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6bf7aab6 | 1 | @c This is part of the Emacs manual. |
b65d8176 | 2 | @c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2000, 2001, |
4e6835db | 3 | @c 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc. |
6bf7aab6 DL |
4 | @c See file emacs.texi for copying conditions. |
5 | @node Buffers, Windows, Files, Top | |
6 | @chapter Using Multiple Buffers | |
7 | ||
8 | @cindex buffers | |
9 | The text you are editing in Emacs resides in an object called a | |
10 | @dfn{buffer}. Each time you visit a file, a buffer is created to hold the | |
11 | file's text. Each time you invoke Dired, a buffer is created to hold the | |
12 | directory listing. If you send a message with @kbd{C-x m}, a buffer named | |
13 | @samp{*mail*} is used to hold the text of the message. When you ask for a | |
14 | command's documentation, that appears in a buffer called @samp{*Help*}. | |
15 | ||
16 | @cindex selected buffer | |
17 | @cindex current buffer | |
ab25a0c7 RS |
18 | At any time, one and only one buffer is @dfn{current}. It is also |
19 | called the @dfn{selected buffer}. Often we say that a command operates on | |
6bf7aab6 | 20 | ``the buffer'' as if there were only one; but really this means that the |
ab25a0c7 | 21 | command operates on the current buffer (most commands do). |
6bf7aab6 | 22 | |
85d6c6e7 RS |
23 | When Emacs has multiple windows, each window has its own chosen |
24 | buffer and displays it; at any time, only one of the windows is | |
ab25a0c7 | 25 | selected, and its chosen buffer is the current buffer. Each window's |
85d6c6e7 RS |
26 | mode line normally displays the name of the window's chosen buffer |
27 | (@pxref{Windows}). | |
6bf7aab6 DL |
28 | |
29 | Each buffer has a name, which can be of any length, and you can select | |
30 | any buffer by giving its name. Most buffers are made by visiting files, | |
31 | and their names are derived from the files' names. But you can also create | |
32 | an empty buffer with any name you want. A newly started Emacs has a buffer | |
33 | named @samp{*scratch*} which can be used for evaluating Lisp expressions in | |
34 | Emacs. The distinction between upper and lower case matters in buffer | |
35 | names. | |
36 | ||
37 | Each buffer records individually what file it is visiting, whether it is | |
38 | modified, and what major mode and minor modes are in effect in it | |
39 | (@pxref{Major Modes}). Any Emacs variable can be made @dfn{local to} a | |
40 | particular buffer, meaning its value in that buffer can be different from | |
41 | the value in other buffers. @xref{Locals}. | |
42 | ||
dc53c88b EZ |
43 | @cindex buffer size, maximum |
44 | A buffer's size cannot be larger than some maximum, which is defined | |
83692ea3 EZ |
45 | by the largest buffer position representable by the @dfn{Emacs integer} |
46 | data type. This is because Emacs tracks buffer positions using that | |
041aabd8 | 47 | data type. For 32-bit machines, the largest buffer size is 256 |
83692ea3 | 48 | megabytes. |
dc53c88b | 49 | |
6bf7aab6 DL |
50 | @menu |
51 | * Select Buffer:: Creating a new buffer or reselecting an old one. | |
52 | * List Buffers:: Getting a list of buffers that exist. | |
53 | * Misc Buffer:: Renaming; changing read-onlyness; copying text. | |
54 | * Kill Buffer:: Killing buffers you no longer need. | |
55 | * Several Buffers:: How to go through the list of all buffers | |
56 | and operate variously on several of them. | |
177c0ea7 | 57 | * Indirect Buffers:: An indirect buffer shares the text of another buffer. |
b54346bc DL |
58 | * Buffer Convenience:: Convenience and customization features for |
59 | buffer handling. | |
6bf7aab6 DL |
60 | @end menu |
61 | ||
62 | @node Select Buffer | |
63 | @section Creating and Selecting Buffers | |
64 | @cindex change buffers | |
65 | @cindex switch buffers | |
66 | ||
67 | @table @kbd | |
68 | @item C-x b @var{buffer} @key{RET} | |
69 | Select or create a buffer named @var{buffer} (@code{switch-to-buffer}). | |
70 | @item C-x 4 b @var{buffer} @key{RET} | |
71 | Similar, but select @var{buffer} in another window | |
72 | (@code{switch-to-buffer-other-window}). | |
73 | @item C-x 5 b @var{buffer} @key{RET} | |
74 | Similar, but select @var{buffer} in a separate frame | |
75 | (@code{switch-to-buffer-other-frame}). | |
160bde9c LT |
76 | @item C-x @key{LEFT} |
77 | Select the previous buffer in the list of existing buffers. | |
78 | @item C-x @key{RIGHT} | |
79 | Select the next buffer in the list of existing buffers. | |
ac2c0786 LT |
80 | @item C-u M-g M-g |
81 | @itemx C-u M-g g | |
82 | Read a number @var{n} and move to line @var{n} in the most recently | |
83 | selected buffer other than the current buffer. | |
6bf7aab6 DL |
84 | @end table |
85 | ||
6bf7aab6 DL |
86 | @kindex C-x b |
87 | @findex switch-to-buffer | |
88 | To select the buffer named @var{bufname}, type @kbd{C-x b @var{bufname} | |
89 | @key{RET}}. This runs the command @code{switch-to-buffer} with argument | |
a3053e27 RS |
90 | @var{bufname}. You can use completion to enter the buffer |
91 | name (@pxref{Completion}). An empty argument to @kbd{C-x b} | |
ab25a0c7 RS |
92 | specifies the buffer that was current most recently among those not |
93 | now displayed in any window. | |
6bf7aab6 | 94 | |
7354ca01 RS |
95 | @kindex C-x @key{LEFT} |
96 | @kindex C-x @key{RIGHT} | |
97 | @findex next-buffer | |
a3700ef7 | 98 | @findex previous-buffer |
7354ca01 RS |
99 | For conveniently switching between a few buffers, use the commands |
100 | @kbd{C-x @key{LEFT}} and @kbd{C-x @key{RIGHT}}. @kbd{C-x @key{RIGHT}} | |
a3700ef7 KL |
101 | (@code{previous-buffer}) selects the previous buffer (following the order |
102 | of most recent selection in the current frame), while @kbd{C-x @key{LEFT}} | |
7354ca01 RS |
103 | (@code{next-buffer}) moves through buffers in the reverse direction. |
104 | ||
8f7cad1f EZ |
105 | @kindex C-x 4 b |
106 | @findex switch-to-buffer-other-window | |
107 | @vindex even-window-heights | |
108 | To select a buffer in a window other than the current one, type | |
109 | @kbd{C-x 4 b @var{bufname} @key{RET}}. This runs the command | |
110 | @code{switch-to-buffer-other-window} which displays the buffer | |
111 | @var{bufname} in another window. By default, if displaying the buffer | |
112 | causes two vertically adjacent windows to be displayed, the heights of | |
113 | those windows are evened out; to countermand that and preserve the | |
114 | window configuration, set the variable @code{even-window-heights} to | |
115 | @code{nil}. | |
116 | ||
117 | @kindex C-x 5 b | |
118 | @findex switch-to-buffer-other-frame | |
119 | Similarly, @kbd{C-x 5 b @var{buffer} @key{RET}} runs the command | |
120 | @code{switch-to-buffer-other-frame} which selects a buffer in another | |
121 | frame. | |
122 | ||
123 | @vindex display-buffer-reuse-frames | |
124 | You can control how certain buffers are handled by these commands by | |
125 | customizing the variables @code{special-display-buffer-names}, | |
126 | @code{special-display-regexps}, @code{same-window-buffer-names}, and | |
127 | @code{same-window-regexps}. See @ref{Force Same Window}, and | |
128 | @ref{Special Buffer Frames}, for more about these variables. In | |
129 | addition, if the value of @code{display-buffer-reuse-frames} is | |
130 | non-@code{nil}, and the buffer you want to switch to is already | |
a3053e27 | 131 | displayed in some frame, Emacs will just raise that frame. |
8f7cad1f | 132 | |
6bf7aab6 DL |
133 | Most buffers are created by visiting files, or by Emacs commands that |
134 | want to display some text, but you can also create a buffer explicitly | |
135 | by typing @kbd{C-x b @var{bufname} @key{RET}}. This makes a new, empty | |
136 | buffer that is not visiting any file, and selects it for editing. Such | |
137 | buffers are used for making notes to yourself. If you try to save one, | |
138 | you are asked for the file name to use. The new buffer's major mode is | |
139 | determined by the value of @code{default-major-mode} (@pxref{Major | |
140 | Modes}). | |
141 | ||
142 | Note that @kbd{C-x C-f}, and any other command for visiting a file, | |
143 | can also be used to switch to an existing file-visiting buffer. | |
144 | @xref{Visiting}. | |
145 | ||
ac2c0786 LT |
146 | @kbd{C-u M-g M-g}, that is @code{goto-line} with a prefix argument |
147 | of just @kbd{C-u}, reads a number @var{n} using the minibuffer, | |
148 | selects the most recently selected buffer other than the current | |
149 | buffer in another window, and then moves point to the beginning of | |
150 | line number @var{n} in that buffer. This is mainly useful in a buffer | |
151 | that refers to line numbers in another buffer: if point is on or just | |
152 | after a number, @code{goto-line} uses that number as the default for | |
153 | @var{n}. Note that prefix arguments other than just @kbd{C-u} behave | |
154 | differently. @kbd{C-u 4 M-g M-g} goes to line 4 in the @emph{current} | |
155 | buffer, without reading a number from the minibuffer. (Remember that | |
156 | @kbd{M-g M-g} without prefix argument reads a number @var{n} and then | |
157 | moves to line number @var{n} in the current buffer.) | |
158 | ||
6bf7aab6 DL |
159 | Emacs uses buffer names that start with a space for internal purposes. |
160 | It treats these buffers specially in minor ways---for example, by | |
161 | default they do not record undo information. It is best to avoid using | |
162 | such buffer names yourself. | |
163 | ||
164 | @node List Buffers | |
165 | @section Listing Existing Buffers | |
166 | ||
167 | @table @kbd | |
168 | @item C-x C-b | |
169 | List the existing buffers (@code{list-buffers}). | |
170 | @end table | |
171 | ||
172 | @cindex listing current buffers | |
173 | @kindex C-x C-b | |
174 | @findex list-buffers | |
7354ca01 RS |
175 | To display a list of existing buffers, type @kbd{C-x C-b}. Each |
176 | line in the list shows one buffer's name, major mode and visited file. | |
177 | The buffers are listed in the order that they were current; the | |
6bf7aab6 DL |
178 | buffers that were current most recently come first. |
179 | ||
a3053e27 RS |
180 | @samp{*} in the first field of a line indicates the buffer is |
181 | ``modified.'' If several buffers are modified, it may be time to save | |
182 | some with @kbd{C-x s} (@pxref{Save Commands}). @samp{%} indicates a | |
183 | read-only buffer. @samp{.} marks the current buffer. Here is an | |
184 | example of a buffer list:@refill | |
6bf7aab6 DL |
185 | |
186 | @smallexample | |
b1a25f96 | 187 | CRM Buffer Size Mode File |
6105130d MR |
188 | . * .emacs 3294 Emacs-Lisp ~/.emacs |
189 | % *Help* 101 Help | |
517b2c37 JB |
190 | search.c 86055 C ~/cvs/emacs/src/search.c |
191 | % src 20959 Dired by name ~/cvs/emacs/src/ | |
6105130d | 192 | * *mail* 42 Mail |
517b2c37 JB |
193 | % HELLO 1607 Fundamental ~/cvs/emacs/etc/HELLO |
194 | % NEWS 481184 Outline ~/cvs/emacs/etc/NEWS | |
195 | *scratch* 191 Lisp Interaction | |
517b2c37 | 196 | * *Messages* 1554 Fundamental |
6bf7aab6 DL |
197 | @end smallexample |
198 | ||
199 | @noindent | |
564ee37b | 200 | Note that the buffer @samp{*Help*} was made by a help request; it is |
6105130d MR |
201 | not visiting any file. The buffer @code{src} was made by Dired on the |
202 | directory @file{~/cvs/emacs/src/}. You can list only buffers that are | |
a3053e27 | 203 | visiting files by giving the command a prefix argument, as in |
564ee37b | 204 | @kbd{C-u C-x C-b}. |
6bf7aab6 | 205 | |
7354ca01 | 206 | @code{list-buffers} omits buffers whose names begin with a space, |
4081af2f EZ |
207 | unless they visit files: such buffers are used internally by Emacs. |
208 | ||
6bf7aab6 DL |
209 | @need 2000 |
210 | @node Misc Buffer | |
211 | @section Miscellaneous Buffer Operations | |
212 | ||
213 | @table @kbd | |
214 | @item C-x C-q | |
8f980b27 | 215 | Toggle read-only status of buffer (@code{toggle-read-only}). |
6bf7aab6 DL |
216 | @item M-x rename-buffer @key{RET} @var{name} @key{RET} |
217 | Change the name of the current buffer. | |
218 | @item M-x rename-uniquely | |
219 | Rename the current buffer by adding @samp{<@var{number}>} to the end. | |
220 | @item M-x view-buffer @key{RET} @var{buffer} @key{RET} | |
221 | Scroll through buffer @var{buffer}. | |
222 | @end table | |
223 | ||
224 | @kindex C-x C-q | |
6bf7aab6 DL |
225 | @vindex buffer-read-only |
226 | @cindex read-only buffer | |
227 | A buffer can be @dfn{read-only}, which means that commands to change | |
564ee37b RS |
228 | its contents are not allowed. The mode line indicates read-only |
229 | buffers with @samp{%%} or @samp{%*} near the left margin. Read-only | |
230 | buffers are usually made by subsystems such as Dired and Rmail that | |
231 | have special commands to operate on the text; also by visiting a file | |
232 | whose access control says you cannot write it. | |
6bf7aab6 | 233 | |
8f980b27 | 234 | @findex toggle-read-only |
6bf7aab6 | 235 | If you wish to make changes in a read-only buffer, use the command |
8f980b27 AS |
236 | @kbd{C-x C-q} (@code{toggle-read-only}). It makes a read-only buffer |
237 | writable, and makes a writable buffer read-only. This | |
6bf7aab6 DL |
238 | works by setting the variable @code{buffer-read-only}, which has a local |
239 | value in each buffer and makes the buffer read-only if its value is | |
8f980b27 AS |
240 | non-@code{nil}. If you have files under version control, you may find |
241 | it convenient to bind @kbd{C-x C-q} to @code{vc-toggle-read-only} | |
242 | instead. Then, typing @kbd{C-x C-q} not only changes the read-only | |
243 | flag, but it also checks the file in or out. @xref{Version | |
6bf7aab6 DL |
244 | Control}. |
245 | ||
246 | @findex rename-buffer | |
a3053e27 RS |
247 | @kbd{M-x rename-buffer} changes the name of the current buffer. You |
248 | specify the new name as a minibuffer argument; there is no default. | |
249 | If you specify a name that is in use for some other buffer, an error | |
250 | happens and no renaming is done. | |
6bf7aab6 | 251 | |
0e04ec0b | 252 | @findex rename-uniquely |
eddcfd0e RS |
253 | @kbd{M-x rename-uniquely} renames the current buffer to a similar |
254 | name with a numeric suffix added to make it both different and unique. | |
255 | This command does not need an argument. It is useful for creating | |
158a07a8 | 256 | multiple shell buffers: if you rename the @samp{*shell*} buffer, then |
eddcfd0e | 257 | do @kbd{M-x shell} again, it makes a new shell buffer named |
158a07a8 | 258 | @samp{*shell*}; meanwhile, the old shell buffer continues to exist |
eddcfd0e RS |
259 | under its new name. This method is also good for mail buffers, |
260 | compilation buffers, and most Emacs features that create special | |
261 | buffers with particular names. (With some of these features, such as | |
262 | @kbd{M-x compile}, @kbd{M-x grep} an @kbd{M-x info}, you need to | |
263 | switch to some other buffer before using the command, in order for it | |
264 | to make a different buffer.) | |
6bf7aab6 DL |
265 | |
266 | @findex view-buffer | |
267 | @kbd{M-x view-buffer} is much like @kbd{M-x view-file} (@pxref{Misc | |
268 | File Ops}) except that it examines an already existing Emacs buffer. | |
269 | View mode provides commands for scrolling through the buffer | |
270 | conveniently but not for changing it. When you exit View mode with | |
271 | @kbd{q}, that switches back to the buffer (and the position) which was | |
272 | previously displayed in the window. Alternatively, if you exit View | |
273 | mode with @kbd{e}, the buffer and the value of point that resulted from | |
274 | your perusal remain in effect. | |
275 | ||
276 | The commands @kbd{M-x append-to-buffer} and @kbd{M-x insert-buffer} | |
277 | can be used to copy text from one buffer to another. @xref{Accumulating | |
a3053e27 | 278 | Text}. |
6bf7aab6 DL |
279 | |
280 | @node Kill Buffer | |
281 | @section Killing Buffers | |
282 | ||
283 | @cindex killing buffers | |
284 | If you continue an Emacs session for a while, you may accumulate a | |
285 | large number of buffers. You may then find it convenient to @dfn{kill} | |
286 | the buffers you no longer need. On most operating systems, killing a | |
287 | buffer releases its space back to the operating system so that other | |
288 | programs can use it. Here are some commands for killing buffers: | |
289 | ||
6bf7aab6 DL |
290 | @table @kbd |
291 | @item C-x k @var{bufname} @key{RET} | |
292 | Kill buffer @var{bufname} (@code{kill-buffer}). | |
293 | @item M-x kill-some-buffers | |
294 | Offer to kill each buffer, one by one. | |
295 | @end table | |
296 | ||
297 | @findex kill-buffer | |
298 | @findex kill-some-buffers | |
299 | @kindex C-x k | |
300 | ||
301 | @kbd{C-x k} (@code{kill-buffer}) kills one buffer, whose name you | |
ab25a0c7 RS |
302 | specify in the minibuffer. The default, used if you type just |
303 | @key{RET} in the minibuffer, is to kill the current buffer. If you | |
304 | kill the current buffer, another buffer becomes current: one that was | |
305 | current in the recent past but is not displayed in any window now. If | |
306 | you ask to kill a file-visiting buffer that is modified (has unsaved | |
307 | editing), then you must confirm with @kbd{yes} before the buffer is | |
308 | killed. | |
6bf7aab6 DL |
309 | |
310 | The command @kbd{M-x kill-some-buffers} asks about each buffer, one by | |
311 | one. An answer of @kbd{y} means to kill the buffer. Killing the current | |
312 | buffer or a buffer containing unsaved changes selects a new buffer or asks | |
313 | for confirmation just like @code{kill-buffer}. | |
314 | ||
315 | The buffer menu feature (@pxref{Several Buffers}) is also convenient | |
316 | for killing various buffers. | |
317 | ||
318 | @vindex kill-buffer-hook | |
319 | If you want to do something special every time a buffer is killed, you | |
320 | can add hook functions to the hook @code{kill-buffer-hook} (@pxref{Hooks}). | |
321 | ||
322 | @findex clean-buffer-list | |
323 | If you run one Emacs session for a period of days, as many people do, | |
324 | it can fill up with buffers that you used several days ago. The command | |
325 | @kbd{M-x clean-buffer-list} is a convenient way to purge them; it kills | |
326 | all the unmodified buffers that you have not used for a long time. An | |
327 | ordinary buffer is killed if it has not been displayed for three days; | |
328 | however, you can specify certain buffers that should never be killed | |
329 | automatically, and others that should be killed if they have been unused | |
330 | for a mere hour. | |
331 | ||
332 | @cindex Midnight mode | |
333 | @vindex midnight-mode | |
334 | @vindex midnight-hook | |
335 | You can also have this buffer purging done for you, every day at | |
336 | midnight, by enabling Midnight mode. Midnight mode operates each day at | |
337 | midnight; at that time, it runs @code{clean-buffer-list}, or whichever | |
338 | functions you have placed in the normal hook @code{midnight-hook} | |
339 | (@pxref{Hooks}). | |
340 | ||
341 | To enable Midnight mode, use the Customization buffer to set the | |
342 | variable @code{midnight-mode} to @code{t}. @xref{Easy Customization}. | |
343 | ||
344 | @node Several Buffers | |
345 | @section Operating on Several Buffers | |
346 | @cindex buffer menu | |
347 | ||
348 | The @dfn{buffer-menu} facility is like a ``Dired for buffers''; it allows | |
349 | you to request operations on various Emacs buffers by editing an Emacs | |
350 | buffer containing a list of them. You can save buffers, kill them | |
351 | (here called @dfn{deleting} them, for consistency with Dired), or display | |
352 | them. | |
353 | ||
354 | @table @kbd | |
355 | @item M-x buffer-menu | |
356 | Begin editing a buffer listing all Emacs buffers. | |
4081af2f EZ |
357 | @item M-x buffer-menu-other-window. |
358 | Similar, but do it in another window. | |
6bf7aab6 DL |
359 | @end table |
360 | ||
361 | @findex buffer-menu | |
4081af2f EZ |
362 | @findex buffer-menu-other-window |
363 | The command @code{buffer-menu} writes a list of all Emacs | |
364 | buffers@footnote{Buffers which don't visit files and whose names begin | |
38ac48fb EZ |
365 | with a space are omitted: these are used internally by Emacs.} into the |
366 | buffer @samp{*Buffer List*}, and selects that buffer in Buffer Menu | |
7354ca01 RS |
367 | mode. |
368 | ||
369 | The buffer is read-only, and can be | |
38ac48fb EZ |
370 | changed only through the special commands described in this section. |
371 | The usual Emacs cursor motion commands can be used in the @samp{*Buffer | |
372 | List*} buffer. The following commands apply to the buffer described on | |
373 | the current line. | |
6bf7aab6 DL |
374 | |
375 | @table @kbd | |
376 | @item d | |
377 | Request to delete (kill) the buffer, then move down. The request | |
378 | shows as a @samp{D} on the line, before the buffer name. Requested | |
379 | deletions take place when you type the @kbd{x} command. | |
380 | @item C-d | |
381 | Like @kbd{d} but move up afterwards instead of down. | |
382 | @item s | |
383 | Request to save the buffer. The request shows as an @samp{S} on the | |
384 | line. Requested saves take place when you type the @kbd{x} command. | |
385 | You may request both saving and deletion for the same buffer. | |
386 | @item x | |
387 | Perform previously requested deletions and saves. | |
388 | @item u | |
389 | Remove any request made for the current line, and move down. | |
390 | @item @key{DEL} | |
391 | Move to previous line and remove any request made for that line. | |
392 | @end table | |
393 | ||
394 | The @kbd{d}, @kbd{C-d}, @kbd{s} and @kbd{u} commands to add or remove | |
395 | flags also move down (or up) one line. They accept a numeric argument | |
396 | as a repeat count. | |
397 | ||
398 | These commands operate immediately on the buffer listed on the current | |
399 | line: | |
400 | ||
401 | @table @kbd | |
402 | @item ~ | |
403 | Mark the buffer ``unmodified.'' The command @kbd{~} does this | |
404 | immediately when you type it. | |
405 | @item % | |
406 | Toggle the buffer's read-only flag. The command @kbd{%} does | |
407 | this immediately when you type it. | |
408 | @item t | |
409 | Visit the buffer as a tags table. @xref{Select Tags Table}. | |
410 | @end table | |
411 | ||
412 | There are also commands to select another buffer or buffers: | |
413 | ||
414 | @table @kbd | |
415 | @item q | |
416 | Quit the buffer menu---immediately display the most recent formerly | |
417 | visible buffer in its place. | |
418 | @item @key{RET} | |
419 | @itemx f | |
420 | Immediately select this line's buffer in place of the @samp{*Buffer | |
421 | List*} buffer. | |
422 | @item o | |
423 | Immediately select this line's buffer in another window as if by | |
424 | @kbd{C-x 4 b}, leaving @samp{*Buffer List*} visible. | |
425 | @item C-o | |
426 | Immediately display this line's buffer in another window, but don't | |
427 | select the window. | |
428 | @item 1 | |
429 | Immediately select this line's buffer in a full-screen window. | |
430 | @item 2 | |
041aabd8 LT |
431 | Immediately set up two windows, with this line's buffer selected in |
432 | one, and the previously current buffer (aside from the buffer | |
433 | @samp{*Buffer List*}) displayed in the other. | |
6bf7aab6 DL |
434 | @item b |
435 | Bury the buffer listed on this line. | |
436 | @item m | |
437 | Mark this line's buffer to be displayed in another window if you exit | |
438 | with the @kbd{v} command. The request shows as a @samp{>} at the | |
439 | beginning of the line. (A single buffer may not have both a delete | |
440 | request and a display request.) | |
441 | @item v | |
442 | Immediately select this line's buffer, and also display in other windows | |
443 | any buffers previously marked with the @kbd{m} command. If you have not | |
444 | marked any buffers, this command is equivalent to @kbd{1}. | |
445 | @end table | |
446 | ||
7354ca01 RS |
447 | There is also a command that affects the entire buffer list: |
448 | ||
449 | @table @kbd | |
450 | @item T | |
451 | Delete, or reinsert, lines for non-file buffers. This command toggles | |
452 | the inclusion of such buffers in the buffer list. | |
453 | @end table | |
454 | ||
455 | What @code{buffer-menu} actually does is create and switch to a | |
456 | suitable buffer, and turn on Buffer Menu mode in it. Everything else | |
6bf7aab6 DL |
457 | described above is implemented by the special commands provided in |
458 | Buffer Menu mode. One consequence of this is that you can switch from | |
7354ca01 RS |
459 | the @samp{*Buffer List*} buffer to another Emacs buffer, and edit |
460 | there. You can reselect the @samp{*Buffer List*} buffer later, to | |
461 | perform the operations already requested, or you can kill it, or pay | |
462 | no further attention to it. | |
463 | ||
464 | The list in the @samp{*Buffer List*} buffer looks exactly like the | |
465 | buffer list described in @ref{List Buffers}, because they really are | |
466 | the same. The only difference between @code{buffer-menu} and | |
467 | @code{list-buffers} is that @code{buffer-menu} switches to the | |
468 | @samp{*Buffer List*} buffer in the selected window; | |
469 | @code{list-buffers} displays the same buffer in another window. If | |
470 | you run @code{list-buffers} (that is, type @kbd{C-x C-b}) and select | |
471 | the buffer list manually, you can use all of the commands described | |
472 | here. | |
6bf7aab6 | 473 | |
a3053e27 RS |
474 | Normally, the buffer @samp{*Buffer List*} is not updated |
475 | automatically when buffers are created and killed; its contents are | |
476 | just text. If you have created, deleted or renamed buffers, the way | |
477 | to update @samp{*Buffer List*} to show what you have done is to type | |
478 | @kbd{g} (@code{revert-buffer}). You can make this happen regularly | |
479 | every @code{auto-revert-interval} seconds if you enable Auto Revert | |
480 | mode in this buffer, as long as it is not marked modified. Global | |
481 | Auto Revert mode applies to the @samp{*Buffer List*} buffer only if | |
482 | @code{global-auto-revert-non-file-buffers} is non-@code{nil}. | |
bbe9cbb8 | 483 | @iftex |
eca2d6cd | 484 | @inforef{Autorevert,, emacs-xtra}, for details. |
bbe9cbb8 EZ |
485 | @end iftex |
486 | @ifnottex | |
487 | @xref{Autorevert, global-auto-revert-non-file-buffers}, for details. | |
488 | @end ifnottex | |
489 | ||
041aabd8 | 490 | |
4081af2f EZ |
491 | The command @code{buffer-menu-other-window} works the same as |
492 | @code{buffer-menu}, except that it displays the buffers list in | |
493 | another window. | |
494 | ||
6bf7aab6 DL |
495 | @node Indirect Buffers |
496 | @section Indirect Buffers | |
497 | @cindex indirect buffer | |
498 | @cindex base buffer | |
499 | ||
500 | An @dfn{indirect buffer} shares the text of some other buffer, which | |
501 | is called the @dfn{base buffer} of the indirect buffer. In some ways it | |
502 | is the analogue, for buffers, of a symbolic link between files. | |
503 | ||
504 | @table @kbd | |
505 | @findex make-indirect-buffer | |
52ec6cdc | 506 | @item M-x make-indirect-buffer @key{RET} @var{base-buffer} @key{RET} @var{indirect-name} @key{RET} |
6bf7aab6 DL |
507 | Create an indirect buffer named @var{indirect-name} whose base buffer |
508 | is @var{base-buffer}. | |
f16874ce EZ |
509 | @findex clone-indirect-buffer |
510 | @item M-x clone-indirect-buffer @key{RET} | |
511 | Create an indirect buffer that is a twin copy of the current buffer. | |
112c140f | 512 | @item C-x 4 c |
f16874ce EZ |
513 | @kindex C-x 4 c |
514 | @findex clone-indirect-buffer-other-window | |
515 | Create an indirect buffer that is a twin copy of the current buffer, and | |
516 | select it in another window (@code{clone-indirect-buffer-other-window}). | |
6bf7aab6 DL |
517 | @end table |
518 | ||
519 | The text of the indirect buffer is always identical to the text of its | |
520 | base buffer; changes made by editing either one are visible immediately | |
521 | in the other. But in all other respects, the indirect buffer and its | |
522 | base buffer are completely separate. They have different names, | |
523 | different values of point, different narrowing, different markers, | |
524 | different major modes, and different local variables. | |
525 | ||
526 | An indirect buffer cannot visit a file, but its base buffer can. If | |
527 | you try to save the indirect buffer, that actually works by saving the | |
528 | base buffer. Killing the base buffer effectively kills the indirect | |
529 | buffer, but killing an indirect buffer has no effect on its base buffer. | |
530 | ||
531 | One way to use indirect buffers is to display multiple views of an | |
532 | outline. @xref{Outline Views}. | |
b54346bc | 533 | |
564ee37b RS |
534 | A quick and handy way to make an indirect buffer is with the command |
535 | @kbd{M-x clone-indirect-buffer}. It creates and selects an indirect | |
536 | buffer whose base buffer is the current buffer. With a numeric | |
537 | argument, it prompts for the name of the indirect buffer; otherwise it | |
160bde9c LT |
538 | uses the name of the current buffer, with a @samp{<@var{n}>} suffix |
539 | added. @kbd{C-x 4 c} (@code{clone-indirect-buffer-other-window}) | |
540 | works like @kbd{M-x clone-indirect-buffer}, but it selects the new | |
541 | buffer in another window. | |
eddcfd0e RS |
542 | |
543 | The more general way to make an indirect buffer is with the command | |
544 | @kbd{M-x make-indirect-buffer}. It creates an indirect buffer from | |
545 | buffer @var{base-buffer}, under the name @var{indirect-name}. It | |
546 | prompts for both @var{base-buffer} and @var{indirect-name} using the | |
547 | minibuffer. | |
f16874ce | 548 | |
b54346bc DL |
549 | @node Buffer Convenience |
550 | @section Convenience Features and Customization of Buffer Handling | |
551 | ||
85d6c6e7 RS |
552 | This section describes several modes and features that make it more |
553 | convenient to switch between buffers. | |
554 | ||
b54346bc | 555 | @menu |
7354ca01 | 556 | * Uniquify:: Making buffer names unique with directory parts. |
d04efc64 | 557 | * Iswitchb:: Switching between buffers with substrings. |
177c0ea7 | 558 | * Buffer Menus:: Configurable buffer menu. |
b54346bc DL |
559 | @end menu |
560 | ||
561 | @node Uniquify | |
564ee37b | 562 | @subsection Making Buffer Names Unique |
b54346bc | 563 | |
b54346bc DL |
564 | @cindex unique buffer names |
565 | @cindex directories in buffer names | |
564ee37b RS |
566 | When several buffers visit identically-named files, Emacs must give |
567 | the buffers distinct names. The usual method for making buffer names | |
568 | unique adds @samp{<2>}, @samp{<3>}, etc. to the end of the buffer | |
569 | names (all but one of them). | |
570 | ||
571 | @vindex uniquify-buffer-name-style | |
572 | Other methods work by adding parts of each file's directory to the | |
573 | buffer name. To select one, customize the variable | |
574 | @code{uniquify-buffer-name-style} (@pxref{Easy Customization}). | |
575 | ||
576 | For instance, the @code{forward} naming method puts part of the | |
577 | directory name at the beginning of the buffer name; using this method, | |
444246ca | 578 | buffers visiting @file{/u/rms/tmp/Makefile} and |
564ee37b RS |
579 | @file{/usr/projects/zaphod/Makefile} would be named |
580 | @samp{tmp/Makefile} and @samp{zaphod/Makefile}, respectively (instead | |
581 | of @samp{Makefile} and @samp{Makefile<2>}). | |
582 | ||
583 | By contrast, the @code{post-forward} naming method would call the | |
584 | buffers @samp{Makefile|tmp} and @samp{Makefile|zaphod}, and the | |
585 | @code{reverse} naming method would call them @samp{Makefile\tmp} and | |
586 | @samp{Makefile\zaphod}. The nontrivial difference between | |
587 | @code{post-forward} and @code{reverse} occurs when just one directory | |
588 | name is not enough to distinguish two files; then @code{reverse} puts | |
589 | the directory names in reverse order, so that @file{/top/middle/file} | |
590 | becomes @samp{file\middle\top}, while @code{post-forward} puts them in | |
591 | forward order after the file name, as in @samp{file|top/middle}. | |
592 | ||
593 | Which rule to follow for putting the directory names in the buffer | |
594 | name is not very important if you are going to @emph{look} at the | |
595 | buffer names before you type one. But as an experienced user, if you | |
596 | know the rule, you won't have to look. And then you may find that one | |
a3053e27 | 597 | rule or another is easier for you to remember and apply quickly. |
b54346bc | 598 | |
1ea14188 DL |
599 | @node Iswitchb |
600 | @subsection Switching Between Buffers using Substrings | |
601 | ||
602 | @findex iswitchb-mode | |
603 | @cindex Iswitchb mode | |
604 | @cindex mode, Iswitchb | |
605 | @kindex C-x b @r{(Iswitchb mode)} | |
606 | @kindex C-x 4 b @r{(Iswitchb mode)} | |
607 | @kindex C-x 5 b @r{(Iswitchb mode)} | |
608 | @kindex C-x 4 C-o @r{(Iswitchb mode)} | |
609 | ||
564ee37b RS |
610 | Iswitchb global minor mode provides convenient switching between |
611 | buffers using substrings of their names. It replaces the normal | |
612 | definitions of @kbd{C-x b}, @kbd{C-x 4 b}, @kbd{C-x 5 b}, and @kbd{C-x | |
613 | 4 C-o} with alternative commands that are somewhat ``smarter.'' | |
1ea14188 | 614 | |
564ee37b RS |
615 | When one of these commands prompts you for a buffer name, you can |
616 | type in just a substring of the name you want to choose. As you enter | |
617 | the substring, Iswitchb mode continuously displays a list of buffers | |
618 | that match the substring you have typed. | |
1ea14188 | 619 | |
564ee37b RS |
620 | At any time, you can type @key{RET} to select the first buffer in |
621 | the list. So the way to select a particular buffer is to make it the | |
622 | first in the list. There are two ways to do this. You can type more | |
623 | of the buffer name and thus narrow down the list, excluding unwanted | |
624 | buffers above the desired one. Alternatively, you can use @kbd{C-s} | |
625 | and @kbd{C-r} to rotate the list until the desired buffer is first. | |
626 | ||
627 | @key{TAB} while entering the buffer name performs completion on the | |
628 | string you have entered, based on the displayed list of buffers. | |
629 | ||
85d6c6e7 RS |
630 | To enable Iswitchb mode, type @kbd{M-x iswitchb-mode}, or customize |
631 | the variable @code{iswitchb-mode} to @code{t} (@pxref{Easy | |
632 | Customization}). | |
633 | ||
564ee37b RS |
634 | @node Buffer Menus |
635 | @subsection Customizing Buffer Menus | |
b54346bc | 636 | |
d04efc64 | 637 | @findex bs-show |
d04efc64 DL |
638 | @cindex buffer list, customizable |
639 | @table @kbd | |
640 | @item M-x bs-show | |
641 | Make a list of buffers similarly to @kbd{M-x list-buffers} but | |
642 | customizable. | |
d04efc64 DL |
643 | @end table |
644 | ||
564ee37b RS |
645 | @kbd{M-x bs-show} pops up a buffer list similar to the one normally |
646 | displayed by @kbd{C-x C-b} but which you can customize. If you prefer | |
647 | this to the usual buffer list, you can bind this command to @kbd{C-x | |
648 | C-b}. To customize this buffer list, use the @code{bs} Custom group | |
649 | (@pxref{Easy Customization}). | |
1ea14188 DL |
650 | |
651 | @findex msb-mode | |
652 | @cindex mode, MSB | |
653 | @cindex MSB mode | |
654 | @cindex buffer menu | |
655 | @findex mouse-buffer-menu | |
564ee37b RS |
656 | @kindex C-Down-Mouse-1 |
657 | MSB global minor mode (``MSB'' stands for ``mouse select buffer'') | |
658 | provides a different and customizable mouse buffer menu which you may | |
659 | prefer. It replaces the bindings of @code{mouse-buffer-menu}, | |
660 | normally on @kbd{C-Down-Mouse-1}, and the menu bar buffer menu. You | |
661 | can customize the menu in the @code{msb} Custom group. | |
ab5796a9 MB |
662 | |
663 | @ignore | |
664 | arch-tag: 08c43460-f4f4-4b43-9cb5-1ea9ad991695 | |
665 | @end ignore |