1 @c This is part of the Emacs manual.
2 @c Copyright (C) 1985-1987, 1993-1995, 1997, 2000-2015 Free Software
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 Usenet news, host and network security,
10 viewing PDFs and other such documents, web
11 browsing, running shell commands and shell subprocesses, using a
12 single shared Emacs for utilities that expect to run an editor as a
13 subprocess, printing, sorting text, editing binary files, saving an
14 Emacs session for later resumption, recursive editing level, following
15 hyperlinks, and various diversions and amusements.
29 Gnus is an Emacs package primarily designed for reading and posting
30 Usenet news. It can also be used to read and respond to messages from
31 a number of other sources---email, remote directories, digests, and so
32 on. Here we introduce Gnus and describe several basic features.
34 For full details, see @ref{Top, Gnus,, gnus, The Gnus Manual}.
37 For full details on Gnus, type @kbd{C-h i} and then select the Gnus
42 * Buffers of Gnus:: The group, summary, and article buffers.
43 * Gnus Startup:: What you should know about starting Gnus.
44 * Gnus Group Buffer:: A short description of Gnus group commands.
45 * Gnus Summary Buffer:: A short description of Gnus summary commands.
49 @subsection Gnus Buffers
51 Gnus uses several buffers to display information and to receive
52 commands. The three most commonly-used Gnus buffers are the
53 @dfn{group buffer}, the @dfn{summary buffer} and the @dfn{article
56 The @dfn{group buffer} contains a list of article sources (e.g.,
57 newsgroups and email inboxes), which are collectively referred to as
58 @dfn{groups}. This is the first buffer Gnus displays when it starts
59 up. It normally displays only the groups to which you subscribe and
60 that contain unread articles. From this buffer, you can select a
63 The @dfn{summary buffer} lists the articles in a single group,
64 showing one article per line. By default, it displays each article's
65 author, subject, and line
70 number, but this is customizable; @xref{Summary Buffer Format,,, gnus,
73 The summary buffer is created when you select a group in the group
74 buffer, and is killed when you exit the group.
76 From the summary buffer, you can choose an article to view. The
77 article is displayed in the @dfn{article buffer}. In normal Gnus
78 usage, you view this buffer but do not select it---all useful Gnus
79 commands can be invoked from the summary buffer. But you can select
80 the article buffer, and execute Gnus commands from it, if you wish.
83 @subsection When Gnus Starts Up
86 @cindex @file{.newsrc} file
87 If your system has been set up for reading Usenet news, getting
88 started with Gnus is easy---just type @kbd{M-x gnus}.
90 On starting up, Gnus reads your @dfn{news initialization file}: a
91 file named @file{.newsrc} in your home directory which lists your
92 Usenet newsgroups and subscriptions (this file is not unique to Gnus;
93 it is used by many other newsreader programs). It then tries to
94 contact the system's default news server, which is typically specified
95 by the @env{NNTPSERVER} environment variable.
97 If your system does not have a default news server, or if you wish
98 to use Gnus for reading email, then before invoking @kbd{M-x gnus} you
99 need to tell Gnus where to get news and/or mail. To do this,
100 customize the variables @code{gnus-select-method} and/or
101 @code{gnus-secondary-select-methods}.
103 See the Gnus manual for details.
106 @xref{Finding the News,,, gnus, The Gnus Manual}.
109 Once Gnus has started up, it displays the group buffer. By default,
110 the group buffer shows only a small number of @dfn{subscribed groups}.
111 Groups with other statuses---@dfn{unsubscribed}, @dfn{killed}, or
112 @dfn{zombie}---are hidden. The first time you start Gnus, any group
113 to which you are not subscribed is made into a killed group; any group
114 that subsequently appears on the news server becomes a zombie group.
116 To proceed, you must select a group in the group buffer to open the
117 summary buffer for that group; then, select an article in the summary
118 buffer to view its article buffer in a separate window. The following
119 sections explain how to use the group and summary buffers to do this.
121 To quit Gnus, type @kbd{q} in the group buffer. This automatically
122 records your group statuses in the files @file{.newsrc} and
123 @file{.newsrc.eld}, so that they take effect in subsequent Gnus
126 @node Gnus Group Buffer
127 @subsection Using the Gnus Group Buffer
129 The following commands are available in the Gnus group buffer:
132 @kindex SPC @r{(Gnus Group mode)}
133 @findex gnus-group-read-group
135 Switch to the summary buffer for the group on the current line.
137 @kindex l @r{(Gnus Group mode)}
138 @kindex A s @r{(Gnus Group mode)}
139 @findex gnus-group-list-groups
142 In the group buffer, list only the groups to which you subscribe and
143 which contain unread articles (this is the default listing).
145 @kindex L @r{(Gnus Group mode)}
146 @kindex A u @r{(Gnus Group mode)}
147 @findex gnus-group-list-all-groups
150 List all subscribed and unsubscribed groups, but not killed or zombie
153 @kindex A k @r{(Gnus Group mode)}
154 @findex gnus-group-list-all-groups
158 @kindex A z @r{(Gnus Group mode)}
159 @findex gnus-group-list-all-groups
163 @kindex u @r{(Gnus Group mode)}
164 @findex gnus-group-unsubscribe-current-group
165 @cindex subscribe groups
166 @cindex unsubscribe groups
168 Toggle the subscription status of the group on the current line
169 (i.e., turn a subscribed group into an unsubscribed group, or vice
170 versa). Invoking this on a killed or zombie group turns it into an
173 @kindex C-k @r{(Gnus Group mode)}
174 @findex gnus-group-kill-group
176 Kill the group on the current line. Killed groups are not recorded in
177 the @file{.newsrc} file, and they are not shown in the @kbd{l} or
180 @kindex DEL @r{(Gnus Group mode)}
182 Move point to the previous group containing unread articles.
184 @kindex n @r{(Gnus Group mode)}
185 @findex gnus-group-next-unread-group
186 @findex gnus-summary-next-unread-article
188 Move point to the next unread group.
190 @kindex p @r{(Gnus Group mode)}
191 @findex gnus-group-prev-unread-group
192 @findex gnus-summary-prev-unread-article
194 Move point to the previous unread group.
196 @kindex q @r{(Gnus Group mode)}
197 @findex gnus-group-exit
199 Update your Gnus settings, and quit Gnus.
202 @node Gnus Summary Buffer
203 @subsection Using the Gnus Summary Buffer
205 The following commands are available in the Gnus summary buffer:
208 @kindex SPC @r{(Gnus Summary mode)}
209 @findex gnus-group-read-group
211 If there is no article selected, select the article on the current
212 line and display its article buffer. Otherwise, try scrolling the
213 selected article buffer in its window; on reaching the end of the
214 buffer, select the next unread article.
216 Thus, you can read through all articles by repeatedly typing
219 @kindex DEL @r{(Gnus Summary mode)}
220 @findex gnus-summary-prev-page
222 Scroll the text of the article backwards.
224 @kindex n @r{(Gnus Summary mode)}
225 @findex gnus-group-next-unread-group
226 @findex gnus-summary-next-unread-article
228 Select the next unread article.
230 @kindex p @r{(Gnus Summary mode)}
231 @findex gnus-group-prev-unread-group
232 @findex gnus-summary-prev-unread-article
234 Select the previous unread article.
236 @kindex s @r{(Gnus Summary mode)}
237 @findex gnus-summary-isearch-article
239 Do an incremental search on the selected article buffer, as if you
240 switched to the buffer and typed @kbd{C-s} (@pxref{Incremental
243 @kindex M-s @r{(Gnus Summary mode)}
244 @findex gnus-summary-search-article-forward
245 @item M-s @var{regexp} @key{RET}
246 Search forward for articles containing a match for @var{regexp}.
248 @kindex q @r{(Gnus Summary mode)}
250 Exit the summary buffer and return to the group buffer.
254 @section Host Security
257 Emacs runs inside an operating system such as GNU/Linux, and relies on
258 the operating system to check security constraints such as accesses to
259 files. The default settings for Emacs are designed for typical use;
260 they may require some tailoring in environments where security is more
261 of a concern, or less of a concern, than usual. For example,
262 file-local variables can be risky, and you can set the variable
263 @code{enable-local-variables} to @code{:safe} or (even more
264 conservatively) to @code{nil}; conversely, if your files can all be
265 trusted and the default checking for these variables is irritating,
266 you can set @code{enable-local-variables} to @code{:all}. @xref{Safe
269 @xref{Security Considerations,,, elisp, The Emacs Lisp Reference
270 Manual}, for more information about security considerations when using
271 Emacs as part of a larger application.
273 @node Network Security
274 @section Network Security
275 @cindex network security manager
282 Whenever Emacs establishes any network connection, it passes the
283 established connection to the @dfn{Network Security Manager}
284 (@acronym{NSM}). @acronym{NSM} is responsible for enforcing the
285 network security under your control.
287 @vindex network-security-level
288 The @code{network-security-level} variable determines the security
289 level that @acronym{NSM} enforces. If its value is @code{low}, no
290 security checks are performed.
292 If this variable is @code{medium} (which is the default), a number of
293 checks will be performed. If as result @acronym{NSM} determines that
294 the network connection might not be trustworthy, it will make you
295 aware of that, and will ask you what to do about the network
298 You can decide to register a permanent security exception for an
299 unverified connection, a temporary exception, or refuse the connection
302 Below is a list of the checks done on the @code{medium} level.
306 @item unable to verify a @acronym{TLS} certificate
307 If the connection is a @acronym{TLS}, @acronym{SSL} or
308 @acronym{STARTTLS} connection, @acronym{NSM} will check whether
309 the certificate used to establish the identity of the server we're
310 connecting to can be verified.
312 While an invalid certificate is often the cause for concern (there
313 could be a Man-in-the-Middle hijacking your network connection and
314 stealing your password), there may be valid reasons for going ahead
315 with the connection anyway. For instance, the server may be using a
316 self-signed certificate, or the certificate may have expired. It's up
317 to you to determine whether it's acceptable to continue with the
320 @item a self-signed certificate has changed
321 If you've previously accepted a self-signed certificate, but it has
322 now changed, that could mean that the server has just changed the
323 certificate, but it might also mean that the network connection has
326 @item previously encrypted connection now unencrypted
327 If the connection is unencrypted, but it was encrypted in previous
328 sessions, this might mean that there is a proxy between you and the
329 server that strips away @acronym{STARTTLS} announcements, leaving the
330 connection unencrypted. This is usually very suspicious.
332 @item talking to an unencrypted service when sending a password
333 When connecting to an @acronym{IMAP} or @acronym{POP3} server, these
334 should usually be encrypted, because it's common to send passwords
335 over these connections. Similarly, if you're sending email via
336 @acronym{SMTP} that requires a password, you usually want that
337 connection to be encrypted. If the connection isn't encrypted,
338 @acronym{NSM} will warn you.
342 If @code{network-security-level} is @code{high}, the following checks
343 will be made, in addition to the above:
346 @item a validated certificate changes the public key
347 Servers change their keys occasionally, and that is normally nothing
348 to be concerned about. However, if you are worried that your network
349 connections are being hijacked by agencies who have access to pliable
350 Certificate Authorities which issue new certificates for third-party
351 services, you may want to keep track of these changes.
353 @item Diffie-Hellman low prime bits
354 When doing the public key exchange, the number of prime bits
355 should be high to ensure that the channel can't be eavesdropped on by
356 third parties. If this number is too low, you will be warned.
358 @item @acronym{RC4} stream cipher
359 The @acronym{RC4} stream cipher is believed to be of low quality and
360 may allow eavesdropping by third parties.
362 @item @acronym{SSL1}, @acronym{SSL2} and @acronym{SSL3}
363 The protocols older than @acronym{TLS1.0} are believed to be
364 vulnerable to a variety of attacks, and you may want to avoid using
365 these if what you're doing requires higher security.
368 Finally, if @code{network-security-level} is @code{paranoid}, you will
369 also be notified the first time @acronym{NSM} sees any new
370 certificate. This will allow you to inspect all the certificates from
371 all the connections that Emacs makes.
373 The following additional variables can be used to control details of
374 @acronym{NSM} operation:
377 @item nsm-settings-file
378 @vindex nsm-settings-file
379 This is the file where @acronym{NSM} stores details about connections.
380 It defaults to @file{~/.emacs.d/network-security.data}.
382 @item nsm-save-host-names
383 @vindex nsm-save-host-names
384 By default, host names will not be saved for non-@code{STARTTLS}
385 connections. Instead a host/port hash is used to identify connections.
386 This means that one can't casually read the settings file to see what
387 servers the user has connected to. If this variable is @code{t},
388 @acronym{NSM} will also save host names in the nsm-settings-file.
393 @section Document Viewing
397 @cindex PostScript file
398 @cindex OpenDocument file
399 @cindex Microsoft Office file
401 @cindex mode, DocView
402 @cindex document viewer (DocView)
403 @findex doc-view-mode
405 DocView mode is a major mode for viewing DVI, PostScript (PS), PDF,
406 OpenDocument, and Microsoft Office documents. It provides features
407 such as slicing, zooming, and searching inside documents. It works by
408 converting the document to a set of images using the @command{gs}
409 (GhostScript) or @command{mudraw}/@command{pdfdraw} (MuPDF) commands
410 and other external tools @footnote{For PostScript files, GhostScript
411 is a hard requirement. For DVI files, @code{dvipdf} or @code{dvipdfm}
412 is needed. For OpenDocument and Microsoft Office documents, the
413 @code{unoconv} tool is needed.}, and displaying those images.
415 @findex doc-view-toggle-display
416 @findex doc-view-toggle-display
417 @cindex doc-view-minor-mode
418 When you visit a document file that can be displayed with DocView
419 mode, Emacs automatically uses DocView mode @footnote{The needed
420 external tools for the document type must be available, and Emacs must
421 be running in a graphical frame and have PNG image support. If any of
422 these requirements is not fulfilled, Emacs falls back to another major
423 mode.}. As an exception, when you visit a PostScript file, Emacs
424 switches to PS mode, a major mode for editing PostScript files as
425 text; however, it also enables DocView minor mode, so you can type
426 @kbd{C-c C-c} to view the document with DocView. In either DocView
427 mode or DocView minor mode, repeating @kbd{C-c C-c}
428 (@code{doc-view-toggle-display}) toggles between DocView and the
429 underlying file contents.
431 @findex doc-view-open-text
432 When you visit a file which would normally be handled by DocView
433 mode but some requirement is not met (e.g., you operate in a terminal
434 frame or emacs has no PNG support), you are queried if you want to
435 view the document's contents as plain text. If you confirm, the
436 buffer is put in text mode and DocView minor mode is activated. Thus,
437 by typing @kbd{C-c C-c} you switch to the fallback mode. With another
438 @kbd{C-c C-c} you return to DocView mode. The plain text contents can
439 also be displayed from within DocView mode by typing @kbd{C-c C-t}
440 (@code{doc-view-open-text}).
442 You can explicitly enable DocView mode with the command @code{M-x
443 doc-view-mode}. You can toggle DocView minor mode with @code{M-x
444 doc-view-minor-mode}.
446 When DocView mode starts, it displays a welcome screen and begins
447 formatting the file, page by page. It displays the first page once
448 that has been formatted.
450 To kill the DocView buffer, type @kbd{k}
451 (@code{doc-view-kill-proc-and-buffer}). To bury it, type @kbd{q}
452 (@code{quit-window}).
455 * Navigation: DocView Navigation. Navigating DocView buffers.
456 * Searching: DocView Searching. Searching inside documents.
457 * Slicing: DocView Slicing. Specifying which part of a page is displayed.
458 * Conversion: DocView Conversion. Influencing and triggering conversion.
461 @node DocView Navigation
462 @subsection DocView Navigation
464 In DocView mode, you can scroll the current page using the usual
465 Emacs movement keys: @kbd{C-p}, @kbd{C-n}, @kbd{C-b}, @kbd{C-f}, and
468 @vindex doc-view-continuous
469 By default, the line-motion keys @kbd{C-p} and @kbd{C-n} stop
470 scrolling at the beginning and end of the current page, respectively.
471 However, if you change the variable @code{doc-view-continuous} to a
472 non-@code{nil} value, then @kbd{C-p} displays the previous page if you
473 are already at the beginning of the current page, and @kbd{C-n}
474 displays the next page if you are at the end of the current page.
476 @findex doc-view-next-page
477 @findex doc-view-previous-page
478 @kindex n @r{(DocView mode)}
479 @kindex p @r{(DocView mode)}
480 @kindex C-x ] @r{(DocView mode)}
481 @kindex C-x [ @r{(DocView mode)}
482 You can also display the next page by typing @kbd{n}, @key{next} or
483 @kbd{C-x ]} (@code{doc-view-next-page}). To display the previous
484 page, type @kbd{p}, @key{prior} or @kbd{C-x [}
485 (@code{doc-view-previous-page}).
487 @findex doc-view-scroll-up-or-next-page
488 @findex doc-view-scroll-down-or-previous-page
489 @kindex SPC @r{(DocView mode)}
490 @kindex DEL @r{(DocView mode)}
491 @key{SPC} (@code{doc-view-scroll-up-or-next-page}) is a convenient
492 way to advance through the document. It scrolls within the current
493 page or advances to the next. @key{DEL} moves backwards in a similar
494 way (@code{doc-view-scroll-down-or-previous-page}).
496 @findex doc-view-first-page
497 @findex doc-view-last-page
498 @findex doc-view-goto-page
499 @kindex M-< @r{(DocView mode)}
500 @kindex M-> @r{(DocView mode)}
501 To go to the first page, type @kbd{M-<}
502 (@code{doc-view-first-page}); to go to the last one, type @kbd{M->}
503 (@code{doc-view-last-page}). To jump to a page by its number, type
504 @kbd{M-g M-g} or @kbd{M-g g} (@code{doc-view-goto-page}).
506 @findex doc-view-enlarge
507 @findex doc-view-shrink
508 @vindex doc-view-resolution
509 @kindex + @r{(DocView mode)}
510 @kindex - @r{(DocView mode)}
511 You can enlarge or shrink the document with @kbd{+}
512 (@code{doc-view-enlarge}) and @kbd{-} (@code{doc-view-shrink}). These
513 commands work by reconverting the document at the new size. To
514 specify the default size for DocView, customize the variable
515 @code{doc-view-resolution}.
517 @node DocView Searching
518 @subsection DocView Searching
520 In DocView mode, you can search the file's text for a regular
521 expression (@pxref{Regexps}). The interface for searching is inspired
522 by @code{isearch} (@pxref{Incremental Search}).
524 @findex doc-view-search
525 @findex doc-view-search-backward
526 @findex doc-view-show-tooltip
527 To begin a search, type @kbd{C-s} (@code{doc-view-search}) or
528 @kbd{C-r} (@code{doc-view-search-backward}). This reads a regular
529 expression using a minibuffer, then echoes the number of matches found
530 within the document. You can move forward and back among the matches
531 by typing @kbd{C-s} and @kbd{C-r}. DocView mode has no way to show
532 the match inside the page image; instead, it displays a tooltip (at
533 the mouse position) listing all matching lines in the current page.
534 To force display of this tooltip, type @kbd{C-t}
535 (@code{doc-view-show-tooltip}).
537 To start a new search, use the search command with a prefix
538 argument; i.e., @kbd{C-u C-s} for a forward search or @kbd{C-u C-r}
539 for a backward search.
541 @node DocView Slicing
542 @subsection DocView Slicing
544 Documents often have wide margins for printing. They are annoying
545 when reading the document on the screen, because they use up screen
546 space and can cause inconvenient scrolling.
548 @findex doc-view-set-slice
549 @findex doc-view-set-slice-using-mouse
550 With DocView you can hide these margins by selecting a @dfn{slice}
551 of pages to display. A slice is a rectangle within the page area;
552 once you specify a slice in DocView, it applies to whichever page you
555 To specify the slice numerically, type @kbd{s s}
556 (@code{doc-view-set-slice}); then enter the top left pixel position
557 and the slice's width and height.
558 @c ??? how does this work?
560 A more convenient graphical way to specify the slice is with @kbd{s
561 m} (@code{doc-view-set-slice-using-mouse}), where you use the mouse to
562 select the slice. Simply press and hold the left mouse button at the
563 upper-left corner of the region you want to have in the slice, then
564 move the mouse pointer to the lower-right corner and release the
567 The most convenient way is to set the optimal slice by using
568 BoundingBox information automatically determined from the document by
569 typing @kbd{s b} (@code{doc-view-set-slice-from-bounding-box}).
571 @findex doc-view-reset-slice
572 To cancel the selected slice, type @kbd{s r}
573 (@code{doc-view-reset-slice}). Then DocView shows the entire page
574 including its entire margins.
576 @node DocView Conversion
577 @subsection DocView Conversion
579 @vindex doc-view-cache-directory
580 @findex doc-view-clear-cache
581 For efficiency, DocView caches the images produced by @command{gs}.
582 The name of this directory is given by the variable
583 @code{doc-view-cache-directory}. You can clear the cache directory by
584 typing @code{M-x doc-view-clear-cache}.
586 @findex doc-view-kill-proc
587 @findex doc-view-kill-proc-and-buffer
588 To force reconversion of the currently viewed document, type @kbd{r}
589 or @kbd{g} (@code{revert-buffer}). To kill the converter process
590 associated with the current buffer, type @kbd{K}
591 (@code{doc-view-kill-proc}). The command @kbd{k}
592 (@code{doc-view-kill-proc-and-buffer}) kills the converter process and
596 @section Web Browsing with EWW
599 @findex eww-open-file
600 @dfn{EWW}, the Emacs Web Wowser, is a web browser package for Emacs.
601 It allows browsing URLs within an Emacs buffer. The command @kbd{M-x
602 eww} will open a URL or search the web. You can open a file
603 using the command @kbd{M-x eww-open-file}. You can use EWW as the
604 web browser for @code{browse-url}, @pxref{Browse-URL}. For full
605 details, @pxref{Top, EWW,, eww, The Emacs Web Wowser Manual}.
608 @section Running Shell Commands from Emacs
610 @cindex shell commands
612 Emacs has commands for passing single command lines to shell
613 subprocesses, and for running a shell interactively with input and
614 output to an Emacs buffer, and for running a shell in a terminal
618 @item M-! @var{cmd} @key{RET}
619 Run the shell command @var{cmd} and display the output
620 (@code{shell-command}).
621 @item M-| @var{cmd} @key{RET}
622 Run the shell command @var{cmd} with region contents as input;
623 optionally replace the region with the output
624 (@code{shell-command-on-region}).
625 @item M-& @var{cmd} @key{RET}
626 Run the shell command @var{cmd} asynchronously, and display the output
627 (@code{async-shell-command}).
629 Run a subshell with input and output through an Emacs buffer. You can
630 then give commands interactively.
632 Run a subshell with input and output through an Emacs buffer. You can
633 then give commands interactively. Full terminal emulation is
638 Whenever you specify a relative file name for an executable program
639 (either in the @var{cmd} argument to one of the above commands, or in
640 other contexts), Emacs searches for the program in the directories
641 specified by the variable @code{exec-path}. The value of this
642 variable must be a list of directory names; the default value is
643 initialized from the environment variable @env{PATH} when Emacs is
644 started (@pxref{General Variables}).
646 @kbd{M-x eshell} invokes a shell implemented entirely in Emacs. It
647 is documented in its own manual.
649 @xref{Top,Eshell,Eshell, eshell, Eshell: The Emacs Shell}.
652 See the Eshell Info manual, which is distributed with Emacs.
656 * Single Shell:: How to run one shell command and return.
657 * Interactive Shell:: Permanent shell taking input via Emacs.
658 * Shell Mode:: Special Emacs commands used with permanent shell.
659 * Shell Prompts:: Two ways to recognize shell prompts.
660 * History: Shell History. Repeating previous commands in a shell buffer.
661 * Directory Tracking:: Keeping track when the subshell changes directory.
662 * Options: Shell Options. Options for customizing Shell mode.
663 * Terminal emulator:: An Emacs window as a terminal emulator.
664 * Term Mode:: Special Emacs commands used in Term mode.
665 * Remote Host:: Connecting to another computer.
666 * Serial Terminal:: Connecting to a serial port.
670 @subsection Single Shell Commands
673 @findex shell-command
674 @kbd{M-!} (@code{shell-command}) reads a line of text using the
675 minibuffer and executes it as a shell command, in a subshell made just
676 for that command. Standard input for the command comes from the null
677 device. If the shell command produces any output, the output appears
678 either in the echo area (if it is short), or in an Emacs buffer named
679 @file{*Shell Command Output*}, displayed in another window (if the
682 For instance, one way to decompress a file named @file{foo.gz} is to
683 type @kbd{M-! gunzip foo.gz @key{RET}}. That shell command normally
684 creates the file @file{foo} and produces no terminal output.
686 A numeric argument to @code{shell-command}, e.g., @kbd{M-1 M-!},
687 causes it to insert terminal output into the current buffer instead of
688 a separate buffer. It puts point before the output, and sets the mark
689 after the output. For instance, @kbd{M-1 M-! gunzip < foo.gz
690 @key{RET}} would insert the uncompressed form of the file
691 @file{foo.gz} into the current buffer.
693 Provided the specified shell command does not end with @samp{&}, it
694 runs @dfn{synchronously}, and you must wait for it to exit before
695 continuing to use Emacs. To stop waiting, type @kbd{C-g} to quit;
696 this sends a @code{SIGINT} signal to terminate the shell command (this
697 is the same signal that @kbd{C-c} normally generates in the shell).
698 Emacs then waits until the command actually terminates. If the shell
699 command doesn't stop (because it ignores the @code{SIGINT} signal),
700 type @kbd{C-g} again; this sends the command a @code{SIGKILL} signal,
701 which is impossible to ignore.
704 @findex async-shell-command
705 A shell command that ends in @samp{&} is executed
706 @dfn{asynchronously}, and you can continue to use Emacs as it runs.
707 You can also type @kbd{M-&} (@code{async-shell-command}) to execute a
708 shell command asynchronously; this is exactly like calling @kbd{M-!}
709 with a trailing @samp{&}, except that you do not need the @samp{&}.
710 The default output buffer for asynchronous shell commands is named
711 @samp{*Async Shell Command*}. Emacs inserts the output into this
712 buffer as it comes in, whether or not the buffer is visible in a
715 @vindex async-shell-command-buffer
716 If you want to run more than one asynchronous shell command at the
717 same time, they could end up competing for the output buffer. The
718 option @code{async-shell-command-buffer} specifies what to do about
719 this; e.g., whether to rename the pre-existing output buffer, or to
720 use a different buffer for the new command. Consult the variable's
721 documentation for more possibilities.
724 @findex shell-command-on-region
725 @kbd{M-|} (@code{shell-command-on-region}) is like @kbd{M-!}, but
726 passes the contents of the region as the standard input to the shell
727 command, instead of no input. With a numeric argument, it deletes the
728 old region and replaces it with the output from the shell command.
730 For example, you can use @kbd{M-|} with the @command{gpg} program to
731 see what keys are in the buffer. If the buffer contains a GnuPG key,
732 type @kbd{C-x h M-| gpg @key{RET}} to feed the entire buffer contents
733 to @command{gpg}. This will output the list of keys to the
734 @file{*Shell Command Output*} buffer.
736 @vindex shell-file-name
737 The above commands use the shell specified by the variable
738 @code{shell-file-name}. Its default value is determined by the
739 @env{SHELL} environment variable when Emacs is started. If the file
740 name is relative, Emacs searches the directories listed in
741 @code{exec-path} (@pxref{Shell}).
743 To specify a coding system for @kbd{M-!} or @kbd{M-|}, use the command
744 @kbd{C-x @key{RET} c} immediately beforehand. @xref{Communication Coding}.
746 @vindex shell-command-default-error-buffer
747 By default, error output is intermixed with the regular output in
748 the output buffer. But if you change the value of the variable
749 @code{shell-command-default-error-buffer} to a string, error output is
750 inserted into a buffer of that name.
752 @node Interactive Shell
753 @subsection Interactive Subshell
756 To run a subshell interactively, type @kbd{M-x shell}. This creates
757 (or reuses) a buffer named @file{*shell*}, and runs a shell subprocess
758 with input coming from and output going to that buffer. That is to
759 say, any terminal output from the subshell goes into the buffer,
760 advancing point, and any terminal input for the subshell comes from
761 text in the buffer. To give input to the subshell, go to the end of
762 the buffer and type the input, terminated by @key{RET}.
764 While the subshell is waiting or running a command, you can switch
765 windows or buffers and perform other editing in Emacs. Emacs inserts
766 the output from the subshell into the Shell buffer whenever it has
767 time to process it (e.g., while waiting for keyboard input).
769 @cindex @code{comint-highlight-input} face
770 @cindex @code{comint-highlight-prompt} face
771 In the Shell buffer, prompts are displayed with the face
772 @code{comint-highlight-prompt}, and submitted input lines are
773 displayed with the face @code{comint-highlight-input}. This makes it
774 easier to distinguish input lines from the shell output.
777 To make multiple subshells, invoke @kbd{M-x shell} with a prefix
778 argument (e.g., @kbd{C-u M-x shell}). Then the command will read a
779 buffer name, and create (or reuse) a subshell in that buffer. You can
780 also rename the @file{*shell*} buffer using @kbd{M-x rename-uniquely},
781 then create a new @file{*shell*} buffer using plain @kbd{M-x shell}.
782 Subshells in different buffers run independently and in parallel.
784 @vindex explicit-shell-file-name
785 @cindex environment variables for subshells
786 @cindex @env{ESHELL} environment variable
787 @cindex @env{SHELL} environment variable
788 To specify the shell file name used by @kbd{M-x shell}, customize
789 the variable @code{explicit-shell-file-name}. If this is @code{nil}
790 (the default), Emacs uses the environment variable @env{ESHELL} if it
791 exists. Otherwise, it usually uses the variable
792 @code{shell-file-name} (@pxref{Single Shell}); but if the default
793 directory is remote (@pxref{Remote Files}), it prompts you for the
796 Emacs sends the new shell the contents of the file
797 @file{~/.emacs_@var{shellname}} as input, if it exists, where
798 @var{shellname} is the name of the file that the shell was loaded
799 from. For example, if you use bash, the file sent to it is
800 @file{~/.emacs_bash}. If this file is not found, Emacs tries with
801 @file{~/.emacs.d/init_@var{shellname}.sh}.
803 To specify a coding system for the shell, you can use the command
804 @kbd{C-x @key{RET} c} immediately before @kbd{M-x shell}. You can
805 also change the coding system for a running subshell by typing
806 @kbd{C-x @key{RET} p} in the shell buffer. @xref{Communication
809 @cindex @env{INSIDE_EMACS} environment variable
810 Emacs sets the environment variable @env{INSIDE_EMACS} in the
811 subshell to @samp{@var{version},comint}, where @var{version} is the
812 Emacs version (e.g., @samp{24.1}). Programs can check this variable
813 to determine whether they are running inside an Emacs subshell.
816 @subsection Shell Mode
820 The major mode for Shell buffers is Shell mode. Many of its special
821 commands are bound to the @kbd{C-c} prefix, and resemble the usual
822 editing and job control characters present in ordinary shells, except
823 that you must type @kbd{C-c} first. Here is a list of Shell mode
828 @kindex RET @r{(Shell mode)}
829 @findex comint-send-input
830 Send the current line as input to the subshell
831 (@code{comint-send-input}). Any shell prompt at the beginning of the
832 line is omitted (@pxref{Shell Prompts}). If point is at the end of
833 buffer, this is like submitting the command line in an ordinary
834 interactive shell. However, you can also invoke @key{RET} elsewhere
835 in the shell buffer to submit the current line as input.
838 @kindex TAB @r{(Shell mode)}
839 @findex completion-at-point
840 @cindex shell completion
841 Complete the command name or file name before point in the shell
842 buffer (@code{completion-at-point}). This uses the usual Emacs
843 completion rules (@pxref{Completion}), with the completion
844 alternatives being file names, environment variable names, the shell
845 command history, and history references (@pxref{History References}).
846 For options controlling the completion, @pxref{Shell Options}.
849 @kindex M-? @r{(Shell mode)}
850 @findex comint-dynamic-list-filename@dots{}
851 Display temporarily a list of the possible completions of the file
852 name before point (@code{comint-dynamic-list-filename-completions}).
855 @kindex C-d @r{(Shell mode)}
856 @findex comint-delchar-or-maybe-eof
857 Either delete a character or send @acronym{EOF}
858 (@code{comint-delchar-or-maybe-eof}). Typed at the end of the shell
859 buffer, this sends @acronym{EOF} to the subshell. Typed at any other
860 position in the buffer, this deletes a character as usual.
863 @kindex C-c C-a @r{(Shell mode)}
864 @findex comint-bol-or-process-mark
865 Move to the beginning of the line, but after the prompt if any
866 (@code{comint-bol-or-process-mark}). If you repeat this command twice
867 in a row, the second time it moves back to the process mark, which is
868 the beginning of the input that you have not yet sent to the subshell.
869 (Normally that is the same place---the end of the prompt on this
870 line---but after @kbd{C-c @key{SPC}} the process mark may be in a
874 Accumulate multiple lines of input, then send them together. This
875 command inserts a newline before point, but does not send the preceding
876 text as input to the subshell---at least, not yet. Both lines, the one
877 before this newline and the one after, will be sent together (along with
878 the newline that separates them), when you type @key{RET}.
881 @kindex C-c C-u @r{(Shell mode)}
882 @findex comint-kill-input
883 Kill all text pending at end of buffer to be sent as input
884 (@code{comint-kill-input}). If point is not at end of buffer,
885 this only kills the part of this text that precedes point.
888 @kindex C-c C-w @r{(Shell mode)}
889 Kill a word before point (@code{backward-kill-word}).
892 @kindex C-c C-c @r{(Shell mode)}
893 @findex comint-interrupt-subjob
894 Interrupt the shell or its current subjob if any
895 (@code{comint-interrupt-subjob}). This command also kills
896 any shell input pending in the shell buffer and not yet sent.
899 @kindex C-c C-z @r{(Shell mode)}
900 @findex comint-stop-subjob
901 Stop the shell or its current subjob if any (@code{comint-stop-subjob}).
902 This command also kills any shell input pending in the shell buffer and
906 @findex comint-quit-subjob
907 @kindex C-c C-\ @r{(Shell mode)}
908 Send quit signal to the shell or its current subjob if any
909 (@code{comint-quit-subjob}). This command also kills any shell input
910 pending in the shell buffer and not yet sent.
913 @kindex C-c C-o @r{(Shell mode)}
914 @findex comint-delete-output
915 Delete the last batch of output from a shell command
916 (@code{comint-delete-output}). This is useful if a shell command spews
917 out lots of output that just gets in the way.
920 @kindex C-c C-s @r{(Shell mode)}
921 @findex comint-write-output
922 Write the last batch of output from a shell command to a file
923 (@code{comint-write-output}). With a prefix argument, the file is
924 appended to instead. Any prompt at the end of the output is not
929 @kindex C-c C-r @r{(Shell mode)}
930 @kindex C-M-l @r{(Shell mode)}
931 @findex comint-show-output
932 Scroll to display the beginning of the last batch of output at the top
933 of the window; also move the cursor there (@code{comint-show-output}).
936 @kindex C-c C-e @r{(Shell mode)}
937 @findex comint-show-maximum-output
938 Scroll to put the end of the buffer at the bottom of the window
939 (@code{comint-show-maximum-output}).
942 @kindex C-c C-f @r{(Shell mode)}
943 @findex shell-forward-command
944 @vindex shell-command-regexp
945 Move forward across one shell command, but not beyond the current line
946 (@code{shell-forward-command}). The variable @code{shell-command-regexp}
947 specifies how to recognize the end of a command.
950 @kindex C-c C-b @r{(Shell mode)}
951 @findex shell-backward-command
952 Move backward across one shell command, but not beyond the current line
953 (@code{shell-backward-command}).
956 Ask the shell for its working directory, and update the Shell buffer's
957 default directory. @xref{Directory Tracking}.
959 @item M-x send-invisible @key{RET} @var{text} @key{RET}
960 @findex send-invisible
961 Send @var{text} as input to the shell, after reading it without
962 echoing. This is useful when a shell command runs a program that asks
965 Please note that Emacs will not echo passwords by default. If you
966 really want them to be echoed, evaluate (@pxref{Lisp Eval}) the
967 following Lisp expression:
970 (remove-hook 'comint-output-filter-functions
971 'comint-watch-for-password-prompt)
974 @item M-x comint-continue-subjob
975 @findex comint-continue-subjob
976 Continue the shell process. This is useful if you accidentally suspend
977 the shell process.@footnote{You should not suspend the shell process.
978 Suspending a subjob of the shell is a completely different matter---that
979 is normal practice, but you must use the shell to continue the subjob;
980 this command won't do it.}
982 @item M-x comint-strip-ctrl-m
983 @findex comint-strip-ctrl-m
984 Discard all control-M characters from the current group of shell output.
985 The most convenient way to use this command is to make it run
986 automatically when you get output from the subshell. To do that,
987 evaluate this Lisp expression:
990 (add-hook 'comint-output-filter-functions
991 'comint-strip-ctrl-m)
994 @item M-x comint-truncate-buffer
995 @findex comint-truncate-buffer
996 This command truncates the shell buffer to a certain maximum number of
997 lines, specified by the variable @code{comint-buffer-maximum-size}.
998 Here's how to do this automatically each time you get output from the
1002 (add-hook 'comint-output-filter-functions
1003 'comint-truncate-buffer)
1008 @cindex mode, Comint
1009 Shell mode is a derivative of Comint mode, a general-purpose mode for
1010 communicating with interactive subprocesses. Most of the features of
1011 Shell mode actually come from Comint mode, as you can see from the
1012 command names listed above. The special features of Shell mode include
1013 the directory tracking feature, and a few user commands.
1015 Other Emacs features that use variants of Comint mode include GUD
1016 (@pxref{Debuggers}) and @kbd{M-x run-lisp} (@pxref{External Lisp}).
1019 You can use @kbd{M-x comint-run} to execute any program of your choice
1020 in a subprocess using unmodified Comint mode---without the
1021 specializations of Shell mode.
1024 @subsection Shell Prompts
1026 @cindex prompt, shell
1027 A prompt is text output by a program to show that it is ready to
1028 accept new user input. Normally, Comint mode (and thus Shell mode)
1029 automatically figures out part of the buffer is a prompt, based on the
1030 output of the subprocess. (Specifically, it assumes that any received
1031 output line which doesn't end with a newline is a prompt.)
1033 Comint mode divides the buffer into two types of @dfn{fields}: input
1034 fields (where user input is typed) and output fields (everywhere
1035 else). Prompts are part of the output fields. Most Emacs motion
1036 commands do not cross field boundaries, unless they move over multiple
1037 lines. For instance, when point is in the input field on a shell
1038 command line, @kbd{C-a} puts point at the beginning of the input
1039 field, after the prompt. Internally, the fields are implemented using
1040 the @code{field} text property (@pxref{Text Properties,,, elisp, the
1041 Emacs Lisp Reference Manual}).
1043 @vindex comint-use-prompt-regexp
1044 @vindex shell-prompt-pattern
1045 If you change the variable @code{comint-use-prompt-regexp} to a
1046 non-@code{nil} value, then Comint mode recognize prompts using a
1047 regular expression (@pxref{Regexps}). In Shell mode, the regular
1048 expression is specified by the variable @code{shell-prompt-pattern}.
1049 The default value of @code{comint-use-prompt-regexp} is @code{nil},
1050 because this method for recognizing prompts is unreliable, but you may
1051 want to set it to a non-@code{nil} value in unusual circumstances. In
1052 that case, Emacs does not divide the Comint buffer into fields, so the
1053 general motion commands behave as they normally do in buffers without
1054 special text properties. However, you can use the paragraph motion
1055 commands to conveniently navigate the buffer (@pxref{Paragraphs}); in
1056 Shell mode, Emacs uses @code{shell-prompt-pattern} as paragraph
1060 @subsection Shell Command History
1062 Shell buffers support three ways of repeating earlier commands. You
1063 can use keys like those used for the minibuffer history; these work
1064 much as they do in the minibuffer, inserting text from prior commands
1065 while point remains always at the end of the buffer. You can move
1066 through the buffer to previous inputs in their original place, then
1067 resubmit them or copy them to the end. Or you can use a
1068 @samp{!}-style history reference.
1071 * Ring: Shell Ring. Fetching commands from the history list.
1072 * Copy: Shell History Copying. Moving to a command and then copying it.
1073 * History References:: Expanding @samp{!}-style history references.
1077 @subsubsection Shell History Ring
1080 @findex comint-previous-input
1081 @kindex M-p @r{(Shell mode)}
1084 Fetch the next earlier old shell command.
1086 @kindex M-n @r{(Shell mode)}
1087 @findex comint-next-input
1090 Fetch the next later old shell command.
1092 @kindex M-r @r{(Shell mode)}
1093 @findex comint-history-isearch-backward-regexp
1095 Begin an incremental regexp search of old shell commands.
1098 @kindex C-c C-x @r{(Shell mode)}
1099 @findex comint-get-next-from-history
1100 Fetch the next subsequent command from the history.
1103 @kindex C-c . @r{(Shell mode)}
1104 @findex comint-input-previous-argument
1105 Fetch one argument from an old shell command.
1108 @kindex C-c C-l @r{(Shell mode)}
1109 @findex comint-dynamic-list-input-ring
1110 Display the buffer's history of shell commands in another window
1111 (@code{comint-dynamic-list-input-ring}).
1114 Shell buffers provide a history of previously entered shell
1115 commands. To reuse shell commands from the history, use the editing
1116 commands @kbd{M-p}, @kbd{M-n}, @kbd{M-r} and @kbd{M-s}. These work
1117 just like the minibuffer history commands (@pxref{Minibuffer
1118 History}), except that they operate within the Shell buffer rather
1119 than the minibuffer.
1121 @kbd{M-p} fetches an earlier shell command to the end of the shell
1122 buffer. Successive use of @kbd{M-p} fetches successively earlier
1123 shell commands, each replacing any text that was already present as
1124 potential shell input. @kbd{M-n} does likewise except that it finds
1125 successively more recent shell commands from the buffer.
1126 @kbd{C-@key{UP}} works like @kbd{M-p}, and @kbd{C-@key{DOWN}} like
1129 The history search command @kbd{M-r} begins an incremental regular
1130 expression search of previous shell commands. After typing @kbd{M-r},
1131 start typing the desired string or regular expression; the last
1132 matching shell command will be displayed in the current line.
1133 Incremental search commands have their usual effects---for instance,
1134 @kbd{C-s} and @kbd{C-r} search forward and backward for the next match
1135 (@pxref{Incremental Search}). When you find the desired input, type
1136 @key{RET} to terminate the search. This puts the input in the command
1137 line. Any partial input you were composing before navigating the
1138 history list is restored when you go to the beginning or end of the
1141 Often it is useful to reexecute several successive shell commands that
1142 were previously executed in sequence. To do this, first find and
1143 reexecute the first command of the sequence. Then type @kbd{C-c C-x};
1144 that will fetch the following command---the one that follows the command
1145 you just repeated. Then type @key{RET} to reexecute this command. You
1146 can reexecute several successive commands by typing @kbd{C-c C-x
1147 @key{RET}} over and over.
1149 The command @kbd{C-c .}@: (@code{comint-input-previous-argument})
1150 copies an individual argument from a previous command, like
1151 @kbd{@key{ESC} .} in Bash. The simplest use copies the last argument from the
1152 previous shell command. With a prefix argument @var{n}, it copies the
1153 @var{n}th argument instead. Repeating @kbd{C-c .} copies from an
1154 earlier shell command instead, always using the same value of @var{n}
1155 (don't give a prefix argument when you repeat the @kbd{C-c .}
1158 These commands get the text of previous shell commands from a special
1159 history list, not from the shell buffer itself. Thus, editing the shell
1160 buffer, or even killing large parts of it, does not affect the history
1161 that these commands access.
1163 @vindex shell-input-ring-file-name
1164 Some shells store their command histories in files so that you can
1165 refer to commands from previous shell sessions. Emacs reads
1166 the command history file for your chosen shell, to initialize its own
1167 command history. The file name is @file{~/.bash_history} for bash,
1168 @file{~/.sh_history} for ksh, and @file{~/.history} for other shells.
1170 @node Shell History Copying
1171 @subsubsection Shell History Copying
1174 @kindex C-c C-p @r{(Shell mode)}
1175 @findex comint-previous-prompt
1177 Move point to the previous prompt (@code{comint-previous-prompt}).
1179 @kindex C-c C-n @r{(Shell mode)}
1180 @findex comint-next-prompt
1182 Move point to the following prompt (@code{comint-next-prompt}).
1184 @kindex C-c RET @r{(Shell mode)}
1185 @findex comint-copy-old-input
1187 Copy the input command at point, inserting the copy at the end of the
1188 buffer (@code{comint-copy-old-input}). This is useful if you move
1189 point back to a previous command. After you copy the command, you can
1190 submit the copy as input with @key{RET}. If you wish, you can edit
1191 the copy before resubmitting it. If you use this command on an output
1192 line, it copies that line to the end of the buffer.
1195 If @code{comint-use-prompt-regexp} is @code{nil} (the default), copy
1196 the old input command that you click on, inserting the copy at the end
1197 of the buffer (@code{comint-insert-input}). If
1198 @code{comint-use-prompt-regexp} is non-@code{nil}, or if the click is
1199 not over old input, just yank as usual.
1202 Moving to a previous input and then copying it with @kbd{C-c
1203 @key{RET}} or @kbd{Mouse-2} produces the same results---the same
1204 buffer contents---that you would get by using @kbd{M-p} enough times
1205 to fetch that previous input from the history list. However, @kbd{C-c
1206 @key{RET}} copies the text from the buffer, which can be different
1207 from what is in the history list if you edit the input text in the
1208 buffer after it has been sent.
1210 @node History References
1211 @subsubsection Shell History References
1212 @cindex history reference
1214 Various shells including csh and bash support @dfn{history
1215 references} that begin with @samp{!} and @samp{^}. Shell mode
1216 recognizes these constructs, and can perform the history substitution
1219 If you insert a history reference and type @key{TAB}, this searches
1220 the input history for a matching command, performs substitution if
1221 necessary, and places the result in the buffer in place of the history
1222 reference. For example, you can fetch the most recent command
1223 beginning with @samp{mv} with @kbd{! m v @key{TAB}}. You can edit the
1224 command if you wish, and then resubmit the command to the shell by
1227 @vindex comint-input-autoexpand
1228 @findex comint-magic-space
1229 Shell mode can optionally expand history references in the buffer
1230 when you send them to the shell. To request this, set the variable
1231 @code{comint-input-autoexpand} to @code{input}. You can make
1232 @key{SPC} perform history expansion by binding @key{SPC} to the
1233 command @code{comint-magic-space}.
1235 Shell mode recognizes history references when they follow a prompt.
1236 @xref{Shell Prompts}, for how Shell mode recognizes prompts.
1238 @node Directory Tracking
1239 @subsection Directory Tracking
1240 @cindex directory tracking
1242 @vindex shell-pushd-regexp
1243 @vindex shell-popd-regexp
1244 @vindex shell-cd-regexp
1245 Shell mode keeps track of @samp{cd}, @samp{pushd} and @samp{popd}
1246 commands given to the subshell, in order to keep the Shell buffer's
1247 default directory (@pxref{File Names}) the same as the shell's working
1248 directory. It recognizes these commands by examining lines of input
1251 If you use aliases for these commands, you can tell Emacs to
1252 recognize them also, by setting the variables
1253 @code{shell-pushd-regexp}, @code{shell-popd-regexp}, and
1254 @code{shell-cd-regexp} to the appropriate regular expressions
1255 (@pxref{Regexps}). For example, if @code{shell-pushd-regexp} matches
1256 the beginning of a shell command line, that line is regarded as a
1257 @code{pushd} command. These commands are recognized only at the
1258 beginning of a shell command line.
1261 If Emacs gets confused about changes in the working directory of the
1262 subshell, type @kbd{M-x dirs}. This command asks the shell for its
1263 working directory and updates the default directory accordingly. It
1264 works for shells that support the most common command syntax, but may
1265 not work for unusual shells.
1267 @findex dirtrack-mode
1268 @cindex Dirtrack mode
1269 @cindex mode, Dirtrack
1270 @vindex dirtrack-list
1271 You can also use Dirtrack mode, a buffer-local minor mode that
1272 implements an alternative method of tracking the shell's working
1273 directory. To use this method, your shell prompt must contain the
1274 working directory at all times, and you must supply a regular
1275 expression for recognizing which part of the prompt contains the
1276 working directory; see the documentation of the variable
1277 @code{dirtrack-list} for details. To use Dirtrack mode, type @kbd{M-x
1278 dirtrack-mode} in the Shell buffer, or add @code{dirtrack-mode} to
1279 @code{shell-mode-hook} (@pxref{Hooks}).
1282 @subsection Shell Mode Options
1284 @vindex comint-scroll-to-bottom-on-input
1285 If the variable @code{comint-scroll-to-bottom-on-input} is
1286 non-@code{nil}, insertion and yank commands scroll the selected window
1287 to the bottom before inserting. The default is @code{nil}.
1289 @vindex comint-scroll-show-maximum-output
1290 If @code{comint-scroll-show-maximum-output} is non-@code{nil}, then
1291 arrival of output when point is at the end tries to scroll the last
1292 line of text to the bottom line of the window, showing as much useful
1293 text as possible. (This mimics the scrolling behavior of most
1294 terminals.) The default is @code{t}.
1296 @vindex comint-move-point-for-output
1297 By setting @code{comint-move-point-for-output}, you can opt for
1298 having point jump to the end of the buffer whenever output arrives---no
1299 matter where in the buffer point was before. If the value is
1300 @code{this}, point jumps in the selected window. If the value is
1301 @code{all}, point jumps in each window that shows the Comint buffer. If
1302 the value is @code{other}, point jumps in all nonselected windows that
1303 show the current buffer. The default value is @code{nil}, which means
1304 point does not jump to the end.
1306 @vindex comint-prompt-read-only
1307 If you set @code{comint-prompt-read-only}, the prompts in the Comint
1308 buffer are read-only.
1310 @vindex comint-input-ignoredups
1311 The variable @code{comint-input-ignoredups} controls whether successive
1312 identical inputs are stored in the input history. A non-@code{nil}
1313 value means to omit an input that is the same as the previous input.
1314 The default is @code{nil}, which means to store each input even if it is
1315 equal to the previous input.
1317 @vindex comint-completion-addsuffix
1318 @vindex comint-completion-recexact
1319 @vindex comint-completion-autolist
1320 Three variables customize file name completion. The variable
1321 @code{comint-completion-addsuffix} controls whether completion inserts a
1322 space or a slash to indicate a fully completed file or directory name
1323 (non-@code{nil} means do insert a space or slash).
1324 @code{comint-completion-recexact}, if non-@code{nil}, directs @key{TAB}
1325 to choose the shortest possible completion if the usual Emacs completion
1326 algorithm cannot add even a single character.
1327 @code{comint-completion-autolist}, if non-@code{nil}, says to list all
1328 the possible completions whenever completion is not exact.
1330 @vindex shell-completion-execonly
1331 Command completion normally considers only executable files.
1332 If you set @code{shell-completion-execonly} to @code{nil},
1333 it considers nonexecutable files as well.
1335 @vindex shell-completion-fignore
1336 @vindex comint-completion-fignore
1337 The variable @code{shell-completion-fignore} specifies a list of file
1338 name extensions to ignore in Shell mode completion. The default
1339 setting is @code{nil}, but some users prefer @code{("~" "#" "%")} to
1340 ignore file names ending in @samp{~}, @samp{#} or @samp{%}. Other
1341 related Comint modes use the variable @code{comint-completion-fignore}
1344 @findex shell-dynamic-complete-command
1345 Some implementation details of the shell command completion may also be found
1346 in the lisp documentation of the @code{shell-dynamic-complete-command}
1349 @findex shell-pushd-tohome
1350 @findex shell-pushd-dextract
1351 @findex shell-pushd-dunique
1352 You can configure the behavior of @samp{pushd}. Variables control
1353 whether @samp{pushd} behaves like @samp{cd} if no argument is given
1354 (@code{shell-pushd-tohome}), pop rather than rotate with a numeric
1355 argument (@code{shell-pushd-dextract}), and only add directories to the
1356 directory stack if they are not already on it
1357 (@code{shell-pushd-dunique}). The values you choose should match the
1358 underlying shell, of course.
1360 @node Terminal emulator
1361 @subsection Emacs Terminal Emulator
1364 To run a subshell in a text terminal emulator, use @kbd{M-x term}.
1365 This creates (or reuses) a buffer named @file{*terminal*}, and runs a
1366 subshell with input coming from your keyboard, and output going to
1369 @cindex line mode @r{(terminal emulator)}
1370 @cindex char mode @r{(terminal emulator)}
1371 The terminal emulator uses Term mode, which has two input modes. In
1372 @dfn{line mode}, Term basically acts like Shell mode (@pxref{Shell
1373 Mode}). In @dfn{char mode}, each character is sent directly to the
1374 subshell, as terminal input; the sole exception is the terminal escape
1375 character, which by default is @kbd{C-c} (@pxref{Term Mode}). Any
1376 echoing of your input is the responsibility of the subshell; any
1377 terminal output from the subshell goes into the buffer, advancing
1380 Some programs (such as Emacs itself) need to control the appearance
1381 of the terminal screen in detail. They do this by emitting special
1382 control codes. Term mode recognizes and handles ANSI-standard
1383 VT100-style escape sequences, which are accepted by most modern
1384 terminals, including @command{xterm}. (Hence, you can actually run
1385 Emacs inside an Emacs Term window.)
1387 The @code{term} face specifies the default appearance of text
1388 in the terminal emulator (the default is the same appearance as the
1389 @code{default} face). When terminal control codes are used to change
1390 the appearance of text, these are represented in the terminal emulator
1391 by the faces @code{term-color-black}, @code{term-color-red},
1392 @code{term-color-green}, @code{term-color-yellow}
1393 @code{term-color-blue}, @code{term-color-magenta},
1394 @code{term-color-cyan}, @code{term-color-white},
1395 @code{term-color-underline}, and @code{term-color-bold}.
1398 You can also Term mode to communicate with a device connected to a
1399 serial port. @xref{Serial Terminal}.
1401 The file name used to load the subshell is determined the same way
1402 as for Shell mode. To make multiple terminal emulators, rename the
1403 buffer @file{*terminal*} to something different using @kbd{M-x
1404 rename-uniquely}, just as with Shell mode.
1406 Unlike Shell mode, Term mode does not track the current directory by
1407 examining your input. But some shells can tell Term what the current
1408 directory is. This is done automatically by @code{bash} version 1.15
1415 @subsection Term Mode
1419 The terminal emulator uses Term mode, which has two input modes. In
1420 line mode, Term basically acts like Shell mode (@pxref{Shell Mode}).
1421 In char mode, each character is sent directly to the subshell, except
1422 for the Term escape character, normally @kbd{C-c}.
1424 To switch between line and char mode, use these commands:
1427 @kindex C-c C-j @r{(Term mode)}
1428 @findex term-line-mode
1430 Switch to line mode (@code{term-line-mode}). Do nothing if already in
1433 @kindex C-c C-k @r{(Term mode)}
1434 @findex term-char-mode
1436 Switch to char mode (@code{term-char-mode}). Do nothing if already in
1440 The following commands are only available in char mode:
1444 Send a literal @kbd{C-c} to the sub-shell.
1446 @item C-c @var{char}
1447 This is equivalent to @kbd{C-x @var{char}} in normal Emacs. For
1448 example, @kbd{C-c o} invokes the global binding of @kbd{C-x o}, which
1449 is normally @samp{other-window}.
1452 @cindex paging in Term mode
1453 Term mode has a page-at-a-time feature. When enabled, it makes
1454 output pause at the end of each screenful:
1457 @kindex C-c C-q @r{(Term mode)}
1458 @findex term-pager-toggle
1460 Toggle the page-at-a-time feature. This command works in both line
1461 and char modes. When the feature is enabled, the mode-line displays
1462 the word @samp{page}, and each time Term receives more than a
1463 screenful of output, it pauses and displays @samp{**MORE**} in the
1464 mode-line. Type @key{SPC} to display the next screenful of output, or
1465 @kbd{?} to see your other options. The interface is similar to the
1466 @code{more} program.
1470 @subsection Remote Host Shell
1472 @cindex connecting to remote host
1476 You can login to a remote computer, using whatever commands you
1477 would from a regular terminal (e.g., using the @code{telnet} or
1478 @code{rlogin} commands), from a Term window.
1480 A program that asks you for a password will normally suppress
1481 echoing of the password, so the password will not show up in the
1482 buffer. This will happen just as if you were using a real terminal,
1483 if the buffer is in char mode. If it is in line mode, the password is
1484 temporarily visible, but will be erased when you hit return. (This
1485 happens automatically; there is no special password processing.)
1487 When you log in to a different machine, you need to specify the type
1488 of terminal you're using, by setting the @env{TERM} environment
1489 variable in the environment for the remote login command. (If you use
1490 bash, you do that by writing the variable assignment before the remote
1491 login command, without a separating comma.) Terminal types
1492 @samp{ansi} or @samp{vt100} will work on most systems.
1494 @node Serial Terminal
1495 @subsection Serial Terminal
1496 @cindex terminal, serial
1499 If you have a device connected to a serial port of your computer,
1500 you can communicate with it by typing @kbd{M-x serial-term}. This
1501 command asks for a serial port name and speed, and switches to a new
1502 Term mode buffer. Emacs communicates with the serial device through
1503 this buffer just like it does with a terminal in ordinary Term mode.
1505 The speed of the serial port is measured in bits per second. The
1506 most common speed is 9600 bits per second. You can change the speed
1507 interactively by clicking on the mode line.
1509 A serial port can be configured even more by clicking on @samp{8N1} in
1510 the mode line. By default, a serial port is configured as @samp{8N1},
1511 which means that each byte consists of 8 data bits, No parity check
1514 If the speed or the configuration is wrong, you cannot communicate
1515 with your device and will probably only see garbage output in the
1519 @section Using Emacs as a Server
1521 @cindex Emacs as a server
1522 @cindex server, using Emacs as
1523 @cindex @env{EDITOR} environment variable
1525 Various programs can invoke your choice of editor to edit a
1526 particular piece of text. For instance, version control programs
1527 invoke an editor to enter version control logs (@pxref{Version
1528 Control}), and the Unix @command{mail} utility invokes an editor to
1529 enter a message to send. By convention, your choice of editor is
1530 specified by the environment variable @env{EDITOR}. If you set
1531 @env{EDITOR} to @samp{emacs}, Emacs would be invoked, but in an
1532 inconvenient way---by starting a new Emacs process. This is
1533 inconvenient because the new Emacs process doesn't share buffers, a
1534 command history, or other kinds of information with any existing Emacs
1537 You can solve this problem by setting up Emacs as an @dfn{edit
1538 server}, so that it ``listens'' for external edit requests and acts
1539 accordingly. There are two ways to start an Emacs server:
1542 @findex server-start
1544 Run the command @code{server-start} in an existing Emacs process:
1545 either type @kbd{M-x server-start}, or put the expression
1546 @code{(server-start)} in your init file (@pxref{Init File}). The
1547 existing Emacs process is the server; when you exit Emacs, the server
1548 dies with the Emacs process.
1550 @cindex daemon, Emacs
1552 Run Emacs as a @dfn{daemon}, using the @samp{--daemon} command-line
1553 option. @xref{Initial Options}. When Emacs is started this way, it
1554 calls @code{server-start} after initialization, and returns control to
1555 the calling terminal instead of opening an initial frame; it then
1556 waits in the background, listening for edit requests.
1559 @cindex @env{TEXEDIT} environment variable
1560 Either way, once an Emacs server is started, you can use a shell
1561 command called @command{emacsclient} to connect to the Emacs process
1562 and tell it to visit a file. You can then set the @env{EDITOR}
1563 environment variable to @samp{emacsclient}, so that external programs
1564 will use the existing Emacs process for editing.@footnote{Some
1565 programs use a different environment variable; for example, to make
1566 @TeX{} use @samp{emacsclient}, set the @env{TEXEDIT} environment
1567 variable to @samp{emacsclient +%d %s}.}
1570 You can run multiple Emacs servers on the same machine by giving
1571 each one a unique @dfn{server name}, using the variable
1572 @code{server-name}. For example, @kbd{M-x set-variable @key{RET}
1573 server-name @key{RET} foo @key{RET}} sets the server name to
1574 @samp{foo}. The @code{emacsclient} program can specify a server by
1575 name, using the @samp{-s} option (@pxref{emacsclient Options}).
1577 @findex server-eval-at
1578 If you have defined a server by a unique server name, it is possible
1579 to connect to the server from another Emacs instance and evaluate Lisp
1580 expressions on the server, using the @code{server-eval-at} function.
1581 For instance, @code{(server-eval-at "foo" '(+ 1 2))} evaluates the
1582 expression @code{(+ 1 2)} on the @samp{foo} server, and returns
1583 @code{3}. (If there is no server with that name, an error is
1584 signaled.) Currently, this feature is mainly useful for developers.
1587 * Invoking emacsclient:: Connecting to the Emacs server.
1588 * emacsclient Options:: Emacs client startup options.
1591 @node Invoking emacsclient
1592 @subsection Invoking @code{emacsclient}
1593 @cindex @code{emacsclient} invocation
1595 The simplest way to use the @command{emacsclient} program is to run
1596 the shell command @samp{emacsclient @var{file}}, where @var{file} is a
1597 file name. This connects to an Emacs server, and tells that Emacs
1598 process to visit @var{file} in one of its existing frames---either a
1599 graphical frame, or one in a text terminal (@pxref{Frames}). You
1600 can then select that frame to begin editing.
1602 If there is no Emacs server, the @command{emacsclient} program halts
1603 with an error message. If the Emacs process has no existing
1604 frame---which can happen if it was started as a daemon (@pxref{Emacs
1605 Server})---then Emacs opens a frame on the terminal in which you
1606 called @command{emacsclient}.
1608 You can also force @command{emacsclient} to open a new frame on a
1609 graphical display, or on a text terminal, using the @samp{-c} and
1610 @samp{-t} options. @xref{emacsclient Options}.
1612 If you are running on a single text terminal, you can switch between
1613 @command{emacsclient}'s shell and the Emacs server using one of two
1614 methods: (i) run the Emacs server and @command{emacsclient} on
1615 different virtual terminals, and switch to the Emacs server's virtual
1616 terminal after calling @command{emacsclient}; or (ii) call
1617 @command{emacsclient} from within the Emacs server itself, using Shell
1618 mode (@pxref{Interactive Shell}) or Term mode (@pxref{Term Mode});
1619 @code{emacsclient} blocks only the subshell under Emacs, and you can
1620 still use Emacs to edit the file.
1624 When you finish editing @var{file} in the Emacs server, type
1625 @kbd{C-x #} (@code{server-edit}) in its buffer. This saves the file
1626 and sends a message back to the @command{emacsclient} program, telling
1627 it to exit. Programs that use @env{EDITOR} usually wait for the
1628 editor---in this case @command{emacsclient}---to exit before doing
1631 You can also call @command{emacsclient} with multiple file name
1632 arguments: @samp{emacsclient @var{file1} @var{file2} ...} tells the
1633 Emacs server to visit @var{file1}, @var{file2}, and so forth. Emacs
1634 selects the buffer visiting @var{file1}, and buries the other buffers
1635 at the bottom of the buffer list (@pxref{Buffers}). The
1636 @command{emacsclient} program exits once all the specified files are
1637 finished (i.e., once you have typed @kbd{C-x #} in each server
1640 @vindex server-kill-new-buffers
1641 @vindex server-temp-file-regexp
1642 Finishing with a server buffer also kills the buffer, unless it
1643 already existed in the Emacs session before the server was asked to
1644 create it. However, if you set @code{server-kill-new-buffers} to
1645 @code{nil}, then a different criterion is used: finishing with a
1646 server buffer kills it if the file name matches the regular expression
1647 @code{server-temp-file-regexp}. This is set up to distinguish certain
1650 Each @kbd{C-x #} checks for other pending external requests to edit
1651 various files, and selects the next such file. You can switch to a
1652 server buffer manually if you wish; you don't have to arrive at it
1653 with @kbd{C-x #}. But @kbd{C-x #} is the way to tell
1654 @command{emacsclient} that you are finished.
1656 @vindex server-window
1657 If you set the value of the variable @code{server-window} to a
1658 window or a frame, @kbd{C-x #} always displays the next server buffer
1659 in that window or in that frame.
1661 @node emacsclient Options
1662 @subsection @code{emacsclient} Options
1663 @cindex @code{emacsclient} options
1665 You can pass some optional arguments to the @command{emacsclient}
1669 emacsclient -c +12 @var{file1} +4:3 @var{file2}
1673 The @samp{+@var{line}} or @samp{+@var{line}:@var{column}} arguments
1674 specify line numbers, or line and column numbers, for the next file
1675 argument. These behave like the command line arguments for Emacs
1676 itself. @xref{Action Arguments}.
1678 The other optional arguments recognized by @command{emacsclient} are
1682 @item -a @var{command}
1683 @itemx --alternate-editor=@var{command}
1684 Specify a command to run if @code{emacsclient} fails to contact Emacs.
1685 This is useful when running @code{emacsclient} in a script.
1687 As a special exception, if @var{command} is the empty string, then
1688 @code{emacsclient} starts Emacs in daemon mode (as @command{emacs
1689 --daemon}) and then tries connecting again.
1691 @cindex @env{ALTERNATE_EDITOR} environment variable
1692 The environment variable @env{ALTERNATE_EDITOR} has the same effect as
1693 the @samp{-a} option. If both are present, the latter takes
1696 @cindex client frame
1698 @itemx --create-frame
1699 Create a new graphical @dfn{client frame}, instead of using an
1700 existing Emacs frame. See below for the special behavior of @kbd{C-x
1701 C-c} in a client frame. If Emacs cannot create a new graphical frame
1702 (e.g., if it cannot connect to the X server), it tries to create a
1703 text terminal client frame, as though you had supplied the @samp{-t}
1706 On MS-Windows, a single Emacs session cannot display frames on both
1707 graphical and text terminals, nor on multiple text terminals. Thus,
1708 if the Emacs server is running on a text terminal, the @samp{-c}
1709 option, like the @samp{-t} option, creates a new frame in the server's
1710 current text terminal. @xref{Windows Startup}.
1712 If you omit a filename argument while supplying the @samp{-c} option,
1713 the new frame displays the @file{*scratch*} buffer by default. You
1714 can customize this behavior with the variable @code{initial-buffer-choice}
1715 (@pxref{Entering Emacs}).
1717 @item -F @var{alist}
1718 @itemx --frame-parameters=@var{alist}
1719 Set the parameters for a newly-created graphical frame
1720 (@pxref{Frame Parameters}).
1722 @item -d @var{display}
1723 @itemx --display=@var{display}
1724 Tell Emacs to open the given files on the X display @var{display}
1725 (assuming there is more than one X display available).
1729 Tell Emacs to evaluate some Emacs Lisp code, instead of visiting some
1730 files. When this option is given, the arguments to
1731 @command{emacsclient} are interpreted as a list of expressions to
1732 evaluate, @emph{not} as a list of files to visit.
1734 @item -f @var{server-file}
1735 @itemx --server-file=@var{server-file}
1736 @cindex @env{EMACS_SERVER_FILE} environment variable
1737 Specify a @dfn{server file} for connecting to an Emacs server via TCP.
1739 An Emacs server usually uses a
1740 local socket to listen for connections. Some operating systems,
1741 such as Microsoft Windows, do not support local sockets; in that case,
1742 the server communicates with @command{emacsclient} via TCP.
1744 @vindex server-auth-dir
1747 When you start a TCP Emacs server, Emacs creates a @dfn{server file}
1748 containing the TCP information to be used by @command{emacsclient} to
1749 connect to the server. The variable @code{server-auth-dir} specifies
1750 the directory containing the server file; by default, this is
1751 @file{~/.emacs.d/server/}. To tell @command{emacsclient} to connect
1752 to the server over TCP with a specific server file, use the @samp{-f}
1753 or @samp{--server-file} option, or set the @env{EMACS_SERVER_FILE}
1754 environment variable.
1758 Let @command{emacsclient} exit immediately, instead of waiting until
1759 all server buffers are finished. You can take as long as you like to
1760 edit the server buffers within Emacs, and they are @emph{not} killed
1761 when you type @kbd{C-x #} in them.
1763 @item --parent-id @var{id}
1764 Open an @command{emacsclient} frame as a client frame in the parent X
1765 window with id @var{id}, via the XEmbed protocol. Currently, this
1766 option is mainly useful for developers.
1770 Do not let @command{emacsclient} display messages about waiting for
1771 Emacs or connecting to remote server sockets.
1773 @item -s @var{server-name}
1774 @itemx --socket-name=@var{server-name}
1775 Connect to the Emacs server named @var{server-name}. The server name
1776 is given by the variable @code{server-name} on the Emacs server. If
1777 this option is omitted, @command{emacsclient} connects to the first
1778 server it finds. (This option is not supported on MS-Windows.)
1783 Create a new client frame on the current text terminal, instead of
1784 using an existing Emacs frame. This behaves just like the @samp{-c}
1785 option, described above, except that it creates a text terminal frame
1786 (@pxref{Non-Window Terminals}).
1788 On MS-Windows, @samp{-t} behaves just like @samp{-c} if the Emacs
1789 server is using the graphical display, but if the Emacs server is
1790 running on a text terminal, it creates a new frame in the current text
1794 The new graphical or text terminal frames created by the @samp{-c}
1795 or @samp{-t} options are considered @dfn{client frames}. Any new
1796 frame that you create from a client frame is also considered a client
1797 frame. If you type @kbd{C-x C-c} (@code{save-buffers-kill-terminal})
1798 in a client frame, that command does not kill the Emacs session as it
1799 normally does (@pxref{Exiting}). Instead, Emacs deletes the client
1800 frame; furthermore, if the client frame has an @command{emacsclient}
1801 waiting to regain control (i.e., if you did not supply the @samp{-n}
1802 option), Emacs deletes all other frames of the same client, and marks
1803 the client's server buffers as finished, as though you had typed
1804 @kbd{C-x #} in all of them. If it so happens that there are no
1805 remaining frames after the client frame(s) are deleted, the Emacs
1808 As an exception, when Emacs is started as a daemon, all frames are
1809 considered client frames, and @kbd{C-x C-c} never kills Emacs. To
1810 kill a daemon session, type @kbd{M-x kill-emacs}.
1812 Note that the @samp{-t} and @samp{-n} options are contradictory:
1813 @samp{-t} says to take control of the current text terminal to create
1814 a new client frame, while @samp{-n} says not to take control of the
1815 text terminal. If you supply both options, Emacs visits the specified
1816 files(s) in an existing frame rather than a new client frame, negating
1817 the effect of @samp{-t}.
1820 @section Printing Hard Copies
1824 Emacs provides commands for printing hardcopies of either an entire
1825 buffer or part of one. You can invoke the printing commands directly,
1826 as detailed below, or using the @samp{File} menu on the menu bar.
1828 @findex htmlfontify-buffer
1829 Aside from the commands described in this section, you can also
1830 print hardcopies from Dired (@pxref{Operating on Files}) and the diary
1831 (@pxref{Displaying the Diary}). You can also ``print'' an Emacs
1832 buffer to HTML with the command @kbd{M-x htmlfontify-buffer}, which
1833 converts the current buffer to a HTML file, replacing Emacs faces with
1834 CSS-based markup. Furthermore, Org mode allows you to print Org
1835 files to a variety of formats, such as PDF (@pxref{Org Mode}).
1838 @item M-x print-buffer
1839 Print hardcopy of current buffer with page headings containing the
1840 file name and page number.
1841 @item M-x lpr-buffer
1842 Print hardcopy of current buffer without page headings.
1843 @item M-x print-region
1844 Like @code{print-buffer} but print only the current region.
1845 @item M-x lpr-region
1846 Like @code{lpr-buffer} but print only the current region.
1849 @findex print-buffer
1850 @findex print-region
1853 @vindex lpr-switches
1854 @vindex lpr-commands
1855 On most operating system, the above hardcopy commands submit files
1856 for printing by calling the @command{lpr} program. To change the
1857 printer program, customize the variable @code{lpr-command}. To
1858 specify extra switches to give the printer program, customize the list
1859 variable @code{lpr-switches}. Its value should be a list of option
1860 strings, each of which should start with @samp{-} (e.g., the option
1861 string @code{"-w80"} specifies a line width of 80 columns). The
1862 default is the empty list, @code{nil}.
1864 @vindex printer-name
1865 @vindex lpr-printer-switch
1866 To specify the printer to use, set the variable @code{printer-name}.
1867 The default, @code{nil}, specifies the default printer. If you set it
1868 to a printer name (a string), that name is passed to @command{lpr}
1869 with the @samp{-P} switch; if you are not using @command{lpr}, you
1870 should specify the switch with @code{lpr-printer-switch}.
1872 @vindex lpr-headers-switches
1873 @vindex lpr-add-switches
1874 The variable @code{lpr-headers-switches} similarly specifies the
1875 extra switches to use to make page headers. The variable
1876 @code{lpr-add-switches} controls whether to supply @samp{-T} and
1877 @samp{-J} options (suitable for @command{lpr}) to the printer program:
1878 @code{nil} means don't add them (this should be the value if your
1879 printer program is not compatible with @command{lpr}).
1882 * PostScript:: Printing buffers or regions as PostScript.
1883 * PostScript Variables:: Customizing the PostScript printing commands.
1884 * Printing Package:: An optional advanced printing interface.
1888 @subsection PostScript Hardcopy
1890 These commands convert buffer contents to PostScript,
1891 either printing it or leaving it in another Emacs buffer.
1894 @item M-x ps-print-buffer
1895 Print hardcopy of the current buffer in PostScript form.
1896 @item M-x ps-print-region
1897 Print hardcopy of the current region in PostScript form.
1898 @item M-x ps-print-buffer-with-faces
1899 Print hardcopy of the current buffer in PostScript form, showing the
1900 faces used in the text by means of PostScript features.
1901 @item M-x ps-print-region-with-faces
1902 Print hardcopy of the current region in PostScript form, showing the
1903 faces used in the text.
1904 @item M-x ps-spool-buffer
1905 Generate and spool a PostScript image for the current buffer text.
1906 @item M-x ps-spool-region
1907 Generate and spool a PostScript image for the current region.
1908 @item M-x ps-spool-buffer-with-faces
1909 Generate and spool a PostScript image for the current buffer, showing the faces used.
1910 @item M-x ps-spool-region-with-faces
1911 Generate and spool a PostScript image for the current region, showing the faces used.
1912 @item M-x ps-despool
1913 Send the spooled PostScript to the printer.
1915 Generate/print PostScript for the current buffer as if handwritten.
1918 @findex ps-print-region
1919 @findex ps-print-buffer
1920 @findex ps-print-region-with-faces
1921 @findex ps-print-buffer-with-faces
1922 The @code{ps-print-buffer} and @code{ps-print-region} commands print
1923 buffer contents in PostScript form. One command prints the entire
1924 buffer; the other, just the region. The commands
1925 @code{ps-print-buffer-with-faces} and
1926 @code{ps-print-region-with-faces} behave similarly, but use PostScript
1927 features to show the faces (fonts and colors) of the buffer text.
1929 Interactively, when you use a prefix argument (@kbd{C-u}), the command
1930 prompts the user for a file name, and saves the PostScript image in that file
1931 instead of sending it to the printer.
1933 @findex ps-spool-region
1934 @findex ps-spool-buffer
1935 @findex ps-spool-region-with-faces
1936 @findex ps-spool-buffer-with-faces
1937 The commands whose names have @samp{spool} instead of @samp{print},
1938 generate the PostScript output in an Emacs buffer instead of sending
1942 Use the command @code{ps-despool} to send the spooled images to the
1943 printer. This command sends the PostScript generated by
1944 @samp{-spool-} commands (see commands above) to the printer. With a
1945 prefix argument (@kbd{C-u}), it prompts for a file name, and saves the
1946 spooled PostScript image in that file instead of sending it to the
1951 @kbd{M-x handwrite} is more frivolous. It generates a PostScript
1952 rendition of the current buffer as a cursive handwritten document. It
1953 can be customized in group @code{handwrite}. This function only
1954 supports ISO 8859-1 characters.
1956 @node PostScript Variables
1957 @subsection Variables for PostScript Hardcopy
1959 @vindex ps-lpr-command
1960 @vindex ps-lpr-switches
1961 @vindex ps-printer-name
1962 All the PostScript hardcopy commands use the variables
1963 @code{ps-lpr-command} and @code{ps-lpr-switches} to specify how to print
1964 the output. @code{ps-lpr-command} specifies the command name to run,
1965 @code{ps-lpr-switches} specifies command line options to use, and
1966 @code{ps-printer-name} specifies the printer. If you don't set the
1967 first two variables yourself, they take their initial values from
1968 @code{lpr-command} and @code{lpr-switches}. If @code{ps-printer-name}
1969 is @code{nil}, @code{printer-name} is used.
1971 @vindex ps-print-header
1972 The variable @code{ps-print-header} controls whether these commands
1973 add header lines to each page---set it to @code{nil} to turn headers
1976 @cindex color emulation on black-and-white printers
1977 @vindex ps-print-color-p
1978 If your printer doesn't support colors, you should turn off color
1979 processing by setting @code{ps-print-color-p} to @code{nil}. By
1980 default, if the display supports colors, Emacs produces hardcopy output
1981 with color information; on black-and-white printers, colors are emulated
1982 with shades of gray. This might produce illegible output, even if your
1983 screen colors only use shades of gray.
1985 Alternatively, you can set @code{ps-print-color-p} to @code{black-white} to
1986 print colors on black/white printers.
1988 @vindex ps-use-face-background
1989 By default, PostScript printing ignores the background colors of the
1990 faces, unless the variable @code{ps-use-face-background} is
1991 non-@code{nil}. This is to avoid unwanted interference with the zebra
1992 stripes and background image/text.
1994 @vindex ps-paper-type
1995 @vindex ps-page-dimensions-database
1996 The variable @code{ps-paper-type} specifies which size of paper to
1997 format for; legitimate values include @code{a4}, @code{a3},
1998 @code{a4small}, @code{b4}, @code{b5}, @code{executive}, @code{ledger},
1999 @code{legal}, @code{letter}, @code{letter-small}, @code{statement},
2000 @code{tabloid}. The default is @code{letter}. You can define
2001 additional paper sizes by changing the variable
2002 @code{ps-page-dimensions-database}.
2004 @vindex ps-landscape-mode
2005 The variable @code{ps-landscape-mode} specifies the orientation of
2006 printing on the page. The default is @code{nil}, which stands for
2007 portrait mode. Any non-@code{nil} value specifies landscape
2010 @vindex ps-number-of-columns
2011 The variable @code{ps-number-of-columns} specifies the number of
2012 columns; it takes effect in both landscape and portrait mode. The
2015 @vindex ps-font-family
2016 @vindex ps-font-size
2017 @vindex ps-font-info-database
2018 The variable @code{ps-font-family} specifies which font family to use
2019 for printing ordinary text. Legitimate values include @code{Courier},
2020 @code{Helvetica}, @code{NewCenturySchlbk}, @code{Palatino} and
2021 @code{Times}. The variable @code{ps-font-size} specifies the size of
2022 the font for ordinary text. It defaults to 8.5 points.
2024 @vindex ps-multibyte-buffer
2025 @cindex Intlfonts for PostScript printing
2026 @cindex fonts for PostScript printing
2027 Emacs supports more scripts and characters than a typical PostScript
2028 printer. Thus, some of the characters in your buffer might not be
2029 printable using the fonts built into your printer. You can augment
2030 the fonts supplied with the printer with those from the GNU Intlfonts
2031 package, or you can instruct Emacs to use Intlfonts exclusively. The
2032 variable @code{ps-multibyte-buffer} controls this: the default value,
2033 @code{nil}, is appropriate for printing @acronym{ASCII} and Latin-1
2034 characters; a value of @code{non-latin-printer} is for printers which
2035 have the fonts for @acronym{ASCII}, Latin-1, Japanese, and Korean
2036 characters built into them. A value of @code{bdf-font} arranges for
2037 the BDF fonts from the Intlfonts package to be used for @emph{all}
2038 characters. Finally, a value of @code{bdf-font-except-latin}
2039 instructs the printer to use built-in fonts for @acronym{ASCII} and Latin-1
2040 characters, and Intlfonts BDF fonts for the rest.
2042 @vindex bdf-directory-list
2043 To be able to use the BDF fonts, Emacs needs to know where to find
2044 them. The variable @code{bdf-directory-list} holds the list of
2045 directories where Emacs should look for the fonts; the default value
2046 includes a single directory @file{/usr/local/share/emacs/fonts/bdf}.
2048 Many other customization variables for these commands are defined and
2049 described in the Lisp files @file{ps-print.el} and @file{ps-mule.el}.
2051 @node Printing Package
2052 @subsection Printing Package
2053 @cindex Printing package
2055 The basic Emacs facilities for printing hardcopy can be extended
2056 using the Printing package. This provides an easy-to-use interface
2057 for choosing what to print, previewing PostScript files before
2058 printing, and setting various printing options such as print headers,
2059 landscape or portrait modes, duplex modes, and so forth. On GNU/Linux
2060 or Unix systems, the Printing package relies on the @file{gs} and
2061 @file{gv} utilities, which are distributed as part of the GhostScript
2062 program. On MS-Windows, the @file{gstools} port of Ghostscript can be
2065 @findex pr-interface
2066 To use the Printing package, add @code{(require 'printing)} to your
2067 init file (@pxref{Init File}), followed by @code{(pr-update-menus)}.
2068 This function replaces the usual printing commands in the menu bar
2069 with a @samp{Printing} submenu that contains various printing options.
2070 You can also type @kbd{M-x pr-interface @key{RET}}; this creates a
2071 @file{*Printing Interface*} buffer, similar to a customization buffer,
2072 where you can set the printing options. After selecting what and how
2073 to print, you start the print job using the @samp{Print} button (click
2074 @kbd{Mouse-2} on it, or move point over it and type @key{RET}). For
2075 further information on the various options, use the @samp{Interface
2079 @section Sorting Text
2082 Emacs provides several commands for sorting text in the buffer. All
2083 operate on the contents of the region.
2084 They divide the text of the region into many @dfn{sort records},
2085 identify a @dfn{sort key} for each record, and then reorder the records
2086 into the order determined by the sort keys. The records are ordered so
2087 that their keys are in alphabetical order, or, for numeric sorting, in
2088 numeric order. In alphabetic sorting, all upper-case letters @samp{A}
2089 through @samp{Z} come before lower-case @samp{a}, in accordance with the
2090 @acronym{ASCII} character sequence.
2092 The various sort commands differ in how they divide the text into sort
2093 records and in which part of each record is used as the sort key. Most of
2094 the commands make each line a separate sort record, but some commands use
2095 paragraphs or pages as sort records. Most of the sort commands use each
2096 entire sort record as its own sort key, but some use only a portion of the
2097 record as the sort key.
2100 @findex sort-paragraphs
2103 @findex sort-numeric-fields
2104 @vindex sort-numeric-base
2106 @item M-x sort-lines
2107 Divide the region into lines, and sort by comparing the entire
2108 text of a line. A numeric argument means sort into descending order.
2110 @item M-x sort-paragraphs
2111 Divide the region into paragraphs, and sort by comparing the entire
2112 text of a paragraph (except for leading blank lines). A numeric
2113 argument means sort into descending order.
2115 @item M-x sort-pages
2116 Divide the region into pages, and sort by comparing the entire
2117 text of a page (except for leading blank lines). A numeric
2118 argument means sort into descending order.
2120 @item M-x sort-fields
2121 Divide the region into lines, and sort by comparing the contents of
2122 one field in each line. Fields are defined as separated by
2123 whitespace, so the first run of consecutive non-whitespace characters
2124 in a line constitutes field 1, the second such run constitutes field
2127 Specify which field to sort by with a numeric argument: 1 to sort by
2128 field 1, etc. A negative argument means count fields from the right
2129 instead of from the left; thus, minus 1 means sort by the last field.
2130 If several lines have identical contents in the field being sorted, they
2131 keep the same relative order that they had in the original buffer.
2133 @item M-x sort-numeric-fields
2134 Like @kbd{M-x sort-fields} except the specified field is converted
2135 to an integer for each line, and the numbers are compared. @samp{10}
2136 comes before @samp{2} when considered as text, but after it when
2137 considered as a number. By default, numbers are interpreted according
2138 to @code{sort-numeric-base}, but numbers beginning with @samp{0x} or
2139 @samp{0} are interpreted as hexadecimal and octal, respectively.
2141 @item M-x sort-columns
2142 Like @kbd{M-x sort-fields} except that the text within each line
2143 used for comparison comes from a fixed range of columns. With a
2144 prefix argument, sort in reverse order. See below for more details
2147 @findex reverse-region
2148 @item M-x reverse-region
2149 Reverse the order of the lines in the region. This is useful for
2150 sorting into descending order by fields, since those sort
2151 commands do not have a feature for doing that.
2154 For example, if the buffer contains this:
2157 On systems where clash detection (locking of files being edited) is
2158 implemented, Emacs also checks the first time you modify a buffer
2159 whether the file has changed on disk since it was last visited or
2160 saved. If it has, you are asked to confirm that you want to change
2165 applying @kbd{M-x sort-lines} to the entire buffer produces this:
2168 On systems where clash detection (locking of files being edited) is
2169 implemented, Emacs also checks the first time you modify a buffer
2170 saved. If it has, you are asked to confirm that you want to change
2172 whether the file has changed on disk since it was last visited or
2176 where the upper-case @samp{O} sorts before all lower-case letters. If
2177 you use @kbd{C-u 2 M-x sort-fields} instead, you get this:
2180 implemented, Emacs also checks the first time you modify a buffer
2181 saved. If it has, you are asked to confirm that you want to change
2183 On systems where clash detection (locking of files being edited) is
2184 whether the file has changed on disk since it was last visited or
2188 where the sort keys were @samp{Emacs}, @samp{If}, @samp{buffer},
2189 @samp{systems} and @samp{the}.
2191 @findex sort-columns
2192 @kbd{M-x sort-columns} requires more explanation. You specify the
2193 columns by putting point at one of the columns and the mark at the other
2194 column. Because this means you cannot put point or the mark at the
2195 beginning of the first line of the text you want to sort, this command
2196 uses an unusual definition of ``region'': all of the line point is in is
2197 considered part of the region, and so is all of the line the mark is in,
2198 as well as all the lines in between.
2200 For example, to sort a table by information found in columns 10 to 15,
2201 you could put the mark on column 10 in the first line of the table, and
2202 point on column 15 in the last line of the table, and then run
2203 @code{sort-columns}. Equivalently, you could run it with the mark on
2204 column 15 in the first line and point on column 10 in the last line.
2206 This can be thought of as sorting the rectangle specified by point and
2207 the mark, except that the text on each line to the left or right of the
2208 rectangle moves along with the text inside the rectangle.
2211 @vindex sort-fold-case
2212 Many of the sort commands ignore case differences when comparing, if
2213 @code{sort-fold-case} is non-@code{nil}.
2215 @c Picture Mode documentation
2217 @include picture-xtra.texi
2221 @node Editing Binary Files
2222 @section Editing Binary Files
2226 @cindex editing binary files
2228 There is a special major mode for editing binary files: Hexl mode. To
2229 use it, use @kbd{M-x hexl-find-file} instead of @kbd{C-x C-f} to visit
2230 the file. This command converts the file's contents to hexadecimal and
2231 lets you edit the translation. When you save the file, it is converted
2232 automatically back to binary.
2234 You can also use @kbd{M-x hexl-mode} to translate an existing buffer
2235 into hex. This is useful if you visit a file normally and then discover
2236 it is a binary file.
2238 Ordinary text characters overwrite in Hexl mode. This is to reduce
2239 the risk of accidentally spoiling the alignment of data in the file.
2240 There are special commands for insertion. Here is a list of the
2241 commands of Hexl mode:
2243 @c I don't think individual index entries for these commands are useful--RMS.
2246 Insert a byte with a code typed in decimal.
2249 Insert a byte with a code typed in octal.
2252 Insert a byte with a code typed in hex.
2255 Move to the beginning of a 1k-byte page.
2258 Move to the end of a 1k-byte page.
2261 Move to an address specified in hex.
2264 Move to an address specified in decimal.
2267 Leave Hexl mode, going back to the major mode this buffer had before you
2268 invoked @code{hexl-mode}.
2272 Other Hexl commands let you insert strings (sequences) of binary
2273 bytes, move by @code{short}s or @code{int}s, etc.; type @kbd{C-h a
2274 hexl-@key{RET}} for details.
2277 @node Saving Emacs Sessions
2278 @section Saving Emacs Sessions
2279 @cindex saving sessions
2280 @cindex restore session
2281 @cindex remember editing session
2282 @cindex reload files
2285 @vindex desktop-restore-frames
2286 Use the desktop library to save the state of Emacs from one session
2287 to another. Once you save the Emacs @dfn{desktop}---the buffers,
2288 their file names, major modes, buffer positions, and so on---then
2289 subsequent Emacs sessions reload the saved desktop. By default,
2290 the desktop also tries to save the frame and window configuration.
2291 To disable this, set @code{desktop-restore-frames} to @code{nil}.
2292 (See that variable's documentation for some related options
2293 that you can customize to fine-tune this behavior.)
2295 @findex desktop-save
2296 @vindex desktop-save-mode
2297 You can save the desktop manually with the command @kbd{M-x
2298 desktop-save}. You can also enable automatic saving of the desktop
2299 when you exit Emacs, and automatic restoration of the last saved
2300 desktop when Emacs starts: use the Customization buffer (@pxref{Easy
2301 Customization}) to set @code{desktop-save-mode} to @code{t} for future
2302 sessions, or add this line in your init file (@pxref{Init File}):
2305 (desktop-save-mode 1)
2308 @vindex desktop-auto-save-timeout
2310 When @code{desktop-save-mode} is active and the desktop file exists,
2311 Emacs auto-saves it every @code{desktop-auto-save-timeout}
2312 seconds, if that is non-@code{nil} and non-zero.
2314 @findex desktop-change-dir
2315 @findex desktop-revert
2316 @vindex desktop-path
2317 If you turn on @code{desktop-save-mode} in your init file, then when
2318 Emacs starts, it looks for a saved desktop in the current directory.
2319 (More precisely, it looks in the directories specified by
2320 @var{desktop-path}, and uses the first desktop it finds.)
2321 Thus, you can have separate saved desktops in different directories,
2322 and the starting directory determines which one Emacs reloads. You
2323 can save the current desktop and reload one saved in another directory
2324 by typing @kbd{M-x desktop-change-dir}. Typing @kbd{M-x
2325 desktop-revert} reverts to the desktop previously reloaded.
2327 Specify the option @samp{--no-desktop} on the command line when you
2328 don't want it to reload any saved desktop. This turns off
2329 @code{desktop-save-mode} for the current session. Starting Emacs with
2330 the @samp{--no-init-file} option also disables desktop reloading,
2331 since it bypasses the init file, where @code{desktop-save-mode} is
2334 @vindex desktop-restore-eager
2335 By default, all the buffers in the desktop are restored at one go.
2336 However, this may be slow if there are a lot of buffers in the
2337 desktop. You can specify the maximum number of buffers to restore
2338 immediately with the variable @code{desktop-restore-eager}; the
2339 remaining buffers are restored lazily, when Emacs is idle.
2341 @findex desktop-clear
2342 @vindex desktop-globals-to-clear
2343 @vindex desktop-clear-preserve-buffers-regexp
2344 Type @kbd{M-x desktop-clear} to empty the Emacs desktop. This kills
2345 all buffers except for internal ones, and clears the global variables
2346 listed in @code{desktop-globals-to-clear}. If you want this to
2347 preserve certain buffers, customize the variable
2348 @code{desktop-clear-preserve-buffers-regexp}, whose value is a regular
2349 expression matching the names of buffers not to kill.
2351 If you want to save minibuffer history from one session to
2352 another, use the @code{savehist} library.
2354 @node Recursive Edit
2355 @section Recursive Editing Levels
2356 @cindex recursive editing level
2357 @cindex editing level, recursive
2359 A @dfn{recursive edit} is a situation in which you are using Emacs
2360 commands to perform arbitrary editing while in the middle of another
2361 Emacs command. For example, when you type @kbd{C-r} inside of a
2362 @code{query-replace}, you enter a recursive edit in which you can change
2363 the current buffer. On exiting from the recursive edit, you go back to
2364 the @code{query-replace}. @xref{Query Replace}.
2367 @findex exit-recursive-edit
2368 @cindex exiting recursive edit
2369 @dfn{Exiting} the recursive edit means returning to the unfinished
2370 command, which continues execution. The command to exit is @kbd{C-M-c}
2371 (@code{exit-recursive-edit}).
2373 You can also @dfn{abort} the recursive edit. This is like exiting,
2374 but also quits the unfinished command immediately. Use the command
2375 @kbd{C-]} (@code{abort-recursive-edit}) to do this. @xref{Quitting}.
2377 The mode line shows you when you are in a recursive edit by displaying
2378 square brackets around the parentheses that always surround the major and
2379 minor mode names. Every window's mode line shows this in the same way,
2380 since being in a recursive edit is true of Emacs as a whole rather than
2381 any particular window or buffer.
2383 It is possible to be in recursive edits within recursive edits. For
2384 example, after typing @kbd{C-r} in a @code{query-replace}, you may type a
2385 command that enters the debugger. This begins a recursive editing level
2386 for the debugger, within the recursive editing level for @kbd{C-r}.
2387 Mode lines display a pair of square brackets for each recursive editing
2388 level currently in progress.
2390 Exiting the inner recursive edit (such as with the debugger @kbd{c}
2391 command) resumes the command running in the next level up. When that
2392 command finishes, you can then use @kbd{C-M-c} to exit another recursive
2393 editing level, and so on. Exiting applies to the innermost level only.
2394 Aborting also gets out of only one level of recursive edit; it returns
2395 immediately to the command level of the previous recursive edit. If you
2396 wish, you can then abort the next recursive editing level.
2398 Alternatively, the command @kbd{M-x top-level} aborts all levels of
2399 recursive edits, returning immediately to the top-level command
2400 reader. It also exits the minibuffer, if it is active.
2402 The text being edited inside the recursive edit need not be the same text
2403 that you were editing at top level. It depends on what the recursive edit
2404 is for. If the command that invokes the recursive edit selects a different
2405 buffer first, that is the buffer you will edit recursively. In any case,
2406 you can switch buffers within the recursive edit in the normal manner (as
2407 long as the buffer-switching keys have not been rebound). You could
2408 probably do all the rest of your editing inside the recursive edit,
2409 visiting files and all. But this could have surprising effects (such as
2410 stack overflow) from time to time. So remember to exit or abort the
2411 recursive edit when you no longer need it.
2413 In general, we try to minimize the use of recursive editing levels in
2414 GNU Emacs. This is because they constrain you to go back in a
2415 particular order---from the innermost level toward the top level. When
2416 possible, we present different activities in separate buffers so that
2417 you can switch between them as you please. Some commands switch to a
2418 new major mode which provides a command to switch back. These
2419 approaches give you more flexibility to go back to unfinished tasks in
2420 the order you choose.
2423 @c Apart from edt and viper, this is all obsolete.
2424 @c (Can't believe we were saying "most other editors" into 2014!)
2425 @c There seems no point having a node just for those, which both have
2426 @c their own manuals.
2429 @cindex emulating other editors
2430 @cindex other editors
2435 GNU Emacs can be programmed to emulate (more or less) most other
2436 editors. Standard facilities can emulate these:
2439 @item CRiSP/Brief (PC editor)
2441 @vindex crisp-override-meta-x
2442 @findex scroll-all-mode
2444 @cindex Brief emulation
2445 @cindex emulation of Brief
2447 @kbd{M-x crisp-mode} enables key bindings to emulate the CRiSP/Brief
2448 editor. Note that this rebinds @kbd{M-x} to exit Emacs unless you set
2449 the variable @code{crisp-override-meta-x}. You can also use the
2450 command @kbd{M-x scroll-all-mode} or set the variable
2451 @code{crisp-load-scroll-all} to emulate CRiSP's scroll-all feature
2452 (scrolling all windows together).
2454 @item EDT (DEC VMS editor)
2455 @findex edt-emulation-on
2456 @findex edt-emulation-off
2457 Turn on EDT emulation with @kbd{M-x edt-emulation-on}; restore normal
2458 command bindings with @kbd{M-x edt-emulation-off}.
2460 Most of the EDT emulation commands are keypad keys, and most standard
2461 Emacs key bindings are still available. The EDT emulation rebindings
2462 are done in the global keymap, so there is no problem switching
2463 buffers or major modes while in EDT emulation.
2465 @item TPU (DEC VMS editor)
2468 @kbd{M-x tpu-edt-on} turns on emulation of the TPU editor emulating EDT.
2470 @item vi (Berkeley editor)
2472 Viper is an emulator for vi. It implements several levels of
2473 emulation; level 1 is closest to vi itself, while level 5 departs
2474 somewhat from strict emulation to take advantage of the capabilities of
2475 Emacs. To invoke Viper, type @kbd{M-x viper-mode}; it will guide you
2476 the rest of the way and ask for the emulation level. @inforef{Top,
2479 @item vi (another emulator)
2481 @kbd{M-x vi-mode} enters a major mode that replaces the previously
2482 established major mode. All of the vi commands that, in real vi, enter
2483 input mode are programmed instead to return to the previous major
2484 mode. Thus, ordinary Emacs serves as vi's input mode.
2486 Because vi emulation works through major modes, it does not work
2487 to switch buffers during emulation. Return to normal Emacs first.
2489 If you plan to use vi emulation much, you probably want to bind a key
2490 to the @code{vi-mode} command.
2492 @item vi (alternate emulator)
2494 @kbd{M-x vip-mode} invokes another vi emulator, said to resemble real vi
2495 more thoroughly than @kbd{M-x vi-mode}. Input mode in this emulator
2496 is changed from ordinary Emacs so you can use @key{ESC} to go back to
2497 emulated vi command mode. To get from emulated vi command mode back to
2498 ordinary Emacs, type @kbd{C-z}.
2500 This emulation does not work through major modes, and it is possible
2501 to switch buffers in various ways within the emulator. It is not
2502 so necessary to assign a key to the command @code{vip-mode} as
2503 it is with @code{vi-mode} because terminating insert mode does
2506 @inforef{Top, VIP, vip}, for full information.
2508 @item WordStar (old wordprocessor)
2509 @findex wordstar-mode
2510 @kbd{M-x wordstar-mode} provides a major mode with WordStar-like
2517 @section Hyperlinking and Navigation Features
2519 The following subsections describe convenience features for handling
2520 URLs and other types of links occurring in Emacs buffer text.
2523 * Browse-URL:: Following URLs.
2524 * Goto Address mode:: Activating URLs.
2525 * FFAP:: Finding files etc. at point.
2529 @subsection Following URLs
2530 @cindex World Wide Web
2533 @findex browse-url-at-point
2534 @findex browse-url-at-mouse
2539 @item M-x browse-url @key{RET} @var{url} @key{RET}
2540 Load a URL into a Web browser.
2543 The Browse-URL package allows you to easily follow URLs from within
2544 Emacs. Most URLs are followed by invoking a web browser;
2545 @samp{mailto:} URLs are followed by invoking the @code{compose-mail}
2546 Emacs command to send mail to the specified address (@pxref{Sending
2549 The command @kbd{M-x browse-url} prompts for a URL, and follows it.
2550 If point is located near a plausible URL, that URL is offered as the
2551 default. The Browse-URL package also provides other commands which
2552 you might like to bind to keys, such as @code{browse-url-at-point} and
2553 @code{browse-url-at-mouse}.
2555 @vindex browse-url-mailto-function
2556 @vindex browse-url-browser-function
2557 You can customize Browse-URL's behavior via various options in the
2558 @code{browse-url} Customize group. In particular, the option
2559 @code{browse-url-mailto-function} lets you define how to follow
2560 @samp{mailto:} URLs, while @code{browse-url-browser-function} lets you
2561 define how to follow other types of URLs. For more information, view
2562 the package commentary by typing @kbd{C-h P browse-url @key{RET}}.
2564 @node Goto Address mode
2565 @subsection Activating URLs
2566 @findex goto-address-mode
2567 @cindex mode, Goto Address
2568 @cindex Goto Address mode
2569 @cindex URLs, activating
2572 @item M-x goto-address-mode
2573 Activate URLs and e-mail addresses in the current buffer.
2576 @kindex C-c RET @r{(Goto Address mode)}
2577 @findex goto-address-at-point
2578 You can make Emacs mark out URLs specially in the current buffer, by
2579 typing @kbd{M-x goto-address-mode}. When this buffer-local minor mode
2580 is enabled, it finds all the URLs in the buffer, highlights them, and
2581 turns them into clickable buttons. You can follow the URL by typing
2582 @kbd{C-c @key{RET}} (@code{goto-address-at-point}) while point is on
2583 its text; or by clicking with @kbd{Mouse-2}, or by clicking
2584 @kbd{Mouse-1} quickly (@pxref{Mouse References}). Following a URL is
2585 done by calling @code{browse-url} as a subroutine
2586 (@pxref{Browse-URL}).
2588 It can be useful to add @code{goto-address-mode} to mode hooks and
2589 hooks for displaying an incoming message
2590 (e.g., @code{rmail-show-message-hook} for Rmail, and
2591 @code{mh-show-mode-hook} for MH-E). This is not needed for Gnus,
2592 which has a similar feature of its own.
2595 @subsection Finding Files and URLs at Point
2596 @findex find-file-at-point
2598 @findex dired-at-point
2601 @cindex finding file at point
2603 The FFAP package replaces certain key bindings for finding files,
2604 such as @kbd{C-x C-f}, with commands that provide more sensitive
2605 defaults. These commands behave like the ordinary ones when given a
2606 prefix argument. Otherwise, they get the default file name or URL
2607 from the text around point. If what is found in the buffer has the
2608 form of a URL rather than a file name, the commands use
2609 @code{browse-url} to view it (@pxref{Browse-URL}).
2611 This feature is useful for following references in mail or news
2612 buffers, @file{README} files, @file{MANIFEST} files, and so on. For
2613 more information, view the package commentary by typing @kbd{C-h P
2616 @cindex FFAP minor mode
2618 To enable FFAP, type @kbd{M-x ffap-bindings}. This makes the
2619 following key bindings, and also installs hooks for additional FFAP
2620 functionality in Rmail, Gnus and VM article buffers.
2623 @item C-x C-f @var{filename} @key{RET}
2624 @kindex C-x C-f @r{(FFAP)}
2625 Find @var{filename}, guessing a default from text around point
2626 (@code{find-file-at-point}).
2628 @kindex C-x C-r @r{(FFAP)}
2629 @code{ffap-read-only}, analogous to @code{find-file-read-only}.
2631 @kindex C-x C-v @r{(FFAP)}
2632 @code{ffap-alternate-file}, analogous to @code{find-alternate-file}.
2633 @item C-x d @var{directory} @key{RET}
2634 @kindex C-x d @r{(FFAP)}
2635 Start Dired on @var{directory}, defaulting to the directory name at
2636 point (@code{dired-at-point}).
2638 @code{ffap-list-directory}, analogous to @code{list-directory}.
2640 @kindex C-x 4 f @r{(FFAP)}
2641 @code{ffap-other-window}, analogous to @code{find-file-other-window}.
2643 @code{ffap-read-only-other-window}, analogous to
2644 @code{find-file-read-only-other-window}.
2646 @code{ffap-dired-other-window}, like @code{dired-other-window}.
2648 @kindex C-x 5 f @r{(FFAP)}
2649 @code{ffap-other-frame}, analogous to @code{find-file-other-frame}.
2651 @code{ffap-read-only-other-frame}, analogous to
2652 @code{find-file-read-only-other-frame}.
2654 @code{ffap-dired-other-frame}, analogous to @code{dired-other-frame}.
2656 Search buffer for next file name or URL, then find that file or URL.
2658 @kindex S-Mouse-3 @r{(FFAP)}
2659 @code{ffap-at-mouse} finds the file guessed from text around the position
2662 @kindex C-S-Mouse-3 @r{(FFAP)}
2663 Display a menu of files and URLs mentioned in current buffer, then
2664 find the one you select (@code{ffap-menu}).
2668 @section Other Amusements
2671 @findex animate-birthday-present
2673 The @code{animate} package makes text dance (e.g., @kbd{M-x
2674 animate-birthday-present}).
2680 @kbd{M-x blackbox}, @kbd{M-x mpuz} and @kbd{M-x 5x5} are puzzles.
2681 @code{blackbox} challenges you to determine the location of objects
2682 inside a box by tomography. @code{mpuz} displays a multiplication
2683 puzzle with letters standing for digits in a code that you must
2684 guess---to guess a value, type a letter and then the digit you think it
2685 stands for. The aim of @code{5x5} is to fill in all the squares.
2688 @kbd{M-x bubbles} is a game in which the object is to remove as many
2689 bubbles as you can in the smallest number of moves.
2693 @cindex cryptanalysis
2694 @kbd{M-x decipher} helps you to cryptanalyze a buffer which is
2695 encrypted in a simple monoalphabetic substitution cipher.
2697 @findex dissociated-press
2698 @kbd{M-x dissociated-press} scrambles the text in the current Emacs
2699 buffer, word by word or character by character, writing its output to
2700 a buffer named @file{*Dissociation*}. A positive argument tells it to
2701 operate character by character, and specifies the number of overlap
2702 characters. A negative argument tells it to operate word by word, and
2703 specifies the number of overlap words. Dissociated Press produces
2704 results fairly like those of a Markov chain, but is however, an
2705 independent, ignoriginal invention; it techniquitously copies several
2706 consecutive characters from the sample text between random jumps,
2707 unlike a Markov chain which would jump randomly after each word or
2708 character. Keep dissociwords out of your documentation, if you want
2709 it to be well userenced and properbose.
2712 @kbd{M-x dunnet} runs a text-based adventure game.
2716 If you want a little more personal involvement, try @kbd{M-x gomoku},
2717 which plays the game Go Moku with you.
2719 @cindex tower of Hanoi
2721 If you are a little bit bored, you can try @kbd{M-x hanoi}. If you are
2722 considerably bored, give it a numeric argument. If you are very, very
2723 bored, try an argument of 9. Sit back and watch.
2727 @kbd{M-x life} runs Conway's Game of Life cellular automaton.
2730 @cindex landmark game
2731 @kbd{M-x landmark} runs a relatively non-participatory game in which
2732 a robot attempts to maneuver towards a tree at the center of the
2733 window based on unique olfactory cues from each of the four
2736 @findex morse-region
2737 @findex unmorse-region
2740 @cindex --/---/.-./.../.
2741 @kbd{M-x morse-region} converts the text in the region to Morse
2742 code; @kbd{M-x unmorse-region} converts it back. @kbd{M-x
2743 nato-region} converts the text in the region to NATO phonetic
2744 alphabet; @kbd{M-x denato-region} converts it back.
2752 @kbd{M-x pong}, @kbd{M-x snake} and @kbd{M-x tetris} are
2753 implementations of the well-known Pong, Snake and Tetris games.
2757 @kbd{M-x solitaire} plays a game of solitaire in which you jump pegs
2761 The command @kbd{M-x zone} plays games with the display when Emacs
2766 Finally, if you find yourself frustrated, try describing your
2767 problems to the famous psychotherapist Eliza. Just do @kbd{M-x
2768 doctor}. End each input by typing @key{RET} twice.