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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.
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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
11file's text. Each time you invoke Dired, a buffer is created to hold the
12directory 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
14command's documentation, that appears in a buffer called @samp{*Help*}.
15
16@cindex selected buffer
17@cindex current buffer
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18 At any time, one and only one buffer is @dfn{current}. It is also
19called 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 21command operates on the current buffer (most commands do).
6bf7aab6 22
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23 When Emacs has multiple windows, each window has its own chosen
24buffer and displays it; at any time, only one of the windows is
ab25a0c7 25selected, and its chosen buffer is the current buffer. Each window's
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26mode line normally displays the name of the window's chosen buffer
27(@pxref{Windows}).
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28
29 Each buffer has a name, which can be of any length, and you can select
30any buffer by giving its name. Most buffers are made by visiting files,
31and their names are derived from the files' names. But you can also create
32an empty buffer with any name you want. A newly started Emacs has a buffer
33named @samp{*scratch*} which can be used for evaluating Lisp expressions in
34Emacs. The distinction between upper and lower case matters in buffer
35names.
36
37 Each buffer records individually what file it is visiting, whether it is
38modified, 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
40particular buffer, meaning its value in that buffer can be different from
41the value in other buffers. @xref{Locals}.
42
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43@cindex buffer size, maximum
44 A buffer's size cannot be larger than some maximum, which is defined
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45by the largest buffer position representable by the @dfn{Emacs integer}
46data type. This is because Emacs tracks buffer positions using that
041aabd8 47data type. For 32-bit machines, the largest buffer size is 256
83692ea3 48megabytes.
dc53c88b 49
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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.
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58* Buffer Convenience:: Convenience and customization features for
59 buffer handling.
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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}
69Select or create a buffer named @var{buffer} (@code{switch-to-buffer}).
70@item C-x 4 b @var{buffer} @key{RET}
71Similar, but select @var{buffer} in another window
72(@code{switch-to-buffer-other-window}).
73@item C-x 5 b @var{buffer} @key{RET}
74Similar, but select @var{buffer} in a separate frame
75(@code{switch-to-buffer-other-frame}).
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76@item C-x @key{LEFT}
77Select the previous buffer in the list of existing buffers.
78@item C-x @key{RIGHT}
79Select the next buffer in the list of existing buffers.
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80@item C-u M-g M-g
81@itemx C-u M-g g
82Read a number @var{n} and move to line @var{n} in the most recently
83selected buffer other than the current buffer.
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84@end table
85
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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
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90@var{bufname}. You can use completion to enter the buffer
91name (@pxref{Completion}). An empty argument to @kbd{C-x b}
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92specifies the buffer that was current most recently among those not
93now displayed in any window.
6bf7aab6 94
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95@kindex C-x @key{LEFT}
96@kindex C-x @key{RIGHT}
97@findex next-buffer
a3700ef7 98@findex previous-buffer
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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}}
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101(@code{previous-buffer}) selects the previous buffer (following the order
102of most recent selection in the current frame), while @kbd{C-x @key{LEFT}}
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103(@code{next-buffer}) moves through buffers in the reverse direction.
104
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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
112causes two vertically adjacent windows to be displayed, the heights of
113those windows are evened out; to countermand that and preserve the
114window 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
121frame.
122
123@vindex display-buffer-reuse-frames
124 You can control how certain buffers are handled by these commands by
125customizing 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
129addition, if the value of @code{display-buffer-reuse-frames} is
130non-@code{nil}, and the buffer you want to switch to is already
a3053e27 131displayed in some frame, Emacs will just raise that frame.
8f7cad1f 132
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133 Most buffers are created by visiting files, or by Emacs commands that
134want to display some text, but you can also create a buffer explicitly
135by typing @kbd{C-x b @var{bufname} @key{RET}}. This makes a new, empty
136buffer that is not visiting any file, and selects it for editing. Such
137buffers are used for making notes to yourself. If you try to save one,
138you are asked for the file name to use. The new buffer's major mode is
139determined by the value of @code{default-major-mode} (@pxref{Major
140Modes}).
141
142 Note that @kbd{C-x C-f}, and any other command for visiting a file,
143can also be used to switch to an existing file-visiting buffer.
144@xref{Visiting}.
145
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146 @kbd{C-u M-g M-g}, that is @code{goto-line} with a prefix argument
147of just @kbd{C-u}, reads a number @var{n} using the minibuffer,
148selects the most recently selected buffer other than the current
149buffer in another window, and then moves point to the beginning of
150line number @var{n} in that buffer. This is mainly useful in a buffer
151that refers to line numbers in another buffer: if point is on or just
152after 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
154differently. @kbd{C-u 4 M-g M-g} goes to line 4 in the @emph{current}
155buffer, 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
157moves to line number @var{n} in the current buffer.)
158
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159 Emacs uses buffer names that start with a space for internal purposes.
160It treats these buffers specially in minor ways---for example, by
161default they do not record undo information. It is best to avoid using
162such buffer names yourself.
163
164@node List Buffers
165@section Listing Existing Buffers
166
167@table @kbd
168@item C-x C-b
169List 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
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175 To display a list of existing buffers, type @kbd{C-x C-b}. Each
176line in the list shows one buffer's name, major mode and visited file.
177The buffers are listed in the order that they were current; the
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178buffers that were current most recently come first.
179
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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
182some with @kbd{C-x s} (@pxref{Save Commands}). @samp{%} indicates a
183read-only buffer. @samp{.} marks the current buffer. Here is an
184example of a buffer list:@refill
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185
186@smallexample
b1a25f96 187CRM Buffer Size Mode File
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188. * .emacs 3294 Emacs-Lisp ~/.emacs
189 % *Help* 101 Help
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190 search.c 86055 C ~/cvs/emacs/src/search.c
191 % src 20959 Dired by name ~/cvs/emacs/src/
6105130d 192 * *mail* 42 Mail
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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
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197@end smallexample
198
199@noindent
564ee37b 200Note that the buffer @samp{*Help*} was made by a help request; it is
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201not visiting any file. The buffer @code{src} was made by Dired on the
202directory @file{~/cvs/emacs/src/}. You can list only buffers that are
a3053e27 203visiting 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,
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207unless they visit files: such buffers are used internally by Emacs.
208
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209@need 2000
210@node Misc Buffer
211@section Miscellaneous Buffer Operations
212
213@table @kbd
214@item C-x C-q
8f980b27 215Toggle read-only status of buffer (@code{toggle-read-only}).
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216@item M-x rename-buffer @key{RET} @var{name} @key{RET}
217Change the name of the current buffer.
218@item M-x rename-uniquely
219Rename the current buffer by adding @samp{<@var{number}>} to the end.
220@item M-x view-buffer @key{RET} @var{buffer} @key{RET}
221Scroll through buffer @var{buffer}.
222@end table
223
224@kindex C-x C-q
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225@vindex buffer-read-only
226@cindex read-only buffer
227 A buffer can be @dfn{read-only}, which means that commands to change
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228its contents are not allowed. The mode line indicates read-only
229buffers with @samp{%%} or @samp{%*} near the left margin. Read-only
230buffers are usually made by subsystems such as Dired and Rmail that
231have special commands to operate on the text; also by visiting a file
232whose 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
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236@kbd{C-x C-q} (@code{toggle-read-only}). It makes a read-only buffer
237writable, and makes a writable buffer read-only. This
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238works by setting the variable @code{buffer-read-only}, which has a local
239value in each buffer and makes the buffer read-only if its value is
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240non-@code{nil}. If you have files under version control, you may find
241it convenient to bind @kbd{C-x C-q} to @code{vc-toggle-read-only}
242instead. Then, typing @kbd{C-x C-q} not only changes the read-only
243flag, but it also checks the file in or out. @xref{Version
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244Control}.
245
246@findex rename-buffer
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247 @kbd{M-x rename-buffer} changes the name of the current buffer. You
248specify the new name as a minibuffer argument; there is no default.
249If you specify a name that is in use for some other buffer, an error
250happens and no renaming is done.
6bf7aab6 251
0e04ec0b 252@findex rename-uniquely
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253 @kbd{M-x rename-uniquely} renames the current buffer to a similar
254name with a numeric suffix added to make it both different and unique.
255This command does not need an argument. It is useful for creating
158a07a8 256multiple shell buffers: if you rename the @samp{*shell*} buffer, then
eddcfd0e 257do @kbd{M-x shell} again, it makes a new shell buffer named
158a07a8 258@samp{*shell*}; meanwhile, the old shell buffer continues to exist
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259under its new name. This method is also good for mail buffers,
260compilation buffers, and most Emacs features that create special
261buffers 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
263switch to some other buffer before using the command, in order for it
264to make a different buffer.)
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265
266@findex view-buffer
267 @kbd{M-x view-buffer} is much like @kbd{M-x view-file} (@pxref{Misc
268File Ops}) except that it examines an already existing Emacs buffer.
269View mode provides commands for scrolling through the buffer
270conveniently 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
272previously displayed in the window. Alternatively, if you exit View
273mode with @kbd{e}, the buffer and the value of point that resulted from
274your perusal remain in effect.
275
276 The commands @kbd{M-x append-to-buffer} and @kbd{M-x insert-buffer}
277can be used to copy text from one buffer to another. @xref{Accumulating
a3053e27 278Text}.
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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
285large number of buffers. You may then find it convenient to @dfn{kill}
286the buffers you no longer need. On most operating systems, killing a
287buffer releases its space back to the operating system so that other
288programs can use it. Here are some commands for killing buffers:
289
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290@table @kbd
291@item C-x k @var{bufname} @key{RET}
292Kill buffer @var{bufname} (@code{kill-buffer}).
293@item M-x kill-some-buffers
294Offer 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
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302specify in the minibuffer. The default, used if you type just
303@key{RET} in the minibuffer, is to kill the current buffer. If you
304kill the current buffer, another buffer becomes current: one that was
305current in the recent past but is not displayed in any window now. If
306you ask to kill a file-visiting buffer that is modified (has unsaved
307editing), then you must confirm with @kbd{yes} before the buffer is
308killed.
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309
310 The command @kbd{M-x kill-some-buffers} asks about each buffer, one by
311one. An answer of @kbd{y} means to kill the buffer. Killing the current
312buffer or a buffer containing unsaved changes selects a new buffer or asks
313for confirmation just like @code{kill-buffer}.
314
315 The buffer menu feature (@pxref{Several Buffers}) is also convenient
316for killing various buffers.
317
318@vindex kill-buffer-hook
319 If you want to do something special every time a buffer is killed, you
320can 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,
324it 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
326all the unmodified buffers that you have not used for a long time. An
327ordinary buffer is killed if it has not been displayed for three days;
328however, you can specify certain buffers that should never be killed
329automatically, and others that should be killed if they have been unused
330for 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
336midnight, by enabling Midnight mode. Midnight mode operates each day at
337midnight; at that time, it runs @code{clean-buffer-list}, or whichever
338functions 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
342variable @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
349you to request operations on various Emacs buffers by editing an Emacs
350buffer containing a list of them. You can save buffers, kill them
351(here called @dfn{deleting} them, for consistency with Dired), or display
352them.
353
354@table @kbd
355@item M-x buffer-menu
356Begin editing a buffer listing all Emacs buffers.
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357@item M-x buffer-menu-other-window.
358Similar, but do it in another window.
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359@end table
360
361@findex buffer-menu
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362@findex buffer-menu-other-window
363 The command @code{buffer-menu} writes a list of all Emacs
364buffers@footnote{Buffers which don't visit files and whose names begin
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365with a space are omitted: these are used internally by Emacs.} into the
366buffer @samp{*Buffer List*}, and selects that buffer in Buffer Menu
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367mode.
368
369 The buffer is read-only, and can be
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370changed only through the special commands described in this section.
371The usual Emacs cursor motion commands can be used in the @samp{*Buffer
372List*} buffer. The following commands apply to the buffer described on
373the current line.
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374
375@table @kbd
376@item d
377Request to delete (kill) the buffer, then move down. The request
378shows as a @samp{D} on the line, before the buffer name. Requested
379deletions take place when you type the @kbd{x} command.
380@item C-d
381Like @kbd{d} but move up afterwards instead of down.
382@item s
383Request to save the buffer. The request shows as an @samp{S} on the
384line. Requested saves take place when you type the @kbd{x} command.
385You may request both saving and deletion for the same buffer.
386@item x
387Perform previously requested deletions and saves.
388@item u
389Remove any request made for the current line, and move down.
390@item @key{DEL}
391Move 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
395flags also move down (or up) one line. They accept a numeric argument
396as a repeat count.
397
398 These commands operate immediately on the buffer listed on the current
399line:
400
401@table @kbd
402@item ~
403Mark the buffer ``unmodified.'' The command @kbd{~} does this
404immediately when you type it.
405@item %
406Toggle the buffer's read-only flag. The command @kbd{%} does
407this immediately when you type it.
408@item t
409Visit 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
416Quit the buffer menu---immediately display the most recent formerly
417visible buffer in its place.
418@item @key{RET}
419@itemx f
420Immediately select this line's buffer in place of the @samp{*Buffer
421List*} buffer.
422@item o
423Immediately 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
426Immediately display this line's buffer in another window, but don't
427select the window.
428@item 1
429Immediately select this line's buffer in a full-screen window.
430@item 2
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431Immediately set up two windows, with this line's buffer selected in
432one, and the previously current buffer (aside from the buffer
433@samp{*Buffer List*}) displayed in the other.
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434@item b
435Bury the buffer listed on this line.
436@item m
437Mark this line's buffer to be displayed in another window if you exit
438with the @kbd{v} command. The request shows as a @samp{>} at the
439beginning of the line. (A single buffer may not have both a delete
440request and a display request.)
441@item v
442Immediately select this line's buffer, and also display in other windows
443any buffers previously marked with the @kbd{m} command. If you have not
444marked any buffers, this command is equivalent to @kbd{1}.
445@end table
446
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447 There is also a command that affects the entire buffer list:
448
449@table @kbd
450@item T
451Delete, or reinsert, lines for non-file buffers. This command toggles
452the 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
456suitable buffer, and turn on Buffer Menu mode in it. Everything else
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457described above is implemented by the special commands provided in
458Buffer Menu mode. One consequence of this is that you can switch from
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459the @samp{*Buffer List*} buffer to another Emacs buffer, and edit
460there. You can reselect the @samp{*Buffer List*} buffer later, to
461perform the operations already requested, or you can kill it, or pay
462no further attention to it.
463
464 The list in the @samp{*Buffer List*} buffer looks exactly like the
465buffer list described in @ref{List Buffers}, because they really are
466the 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
470you run @code{list-buffers} (that is, type @kbd{C-x C-b}) and select
471the buffer list manually, you can use all of the commands described
472here.
6bf7aab6 473
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474 Normally, the buffer @samp{*Buffer List*} is not updated
475automatically when buffers are created and killed; its contents are
476just text. If you have created, deleted or renamed buffers, the way
477to 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
479every @code{auto-revert-interval} seconds if you enable Auto Revert
480mode in this buffer, as long as it is not marked modified. Global
481Auto 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.
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485@end iftex
486@ifnottex
487@xref{Autorevert, global-auto-revert-non-file-buffers}, for details.
488@end ifnottex
489
041aabd8 490
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491 The command @code{buffer-menu-other-window} works the same as
492@code{buffer-menu}, except that it displays the buffers list in
493another window.
494
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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
501is called the @dfn{base buffer} of the indirect buffer. In some ways it
502is 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}
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507Create an indirect buffer named @var{indirect-name} whose base buffer
508is @var{base-buffer}.
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509@findex clone-indirect-buffer
510@item M-x clone-indirect-buffer @key{RET}
511Create an indirect buffer that is a twin copy of the current buffer.
112c140f 512@item C-x 4 c
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513@kindex C-x 4 c
514@findex clone-indirect-buffer-other-window
515Create an indirect buffer that is a twin copy of the current buffer, and
516select it in another window (@code{clone-indirect-buffer-other-window}).
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517@end table
518
519 The text of the indirect buffer is always identical to the text of its
520base buffer; changes made by editing either one are visible immediately
521in the other. But in all other respects, the indirect buffer and its
522base buffer are completely separate. They have different names,
523different values of point, different narrowing, different markers,
524different major modes, and different local variables.
525
526 An indirect buffer cannot visit a file, but its base buffer can. If
527you try to save the indirect buffer, that actually works by saving the
528base buffer. Killing the base buffer effectively kills the indirect
529buffer, 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
532outline. @xref{Outline Views}.
b54346bc 533
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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
536buffer whose base buffer is the current buffer. With a numeric
537argument, it prompts for the name of the indirect buffer; otherwise it
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538uses the name of the current buffer, with a @samp{<@var{n}>} suffix
539added. @kbd{C-x 4 c} (@code{clone-indirect-buffer-other-window})
540works like @kbd{M-x clone-indirect-buffer}, but it selects the new
541buffer in another window.
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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
545buffer @var{base-buffer}, under the name @var{indirect-name}. It
546prompts for both @var{base-buffer} and @var{indirect-name} using the
547minibuffer.
f16874ce 548
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549@node Buffer Convenience
550@section Convenience Features and Customization of Buffer Handling
551
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552 This section describes several modes and features that make it more
553convenient 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.
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559@end menu
560
561@node Uniquify
564ee37b 562@subsection Making Buffer Names Unique
b54346bc 563
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564@cindex unique buffer names
565@cindex directories in buffer names
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566 When several buffers visit identically-named files, Emacs must give
567the buffers distinct names. The usual method for making buffer names
568unique adds @samp{<2>}, @samp{<3>}, etc. to the end of the buffer
569names (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
573buffer 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
577directory name at the beginning of the buffer name; using this method,
444246ca 578buffers visiting @file{/u/rms/tmp/Makefile} and
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579@file{/usr/projects/zaphod/Makefile} would be named
580@samp{tmp/Makefile} and @samp{zaphod/Makefile}, respectively (instead
581of @samp{Makefile} and @samp{Makefile<2>}).
582
583 By contrast, the @code{post-forward} naming method would call the
584buffers @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
588name is not enough to distinguish two files; then @code{reverse} puts
589the directory names in reverse order, so that @file{/top/middle/file}
590becomes @samp{file\middle\top}, while @code{post-forward} puts them in
591forward 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
594name is not very important if you are going to @emph{look} at the
595buffer names before you type one. But as an experienced user, if you
596know the rule, you won't have to look. And then you may find that one
a3053e27 597rule or another is easier for you to remember and apply quickly.
b54346bc 598
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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
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610 Iswitchb global minor mode provides convenient switching between
611buffers using substrings of their names. It replaces the normal
612definitions of @kbd{C-x b}, @kbd{C-x 4 b}, @kbd{C-x 5 b}, and @kbd{C-x
6134 C-o} with alternative commands that are somewhat ``smarter.''
1ea14188 614
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615 When one of these commands prompts you for a buffer name, you can
616type in just a substring of the name you want to choose. As you enter
617the substring, Iswitchb mode continuously displays a list of buffers
618that match the substring you have typed.
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620 At any time, you can type @key{RET} to select the first buffer in
621the list. So the way to select a particular buffer is to make it the
622first in the list. There are two ways to do this. You can type more
623of the buffer name and thus narrow down the list, excluding unwanted
624buffers above the desired one. Alternatively, you can use @kbd{C-s}
625and @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
628string you have entered, based on the displayed list of buffers.
629
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630 To enable Iswitchb mode, type @kbd{M-x iswitchb-mode}, or customize
631the variable @code{iswitchb-mode} to @code{t} (@pxref{Easy
632Customization}).
633
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634@node Buffer Menus
635@subsection Customizing Buffer Menus
b54346bc 636
d04efc64 637@findex bs-show
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638@cindex buffer list, customizable
639@table @kbd
640@item M-x bs-show
641Make a list of buffers similarly to @kbd{M-x list-buffers} but
642customizable.
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643@end table
644
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645 @kbd{M-x bs-show} pops up a buffer list similar to the one normally
646displayed by @kbd{C-x C-b} but which you can customize. If you prefer
647this to the usual buffer list, you can bind this command to @kbd{C-x
648C-b}. To customize this buffer list, use the @code{bs} Custom group
649(@pxref{Easy Customization}).
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650
651@findex msb-mode
652@cindex mode, MSB
653@cindex MSB mode
654@cindex buffer menu
655@findex mouse-buffer-menu
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656@kindex C-Down-Mouse-1
657 MSB global minor mode (``MSB'' stands for ``mouse select buffer'')
658provides a different and customizable mouse buffer menu which you may
659prefer. It replaces the bindings of @code{mouse-buffer-menu},
660normally on @kbd{C-Down-Mouse-1}, and the menu bar buffer menu. You
661can customize the menu in the @code{msb} Custom group.
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662
663@ignore
664 arch-tag: 08c43460-f4f4-4b43-9cb5-1ea9ad991695
665@end ignore