled command. Attempting to use
1710 this command asks for confirmation and gives you the option of enabling it;
1711 if you enable the command, confirmation will no longer be required for
1712 it. @xref{Disabling}.
1714 @node Two-Column, Editing Binary Files, Narrowing, Top
1715 @section Two-Column Editing
1716 @cindex two-column editing
1717 @cindex splitting columns
1718 @cindex columns, splitting
1720 Two-column mode lets you conveniently edit two side-by-side columns of
1721 text. It uses two side-by-side windows, each showing its own
1724 There are three ways to enter two-column mode:
1727 @item @kbd{@key{F2} 2} or @kbd{C-x 6 2}
1730 @findex 2C-two-columns
1731 Enter two-column mode with the current buffer on the left, and on the
1732 right, a buffer whose name is based on the current buffer's name
1733 (@code{2C-two-columns}). If the right-hand buffer doesn't already
1734 exist, it starts out empty; the current buffer's contents are not
1737 This command is appropriate when the current buffer is empty or contains
1738 just one column and you want to add another column.
1740 @item @kbd{@key{F2} s} or @kbd{C-x 6 s}
1744 Split the current buffer, which contains two-column text, into two
1745 buffers, and display them side by side (@code{2C-split}). The current
1746 buffer becomes the left-hand buffer, but the text in the right-hand
1747 column is moved into the right-hand buffer. The current column
1748 specifies the split point. Splitting starts with the current line and
1749 continues to the end of the buffer.
1751 This command is appropriate when you have a buffer that already contains
1752 two-column text, and you wish to separate the columns temporarily.
1754 @item @kbd{@key{F2} b @var{buffer} @key{RET}}
1755 @itemx @kbd{C-x 6 b @var{buffer} @key{RET}}
1758 @findex 2C-associate-buffer
1759 Enter two-column mode using the current buffer as the left-hand buffer,
1760 and using buffer @var{buffer} as the right-hand buffer
1761 (@code{2C-associate-buffer}).
1764 @kbd{@key{F2} s} or @kbd{C-x 6 s} looks for a column separator, which
1765 is a string that appears on each line between the two columns. You can
1766 specify the width of the separator with a numeric argument to
1767 @kbd{@key{F2} s}; that many characters, before point, constitute the
1768 separator string. By default, the width is 1, so the column separator
1769 is the character before point.
1771 When a line has the separator at the proper place, @kbd{@key{F2} s}
1772 puts the text after the separator into the right-hand buffer, and
1773 deletes the separator. Lines that don't have the column separator at
1774 the proper place remain unsplit; they stay in the left-hand buffer, and
1775 the right-hand buffer gets an empty line to correspond. (This is the
1776 way to write a line that ``spans both columns while in two-column
1777 mode'': write it in the left-hand buffer, and put an empty line in the
1783 The command @kbd{C-x 6 @key{RET}} or @kbd{@key{F2} @key{RET}}
1784 (@code{2C-newline}) inserts a newline in each of the two buffers at
1785 corresponding positions. This is the easiest way to add a new line to
1786 the two-column text while editing it in split buffers.
1791 When you have edited both buffers as you wish, merge them with
1792 @kbd{@key{F2} 1} or @kbd{C-x 6 1} (@code{2C-merge}). This copies the
1793 text from the right-hand buffer as a second column in the other buffer.
1794 To go back to two-column editing, use @kbd{@key{F2} s}.
1798 @findex 2C-dissociate
1799 Use @kbd{@key{F2} d} or @kbd{C-x 6 d} to dissociate the two buffers,
1800 leaving each as it stands (@code{2C-dissociate}). If the other buffer,
1801 the one not current when you type @kbd{@key{F2} d}, is empty,
1802 @kbd{@key{F2} d} kills it.
1804 @node Editing Binary Files, Saving Emacs Sessions, Two-Column, Top
1805 @section Editing Binary Files
1809 @cindex editing binary files
1811 There is a special major mode for editing binary files: Hexl mode. To
1812 use it, use @kbd{M-x hexl-find-file} instead of @kbd{C-x C-f} to visit
1813 the file. This command converts the file's contents to hexadecimal and
1814 lets you edit the translation. When you save the file, it is converted
1815 automatically back to binary.
1817 You can also use @kbd{M-x hexl-mode} to translate an existing buffer
1818 into hex. This is useful if you visit a file normally and then discover
1819 it is a binary file.
1821 Ordinary text characters overwrite in Hexl mode. This is to reduce
1822 the risk of accidentally spoiling the alignment of data in the file.
1823 There are special commands for insertion. Here is a list of the
1824 commands of Hexl mode:
1826 @c I don't think individual index entries for these commands are useful--RMS.
1829 Insert a byte with a code typed in decimal.
1832 Insert a byte with a code typed in octal.
1835 Insert a byte with a code typed in hex.
1838 Move to the beginning of a 1k-byte ``page.''
1841 Move to the end of a 1k-byte ``page.''
1844 Move to an address specified in hex.
1847 Move to an address specified in decimal.
1850 Leave Hexl mode, going back to the major mode this buffer had before you
1851 invoked @code{hexl-mode}.
1855 Other Hexl commands let you insert strings (sequences) of binary
1856 bytes, move by @code{short}s or @code{int}s, etc.; type @kbd{C-h a
1857 hexl-@key{RET}} for details.
1860 @node Saving Emacs Sessions, Recursive Edit, Editing Binary Files, Top
1861 @section Saving Emacs Sessions
1862 @cindex saving sessions
1863 @cindex restore session
1864 @cindex remember editing session
1865 @cindex reload files
1868 You can use the Desktop library to save the state of Emacs from one
1869 session to another. Saving the state means that Emacs starts up with
1870 the same set of buffers, major modes, buffer positions, and so on that
1871 the previous Emacs session had.
1873 @vindex desktop-enable
1874 To use Desktop, you should use the Customization buffer (@pxref{Easy
1875 Customization}) to set @code{desktop-enable} to a non-@code{nil} value,
1876 or add these lines at the end of your @file{.emacs} file:
1879 (desktop-load-default)
1884 @findex desktop-save
1885 The first time you save the state of the Emacs session, you must do it
1886 manually, with the command @kbd{M-x desktop-save}. Once you have done
1887 that, exiting Emacs will save the state again---not only the present
1888 Emacs session, but also subsequent sessions. You can also save the
1889 state at any time, without exiting Emacs, by typing @kbd{M-x
1890 desktop-save} again.
1892 In order for Emacs to recover the state from a previous session, you
1893 must start it with the same current directory as you used when you
1894 started the previous session. This is because @code{desktop-read} looks
1895 in the current directory for the file to read. This means that you can
1896 have separate saved sessions in different directories; the directory in
1897 which you start Emacs will control which saved session to use.
1899 @vindex desktop-files-not-to-save
1900 The variable @code{desktop-files-not-to-save} controls which files are
1901 excluded from state saving. Its value is a regular expression that
1902 matches the files to exclude. By default, remote (ftp-accessed) files
1903 are excluded; this is because visiting them again in the subsequent
1904 session would be slow. If you want to include these files in state
1905 saving, set @code{desktop-files-not-to-save} to @code{"^$"}.
1906 @xref{Remote Files}.
1910 @findex toggle-save-place
1911 The Saveplace library provides a simpler feature that records your
1912 position in each file when you kill its buffer (or kill Emacs), and
1913 jumps to the same position when you visit the file again (even in
1914 another Emacs session). Use @kbd{M-x toggle-save-place} to turn on
1915 place-saving in a given file. Customize the option @code{save-place}
1916 to turn it on for all files in each session.
1918 @node Recursive Edit, Emulation, Saving Emacs Sessions, Top
1919 @section Recursive Editing Levels
1920 @cindex recursive editing level
1921 @cindex editing level, recursive
1923 A @dfn{recursive edit} is a situation in which you are using Emacs
1924 commands to perform arbitrary editing while in the middle of another
1925 Emacs command. For example, when you type @kbd{C-r} inside of a
1926 @code{query-replace}, you enter a recursive edit in which you can change
1927 the current buffer. On exiting from the recursive edit, you go back to
1928 the @code{query-replace}.
1931 @findex exit-recursive-edit
1932 @cindex exiting recursive edit
1933 @dfn{Exiting} the recursive edit means returning to the unfinished
1934 command, which continues execution. The command to exit is @kbd{C-M-c}
1935 (@code{exit-recursive-edit}).
1937 You can also @dfn{abort} the recursive edit. This is like exiting,
1938 but also quits the unfinished command immediately. Use the command
1939 @kbd{C-]} (@code{abort-recursive-edit}) to do this. @xref{Quitting}.
1941 The mode line shows you when you are in a recursive edit by displaying
1942 square brackets around the parentheses that always surround the major and
1943 minor mode names. Every window's mode line shows this in the same way,
1944 since being in a recursive edit is true of Emacs as a whole rather than
1945 any particular window or buffer.
1947 It is possible to be in recursive edits within recursive edits. For
1948 example, after typing @kbd{C-r} in a @code{query-replace}, you may type a
1949 command that enters the debugger. This begins a recursive editing level
1950 for the debugger, within the recursive editing level for @kbd{C-r}.
1951 Mode lines display a pair of square brackets for each recursive editing
1952 level currently in progress.
1954 Exiting the inner recursive edit (such as, with the debugger @kbd{c}
1955 command) resumes the command running in the next level up. When that
1956 command finishes, you can then use @kbd{C-M-c} to exit another recursive
1957 editing level, and so on. Exiting applies to the innermost level only.
1958 Aborting also gets out of only one level of recursive edit; it returns
1959 immediately to the command level of the previous recursive edit. If you
1960 wish, you can then abort the next recursive editing level.
1962 Alternatively, the command @kbd{M-x top-level} aborts all levels of
1963 recursive edits, returning immediately to the top-level command reader.
1965 The text being edited inside the recursive edit need not be the same text
1966 that you were editing at top level. It depends on what the recursive edit
1967 is for. If the command that invokes the recursive edit selects a different
1968 buffer first, that is the buffer you will edit recursively. In any case,
1969 you can switch buffers within the recursive edit in the normal manner (as
1970 long as the buffer-switching keys have not been rebound). You could
1971 probably do all the rest of your editing inside the recursive edit,
1972 visiting files and all. But this could have surprising effects (such as
1973 stack overflow) from time to time. So remember to exit or abort the
1974 recursive edit when you no longer need it.
1976 In general, we try to minimize the use of recursive editing levels in
1977 GNU Emacs. This is because they constrain you to ``go back'' in a
1978 particular order---from the innermost level toward the top level. When
1979 possible, we present different activities in separate buffers so that
1980 you can switch between them as you please. Some commands switch to a
1981 new major mode which provides a command to switch back. These
1982 approaches give you more flexibility to go back to unfinished tasks in
1983 the order you choose.
1985 @node Emulation, Hyperlinking, Recursive Edit, Top
1987 @cindex emulating other editors
1988 @cindex other editors
1991 @cindex PC key bindings
1992 @cindex scrolling all windows
1993 @cindex PC selection
1994 @cindex Motif key bindings
1995 @cindex Macintosh key bindings
1998 GNU Emacs can be programmed to emulate (more or less) most other
1999 editors. Standard facilities can emulate these:
2002 @item CRiSP/Brief (PC editor)
2004 @vindex crisp-override-meta-x
2005 @findex scroll-all-mode
2007 @cindex Brief emulation
2008 @cindex emulation of Brief
2010 You can turn on key bindings to emulate the CRiSP/Brief editor with
2011 @kbd{M-x crisp-mode}. Note that this rebinds @kbd{M-x} to exit Emacs
2012 unless you change the user option @code{crisp-override-meta-x}. You can
2013 also use the command @kbd{M-x scroll-all-mode} or set the user option
2014 @code{crisp-load-scroll-all} to emulate CRiSP's scroll-all feature
2015 (scrolling all windows together).
2017 @item EDT (DEC VMS editor)
2018 @findex edt-emulation-on
2019 @findex edt-emulation-off
2020 Turn on EDT emulation with @kbd{M-x edt-emulation-on}. @kbd{M-x
2021 edt-emulation-off} restores normal Emacs command bindings.
2023 Most of the EDT emulation commands are keypad keys, and most standard
2024 Emacs key bindings are still available. The EDT emulation rebindings
2025 are done in the global keymap, so there is no problem switching
2026 buffers or major modes while in EDT emulation.
2028 @item ``PC'' bindings
2029 @findex pc-bindings-mode
2030 @cindex ``PC'' key bindings
2031 The command @kbd{M-x pc-bindings-mode} sets up certain key bindings
2032 for ``PC compatibility''---what people are often used to on PCs---as
2033 follows: @kbd{Delete} and its variants delete forward instead of
2034 backward, @kbd{C-Backspace} kills backward a word (as @kbd{C-Delete}
2035 normally would), @kbd{M-Backspace} does undo, @kbd{Home} and @kbd{End}
2036 move to beginning and end of line, @kbd{C-Home} and @kbd{C-End} move
2037 to beginning and end of buffer and @kbd{C-Escape} does
2038 @code{list-buffers}.
2040 @item PC Selection mode
2041 @findex pc-selection-mode
2042 @cindex PC Selection minor mode
2043 @cindex mode, PC selection
2044 @cindex selection, PC
2045 The command @kbd{M-x pc-selection-mode} toggles a global minor mode
2046 that emulates the mark, copy, cut and paste commands of various other
2047 systems---an interface known as CUA. It establishes the key bindings
2048 of PC mode, and also modifies the bindings of the cursor keys and the
2049 @kbd{next}, @kbd{prior}, @kbd{home} and @kbd{end} keys. It does not
2050 provide the full set of CUA key bindings---the fundamental Emacs keys
2051 @kbd{C-c}, @kbd{C-v} and @kbd{C-x} are not changed.
2053 The standard keys for moving around (@kbd{right}, @kbd{left},
2054 @kbd{up}, @kbd{down}, @kbd{home}, @kbd{end}, @kbd{prior}, @kbd{next},
2055 called ``move-keys'') deactivate the mark in PC selection mode.
2056 However, using @kbd{Shift} together with the ``move keys'' activates
2057 the region over which they move. The copy, cut and paste functions
2058 are available on @kbd{C-insert}, @kbd{S-delete} and @kbd{S-insert}
2061 Turning @code{pc-selection-mode} off restores the old key bindings of
2064 @cindex s-region package
2065 The @code{s-region} package provides similar, but less complete,
2068 @item TPU (DEC VMS editor)
2071 @kbd{M-x tpu-edt-on} turns on emulation of the TPU editor emulating EDT.
2073 @item vi (Berkeley editor)
2075 Viper is the newest emulator for vi. It implements several levels of
2076 emulation; level 1 is closest to vi itself, while level 5 departs
2077 somewhat from strict emulation to take advantage of the capabilities of
2078 Emacs. To invoke Viper, type @kbd{M-x viper-mode}; it will guide you
2079 the rest of the way and ask for the emulation level. @inforef{Top,
2082 @item vi (another emulator)
2084 @kbd{M-x vi-mode} enters a major mode that replaces the previously
2085 established major mode. All of the vi commands that, in real vi, enter
2086 ``input'' mode are programmed instead to return to the previous major
2087 mode. Thus, ordinary Emacs serves as vi's ``input'' mode.
2089 Because vi emulation works through major modes, it does not work
2090 to switch buffers during emulation. Return to normal Emacs first.
2092 If you plan to use vi emulation much, you probably want to bind a key
2093 to the @code{vi-mode} command.
2095 @item vi (alternate emulator)
2097 @kbd{M-x vip-mode} invokes another vi emulator, said to resemble real vi
2098 more thoroughly than @kbd{M-x vi-mode}. ``Input'' mode in this emulator
2099 is changed from ordinary Emacs so you can use @key{ESC} to go back to
2100 emulated vi command mode. To get from emulated vi command mode back to
2101 ordinary Emacs, type @kbd{C-z}.
2103 This emulation does not work through major modes, and it is possible
2104 to switch buffers in various ways within the emulator. It is not
2105 so necessary to assign a key to the command @code{vip-mode} as
2106 it is with @code{vi-mode} because terminating insert mode does
2109 @inforef{Top, VIP, vip}, for full information.
2111 @item WordStar (old wordprocessor)
2112 @findex wordstar-mode
2113 @kbd{M-x wordstar-mode} provides a major mode with WordStar-like
2117 @node Hyperlinking, Dissociated Press, Emulation, Top
2118 @section Hyperlinking and Navigation Features
2120 @cindex hyperlinking
2122 Various modes documented elsewhere have hypertext features so that
2123 you can follow links, usually by clicking @kbd{Mouse-2} on the link or
2124 typing @key{RET} while point is on the link. Info mode, Help mode and
2125 the Dired-like modes are examples. The Tags facility links between
2126 uses and definitions in source files, see @ref{Tags}. Imenu provides
2127 navigation amongst items indexed in the current buffer, see
2128 @ref{Imenu}. Info-lookup provides mode-specific lookup of definitions
2129 in Info indexes, see @ref{Documentation}. Speedbar maintains a frame
2130 in which links to files, and locations in files are displayed, see
2133 Other non-mode-specific facilities described in this section enable
2134 following links from the current buffer in a context-sensitive
2138 * Browse-URL:: Following URLs.
2139 * Goto-address:: Activating URLs.
2140 * FFAP:: Finding files etc. at point.
2141 * Find-func:: Finding function and variable definitions.
2145 @subsection Following URLs
2146 @cindex World Wide Web
2149 @findex browse-url-at-point
2150 @findex browse-url-at-mouse
2155 @item M-x browse-url @key{RET} @var{url} @key{RET}
2156 Load a URL into a Web browser.
2159 The Browse-URL package provides facilities for following URLs specifying
2160 links on the World Wide Web. Usually this works by invoking a web
2161 browser, but you can, for instance, arrange to invoke @code{compose-mail}
2162 from @samp{mailto:} URLs.
2164 The general way to use this feature is to type @kbd{M-x browse-url},
2165 which displays a specified URL. If point is located near a plausible
2166 URL, that URL is used as the default. Other commands are available
2167 which you might like to bind to keys, such as
2168 @code{browse-url-at-point} and @code{browse-url-at-mouse}.
2170 @vindex browse-url-browser-function
2171 You can customize Browse-URL's behavior via various options in the
2172 @code{browse-url} Customize group, particularly
2173 @code{browse-url-browser-function}. You can invoke actions dependent
2174 on the type of URL by defining @code{browse-url-browser-function} as
2175 an association list. The package's commentary available via @kbd{C-h
2176 p} provides more information. Packages with facilities for following
2177 URLs should always go through Browse-URL, so that the customization
2178 options for Browse-URL will affect all browsing in Emacs.
2181 @subsection Activating URLs
2182 @findex goto-address
2183 @cindex Goto-address
2184 @cindex URLs, activating
2187 @item M-x goto-address
2188 Activate URLs and e-mail addresses in the current buffer.
2191 You can make URLs in the current buffer active with @kbd{M-x
2192 goto-address}. This finds all the URLs in the buffer, and establishes
2193 bindings for @kbd{Mouse-2} and @kbd{C-c @key{RET}} on them. After
2194 activation, if you click on a URL with @kbd{Mouse-2}, or move to a URL
2195 and type @kbd{C-c @key{RET}}, that will display the web page that the URL
2196 specifies. For a @samp{mailto} URL, it sends mail instead, using your
2197 selected mail-composition method (@pxref{Mail Methods}).
2199 It can be useful to add @code{goto-address} to mode hooks and the
2200 hooks used to display an incoming message.
2201 @code{rmail-show-message-hook} is the appropriate hook for Rmail, and
2202 @code{mh-show-mode-hook} for MH-E. This is not needed for Gnus,
2203 which has a similar feature of its own.
2207 @subsection Finding Files and URLs at Point
2208 @findex find-file-at-point
2210 @findex ffap-dired-at-point
2213 @cindex finding file at point
2215 FFAP mode replaces certain key bindings for finding files, including
2216 @kbd{C-x C-f}, with commands that provide more sensitive defaults.
2217 These commands behave like the ordinary ones when given a prefix
2218 argument. Otherwise, they get the default file name or URL from the
2219 text around point. If what is found in the buffer has the form of a
2220 URL rather than a file name, the commands use @code{browse-url} to
2223 This feature is useful for following references in mail or news
2224 buffers, @file{README} files, @file{MANIFEST} files, and so on. The
2225 @samp{ffap} package's commentary available via @kbd{C-h p} and the
2226 @code{ffap} Custom group provide details.
2228 @cindex FFAP minor mode
2230 You can turn on FFAP minor mode to make the following key bindings
2231 and to install hooks for using @code{ffap} in Rmail, Gnus and VM
2235 @item C-x C-f @var{filename} @key{RET}
2236 @kindex C-x C-f @r{(FFAP)}
2237 Find @var{filename}, guessing a default from text around point
2238 (@code{find-file-at-point}).
2240 @kindex C-x 4 f @r{(FFAP)}
2241 @code{ffap-other-window}, analogous to @code{find-file-other-window}.
2243 @kindex C-x 5 f @r{(FFAP)}
2244 @code{ffap-other-frame}, analogous to @code{find-file-other-frame}.
2246 Search buffer for next file name or URL, then find that file or URL.
2247 @item C-x d @var{directory} @key{RET}
2248 @kindex C-x d @r{(FFAP)}
2249 Start Dired on @var{directory}, defaulting to the directory name at
2250 point (@code{ffap-dired-at-point}).
2252 @kindex S-Mouse-3 @r{(FFAP)}
2253 @code{ffap-at-mouse} finds the file guessed from text around the position
2256 @kindex C-S-Mouse-3 @r{(FFAP)}
2257 Display a menu of files and URLs mentioned in current buffer, then
2258 find the one you select (@code{ffap-menu}).
2262 @subsection Finding Function and Variable Definitions
2263 @cindex definitions, finding in Lisp sources
2264 @cindex Lisp definitions, finding in sources
2267 @item M-x find-function @key{RET} @var{function} @key{RET}
2268 Find the definition of @var{function} in its source file.
2269 @item M-x find-variable @key{RET} @var{variable} @key{RET}
2270 Find the definition of @var{variable} in its source file.
2271 @item M-x find-function-on-key @key{RET} @var{key}
2272 Find the definition of the function that @var{key} invokes.
2275 These commands provide an easy way to find the definitions of Emacs
2276 Lisp functions and variables. They are similar in purpose to the Tags
2277 facility (@pxref{Tags}), but don't require a tags table; on the other
2278 hand, they only work for function and variable definitions that are
2279 already loaded in the Emacs session.
2281 @findex find-function
2282 @findex find-function-on-key
2283 @findex find-variable
2284 To find the definition of a function, use @kbd{M-x find-function}.
2285 @kbd{M-x find-variable} finds the definition of a specified variable.
2286 @kbd{M-x find-function-on-key} finds the definition of the function
2287 bound to a specified key.
2289 To use these commands, you must have the Lisp source (@samp{.el})
2290 files available along with the compiled (@samp{.elc}) files, in
2291 directories in @code{load-path}. You can use compressed source files
2292 if you enable Auto Compression mode. These commands only handle
2293 definitions written in Lisp, not primitive functions or variables
2294 defined in the C code of Emacs.
2296 @node Dissociated Press, Amusements, Hyperlinking, Top
2297 @section Dissociated Press
2299 @findex dissociated-press
2300 @kbd{M-x dissociated-press} is a command for scrambling a file of text
2301 either word by word or character by character. Starting from a buffer of
2302 straight English, it produces extremely amusing output. The input comes
2303 from the current Emacs buffer. Dissociated Press writes its output in a
2304 buffer named @samp{*Dissociation*}, and redisplays that buffer after every
2305 couple of lines (approximately) so you can read the output as it comes out.
2307 Dissociated Press asks every so often whether to continue generating
2308 output. Answer @kbd{n} to stop it. You can also stop at any time by
2309 typing @kbd{C-g}. The dissociation output remains in the
2310 @samp{*Dissociation*} buffer for you to copy elsewhere if you wish.
2312 @cindex presidentagon
2313 Dissociated Press operates by jumping at random from one point in the
2314 buffer to another. In order to produce plausible output rather than
2315 gibberish, it insists on a certain amount of overlap between the end of
2316 one run of consecutive words or characters and the start of the next.
2317 That is, if it has just output `president' and then decides to jump
2318 to a different point in the file, it might spot the `ent' in `pentagon'
2319 and continue from there, producing `presidentagon'.@footnote{This
2320 dissociword actually appeared during the Vietnam War, when it was very
2321 appropriate.} Long sample texts produce the best results.
2323 @cindex againformation
2324 A positive argument to @kbd{M-x dissociated-press} tells it to operate
2325 character by character, and specifies the number of overlap characters. A
2326 negative argument tells it to operate word by word and specifies the number
2327 of overlap words. In this mode, whole words are treated as the elements to
2328 be permuted, rather than characters. No argument is equivalent to an
2329 argument of two. For your againformation, the output goes only into the
2330 buffer @samp{*Dissociation*}. The buffer you start with is not changed.
2332 @cindex Markov chain
2334 @cindex techniquitous
2335 Dissociated Press produces nearly the same results as a Markov chain
2336 based on a frequency table constructed from the sample text. It is,
2337 however, an independent, ignoriginal invention. Dissociated Press
2338 techniquitously copies several consecutive characters from the sample
2339 between random choices, whereas a Markov chain would choose randomly for
2340 each word or character. This makes for more plausible sounding results,
2347 @cindex developediment
2349 It is a mustatement that too much use of Dissociated Press can be a
2350 developediment to your real work. Sometimes to the point of outragedy.
2351 And keep dissociwords out of your documentation, if you want it to be well
2352 userenced and properbose. Have fun. Your buggestions are welcome.
2354 @node Amusements, Customization, Dissociated Press, Top
2355 @section Other Amusements
2360 @cindex tower of Hanoi
2362 If you are a little bit bored, you can try @kbd{M-x hanoi}. If you are
2363 considerably bored, give it a numeric argument. If you are very, very
2364 bored, try an argument of 9. Sit back and watch.
2367 If you want a little more personal involvement, try @kbd{M-x gomoku},
2368 which plays the game Go Moku with you.
2374 @kbd{M-x blackbox}, @kbd{M-x mpuz} and @kbd{M-x 5x5} are kinds of puzzles.
2375 @code{blackbox} challenges you to determine the location of objects
2376 inside a box by tomography. @code{mpuz} displays a multiplication
2377 puzzle with letters standing for digits in a code that you must
2378 guess---to guess a value, type a letter and then the digit you think it
2379 stands for. The aim of @code{5x5} is to fill in all the squares.
2383 @cindex cryptanalysis
2384 @kbd{M-x decipher} helps you to cryptanalyze a buffer which is encrypted
2385 in a simple monoalphabetic substitution cipher.
2388 @kbd{M-x dunnet} runs an adventure-style exploration game, which is
2389 a bigger sort of puzzle.
2392 @cindex landmark game
2393 @kbd{M-x lm} runs a relatively non-participatory game in which a robot
2394 attempts to maneuver towards a tree at the center of the window based on
2395 unique olfactory cues from each of the four directions.
2399 @kbd{M-x life} runs Conway's ``Life'' cellular automaton.
2401 @findex morse-region
2402 @findex unmorse-region
2404 @cindex --/---/.-./.../.
2405 @kbd{M-x morse-region} converts text in a region to Morse code and
2406 @kbd{M-x unmorse-region} converts it back. No cause for remorse.
2410 @kbd{M-x pong} plays a Pong-like game, bouncing the ball off opposing
2415 @kbd{M-x solitaire} plays a game of solitaire in which you jump pegs
2418 @findex studlify-region
2420 @kbd{M-x studlify-region} studlify-cases the region, producing
2424 M-x stUdlIfY-RegioN stUdlIfY-CaSeS thE region.
2431 @kbd{M-x tetris} runs an implementation of the well-known Tetris game.
2432 Likewise, @kbd{M-x snake} provides an implementation of Snake.
2434 When you are frustrated, try the famous Eliza program. Just do
2435 @kbd{M-x doctor}. End each input by typing @key{RET} twice.
2438 When you are feeling strange, type @kbd{M-x yow}.
2441 The command @kbd{M-x zone} plays games with the display when Emacs is