@c This is part of the Emacs manual.
-@c Copyright (C) 1985, 86, 87, 93, 94, 95, 97, 2000, 2001
-@c Free Software Foundation, Inc.
+@c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2000, 2001,
+@c 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
@c See file emacs.texi for copying conditions.
@node Buffers, Windows, Files, Top
@chapter Using Multiple Buffers
A buffer's size cannot be larger than some maximum, which is defined
by the largest buffer position representable by the @dfn{Emacs integer}
data type. This is because Emacs tracks buffer positions using that
-data type. For 32-bit machines, the largest buffer size is 128
+data type. For 32-bit machines, the largest buffer size is 256
megabytes.
@menu
* Kill Buffer:: Killing buffers you no longer need.
* Several Buffers:: How to go through the list of all buffers
and operate variously on several of them.
-* Indirect Buffers:: An indirect buffer shares the text of another buffer.
+* Indirect Buffers:: An indirect buffer shares the text of another buffer.
* Buffer Convenience:: Convenience and customization features for
buffer handling.
@end menu
@item C-x 5 b @var{buffer} @key{RET}
Similar, but select @var{buffer} in a separate frame
(@code{switch-to-buffer-other-frame}).
+@item C-x @key{LEFT}
+Select the previous buffer in the list of existing buffers.
+@item C-x @key{RIGHT}
+Select the next buffer in the list of existing buffers.
+@item C-u M-g M-g
+@itemx C-u M-g g
+Read a number @var{n} and move to line @var{n} in the most recently
+selected buffer other than the current buffer.
@end table
@kindex C-x b
@findex switch-to-buffer
To select the buffer named @var{bufname}, type @kbd{C-x b @var{bufname}
@key{RET}}. This runs the command @code{switch-to-buffer} with argument
-@var{bufname}. You can use completion on an abbreviation for the buffer
-name you want (@pxref{Completion}). An empty argument to @kbd{C-x b}
+@var{bufname}. You can use completion to enter the buffer
+name (@pxref{Completion}). An empty argument to @kbd{C-x b}
specifies the buffer that was current most recently among those not
now displayed in any window.
+@kindex C-x @key{LEFT}
+@kindex C-x @key{RIGHT}
+@findex next-buffer
+@findex previous-buffer
+ For conveniently switching between a few buffers, use the commands
+@kbd{C-x @key{LEFT}} and @kbd{C-x @key{RIGHT}}. @kbd{C-x @key{RIGHT}}
+(@code{previous-buffer}) selects the previous buffer (following the order
+of most recent selection in the current frame), while @kbd{C-x @key{LEFT}}
+(@code{next-buffer}) moves through buffers in the reverse direction.
+
@kindex C-x 4 b
@findex switch-to-buffer-other-window
@vindex even-window-heights
@ref{Special Buffer Frames}, for more about these variables. In
addition, if the value of @code{display-buffer-reuse-frames} is
non-@code{nil}, and the buffer you want to switch to is already
-displayed in some frame, Emacs will raise that frame.
+displayed in some frame, Emacs will just raise that frame.
Most buffers are created by visiting files, or by Emacs commands that
want to display some text, but you can also create a buffer explicitly
can also be used to switch to an existing file-visiting buffer.
@xref{Visiting}.
+ @kbd{C-u M-g M-g}, that is @code{goto-line} with a prefix argument
+of just @kbd{C-u}, reads a number @var{n} using the minibuffer,
+selects the most recently selected buffer other than the current
+buffer in another window, and then moves point to the beginning of
+line number @var{n} in that buffer. This is mainly useful in a buffer
+that refers to line numbers in another buffer: if point is on or just
+after a number, @code{goto-line} uses that number as the default for
+@var{n}. Note that prefix arguments other than just @kbd{C-u} behave
+differently. @kbd{C-u 4 M-g M-g} goes to line 4 in the @emph{current}
+buffer, without reading a number from the minibuffer. (Remember that
+@kbd{M-g M-g} without prefix argument reads a number @var{n} and then
+moves to line number @var{n} in the current buffer.)
+
Emacs uses buffer names that start with a space for internal purposes.
It treats these buffers specially in minor ways---for example, by
default they do not record undo information. It is best to avoid using
@cindex listing current buffers
@kindex C-x C-b
@findex list-buffers
- To display a list of all the buffers that exist, type @kbd{C-x C-b}.
-Each line in the list shows one buffer's name, major mode and visited
-file. The buffers are listed in the order that they were current; the
+ To display a list of existing buffers, type @kbd{C-x C-b}. Each
+line in the list shows one buffer's name, major mode and visited file.
+The buffers are listed in the order that they were current; the
buffers that were current most recently come first.
- @samp{*} at the beginning of a line indicates the buffer is ``modified.''
-If several buffers are modified, it may be time to save some with @kbd{C-x s}
-(@pxref{Saving}). @samp{%} indicates a read-only buffer. @samp{.} marks the
-current buffer. Here is an example of a buffer list:@refill
+ @samp{*} in the first field of a line indicates the buffer is
+``modified.'' If several buffers are modified, it may be time to save
+some with @kbd{C-x s} (@pxref{Save Commands}). @samp{%} indicates a
+read-only buffer. @samp{.} marks the current buffer. Here is an
+example of a buffer list:@refill
@smallexample
- MR Buffer Size Mode File
- -- ------ ---- ---- ----
-.* emacs.tex 383402 Texinfo /u2/emacs/man/emacs.tex
- *Help* 1287 Fundamental
- files.el 23076 Emacs-Lisp /u2/emacs/lisp/files.el
- % RMAIL 64042 RMAIL /u/rms/RMAIL
- *% man 747 Dired /u2/emacs/man/
- net.emacs 343885 Fundamental /u/rms/net.emacs
- fileio.c 27691 C /u2/emacs/src/fileio.c
- NEWS 67340 Text /u2/emacs/etc/NEWS
- *scratch* 0 Lisp Interaction
+CRM Buffer Size Mode File
+. * .emacs 3294 Emacs-Lisp ~/.emacs
+ % *Help* 101 Help
+ search.c 86055 C ~/cvs/emacs/src/search.c
+ % src 20959 Dired by name ~/cvs/emacs/src/
+ * *mail* 42 Mail
+ % HELLO 1607 Fundamental ~/cvs/emacs/etc/HELLO
+ % NEWS 481184 Outline ~/cvs/emacs/etc/NEWS
+ *scratch* 191 Lisp Interaction
+ * *Messages* 1554 Fundamental
@end smallexample
@noindent
Note that the buffer @samp{*Help*} was made by a help request; it is
-not visiting any file. The buffer @code{man} was made by Dired on the
-directory @file{/u2/emacs/man/}. You can list only buffers that are
-visiting files by giving the command a prefix; for instance, by typing
+not visiting any file. The buffer @code{src} was made by Dired on the
+directory @file{~/cvs/emacs/src/}. You can list only buffers that are
+visiting files by giving the command a prefix argument, as in
@kbd{C-u C-x C-b}.
-@code{list-buffers} omits buffers whose name begins with a blank,
+ @code{list-buffers} omits buffers whose names begin with a space,
unless they visit files: such buffers are used internally by Emacs.
@need 2000
Control}.
@findex rename-buffer
- @kbd{M-x rename-buffer} changes the name of the current buffer. Specify
-the new name as a minibuffer argument. There is no default. If you
-specify a name that is in use for some other buffer, an error happens and
-no renaming is done.
-
- @kbd{M-x rename-uniquely} renames the current buffer to a similar name
-with a numeric suffix added to make it both different and unique. This
-command does not need an argument. It is useful for creating multiple
-shell buffers: if you rename the @samp{*Shell*} buffer, then do @kbd{M-x
-shell} again, it makes a new shell buffer named @samp{*Shell*};
-meanwhile, the old shell buffer continues to exist under its new name.
-This method is also good for mail buffers, compilation buffers, and most
-Emacs features that create special buffers with particular names.
+ @kbd{M-x rename-buffer} changes the name of the current buffer. You
+specify the new name as a minibuffer argument; there is no default.
+If you specify a name that is in use for some other buffer, an error
+happens and no renaming is done.
+
+@findex rename-uniquely
+ @kbd{M-x rename-uniquely} renames the current buffer to a similar
+name with a numeric suffix added to make it both different and unique.
+This command does not need an argument. It is useful for creating
+multiple shell buffers: if you rename the @samp{*shell*} buffer, then
+do @kbd{M-x shell} again, it makes a new shell buffer named
+@samp{*shell*}; meanwhile, the old shell buffer continues to exist
+under its new name. This method is also good for mail buffers,
+compilation buffers, and most Emacs features that create special
+buffers with particular names. (With some of these features, such as
+@kbd{M-x compile}, @kbd{M-x grep} an @kbd{M-x info}, you need to
+switch to some other buffer before using the command, in order for it
+to make a different buffer.)
@findex view-buffer
@kbd{M-x view-buffer} is much like @kbd{M-x view-file} (@pxref{Misc
The commands @kbd{M-x append-to-buffer} and @kbd{M-x insert-buffer}
can be used to copy text from one buffer to another. @xref{Accumulating
-Text}.@refill
+Text}.
@node Kill Buffer
@section Killing Buffers
buffers@footnote{Buffers which don't visit files and whose names begin
with a space are omitted: these are used internally by Emacs.} into the
buffer @samp{*Buffer List*}, and selects that buffer in Buffer Menu
-mode. The list in the @samp{*Buffer List*} buffer looks exactly as
-described in @ref{List Buffers}. The buffer is read-only, and can be
+mode.
+
+ The buffer is read-only, and can be
changed only through the special commands described in this section.
The usual Emacs cursor motion commands can be used in the @samp{*Buffer
List*} buffer. The following commands apply to the buffer described on
@item 1
Immediately select this line's buffer in a full-screen window.
@item 2
-Immediately set up two windows, with this line's buffer in one, and the
-previously current buffer (aside from the buffer @samp{*Buffer List*})
-in the other.
+Immediately set up two windows, with this line's buffer selected in
+one, and the previously current buffer (aside from the buffer
+@samp{*Buffer List*}) displayed in the other.
@item b
Bury the buffer listed on this line.
@item m
marked any buffers, this command is equivalent to @kbd{1}.
@end table
- All that @code{buffer-menu} does directly is create and switch to a
-suitable buffer, and turn on Buffer Menu mode. Everything else
+ There is also a command that affects the entire buffer list:
+
+@table @kbd
+@item T
+Delete, or reinsert, lines for non-file buffers. This command toggles
+the inclusion of such buffers in the buffer list.
+@end table
+
+ What @code{buffer-menu} actually does is create and switch to a
+suitable buffer, and turn on Buffer Menu mode in it. Everything else
described above is implemented by the special commands provided in
Buffer Menu mode. One consequence of this is that you can switch from
-the @samp{*Buffer List*} buffer to another Emacs buffer, and edit there.
-You can reselect the @samp{*Buffer List*} buffer later, to perform the
-operations already requested, or you can kill it, or pay no further
-attention to it.
-
- The only difference between @code{buffer-menu} and @code{list-buffers}
-is that @code{buffer-menu} switches to the @samp{*Buffer List*} buffer
-in the selected window; @code{list-buffers} displays it in another
-window. If you run @code{list-buffers} (that is, type @kbd{C-x C-b})
-and select the buffer list manually, you can use all of the commands
-described here.
-
- The buffer @samp{*Buffer List*} is not updated automatically when
-buffers are created and killed; its contents are just text. If you have
-created, deleted or renamed buffers, the way to update @samp{*Buffer
-List*} to show what you have done is to type @kbd{g}
-(@code{revert-buffer}) or repeat the @code{buffer-menu} command.
+the @samp{*Buffer List*} buffer to another Emacs buffer, and edit
+there. You can reselect the @samp{*Buffer List*} buffer later, to
+perform the operations already requested, or you can kill it, or pay
+no further attention to it.
+
+ The list in the @samp{*Buffer List*} buffer looks exactly like the
+buffer list described in @ref{List Buffers}, because they really are
+the same. The only difference between @code{buffer-menu} and
+@code{list-buffers} is that @code{buffer-menu} switches to the
+@samp{*Buffer List*} buffer in the selected window;
+@code{list-buffers} displays the same buffer in another window. If
+you run @code{list-buffers} (that is, type @kbd{C-x C-b}) and select
+the buffer list manually, you can use all of the commands described
+here.
+
+ Normally, the buffer @samp{*Buffer List*} is not updated
+automatically when buffers are created and killed; its contents are
+just text. If you have created, deleted or renamed buffers, the way
+to update @samp{*Buffer List*} to show what you have done is to type
+@kbd{g} (@code{revert-buffer}). You can make this happen regularly
+every @code{auto-revert-interval} seconds if you enable Auto Revert
+mode in this buffer, as long as it is not marked modified. Global
+Auto Revert mode applies to the @samp{*Buffer List*} buffer only if
+@code{global-auto-revert-non-file-buffers} is non-@code{nil}.
+@iftex
+@xref{Autorevert,,, emacs-xtra}, for details.
+@end iftex
+@ifnottex
+@xref{Autorevert, global-auto-revert-non-file-buffers}, for details.
+@end ifnottex
+
The command @code{buffer-menu-other-window} works the same as
@code{buffer-menu}, except that it displays the buffers list in
One way to use indirect buffers is to display multiple views of an
outline. @xref{Outline Views}.
-@cindex multiple @samp{*info*} and @samp{*Help*} buffers
A quick and handy way to make an indirect buffer is with the command
@kbd{M-x clone-indirect-buffer}. It creates and selects an indirect
buffer whose base buffer is the current buffer. With a numeric
argument, it prompts for the name of the indirect buffer; otherwise it
-defaults to the name of the current buffer, modifying it by adding a
-@samp{<@var{n}>} prefix if required. @kbd{C-x 4 c}
-(@code{clone-indirect-buffer-other-window}) works like @kbd{M-x
-clone-indirect-buffer}, but it selects the cloned buffer in another
-window. These commands come in handy if you want to create new
-@samp{*info*} or @samp{*Help*} buffers, for example.
-
- The more general way is with the command @kbd{M-x
-make-indirect-buffer}. It creates an indirect buffer from buffer
-@var{base-buffer}, under the name @var{indirect-name}. It prompts for
-both @var{base-buffer} and @var{indirect-name} using the minibuffer.
+uses the name of the current buffer, with a @samp{<@var{n}>} suffix
+added. @kbd{C-x 4 c} (@code{clone-indirect-buffer-other-window})
+works like @kbd{M-x clone-indirect-buffer}, but it selects the new
+buffer in another window.
+
+ The more general way to make an indirect buffer is with the command
+@kbd{M-x make-indirect-buffer}. It creates an indirect buffer from
+buffer @var{base-buffer}, under the name @var{indirect-name}. It
+prompts for both @var{base-buffer} and @var{indirect-name} using the
+minibuffer.
@node Buffer Convenience
@section Convenience Features and Customization of Buffer Handling
convenient to switch between buffers.
@menu
-* Uniquify:: Buffer names can contain directory parts.
+* Uniquify:: Making buffer names unique with directory parts.
* Iswitchb:: Switching between buffers with substrings.
-* Buffer Menus:: Configurable buffer menu.
+* Buffer Menus:: Configurable buffer menu.
@end menu
@node Uniquify
name is not very important if you are going to @emph{look} at the
buffer names before you type one. But as an experienced user, if you
know the rule, you won't have to look. And then you may find that one
-rule or another is easier for you to remember and utilize fast.
+rule or another is easier for you to remember and apply quickly.
@node Iswitchb
@subsection Switching Between Buffers using Substrings
prefer. It replaces the bindings of @code{mouse-buffer-menu},
normally on @kbd{C-Down-Mouse-1}, and the menu bar buffer menu. You
can customize the menu in the @code{msb} Custom group.
+
+@ignore
+ arch-tag: 08c43460-f4f4-4b43-9cb5-1ea9ad991695
+@end ignore