@c This is part of the Emacs manual.
@c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 1999, 2000,
-@c 2001, 2004, 2005 Free Software Foundation, Inc.
+@c 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
@c See file emacs.texi for copying conditions.
@node Files, Buffers, Keyboard Macros, Top
@chapter File Handling
default directory is kept in the variable @code{default-directory},
which has a separate value in every buffer.
- For example, if the default file name is @file{/u/rms/gnu/gnu.tasks} then
-the default directory is @file{/u/rms/gnu/}. If you type just @samp{foo},
-which does not specify a directory, it is short for @file{/u/rms/gnu/foo}.
-@samp{../.login} would stand for @file{/u/rms/.login}. @samp{new/foo}
-would stand for the file name @file{/u/rms/gnu/new/foo}.
-
@findex cd
@findex pwd
The command @kbd{M-x pwd} displays the current buffer's default
directory, and the command @kbd{M-x cd} sets it (to a value read using
the minibuffer). A buffer's default directory changes only when the
@code{cd} command is used. A file-visiting buffer's default directory
-is initialized to the directory of the file that is visited in that buffer. If
-you create a buffer with @kbd{C-x b}, its default directory is copied
-from that of the buffer that was current at the time.
+is initialized to the directory of the file it visits. If you create
+a buffer with @kbd{C-x b}, its default directory is copied from that
+of the buffer that was current at the time.
+
+ For example, if the default file name is @file{/u/rms/gnu/gnu.tasks}
+then the default directory is normally @file{/u/rms/gnu/}. If you
+type just @samp{foo}, which does not specify a directory, it is short
+for @file{/u/rms/gnu/foo}. @samp{../.login} would stand for
+@file{/u/rms/.login}. @samp{new/foo} would stand for the file name
+@file{/u/rms/gnu/new/foo}.
@vindex insert-default-directory
The default directory actually appears in the minibuffer when the
first slash in the double slash; the result is @samp{/x1/rms/foo}.
@xref{Minibuffer File}.
+@cindex home directory shorthand
+ You can use @file{~/} in a file name to mean your home directory,
+or @file{~@var{user-id}/} to mean the home directory of a user whose
+login name is @code{user-id}. (On DOS and Windows systems, where a user
+doesn't have a home directory, Emacs substitutes @file{~/} with the
+value of the environment variable @code{HOME}; see @ref{General
+Variables}.)
+
@cindex environment variables in file names
@cindex expansion of environment variables
@cindex @code{$} in file names
Note that shell commands to set environment variables affect Emacs
only when done before Emacs is started.
-@cindex home directory shorthand
- You can use @file{~/} in a file name to mean your home directory,
-or @file{~@var{user-id}/} to mean the home directory of a user whose
-login name is @code{user-id}. (On DOS and Windows systems, where a user
-doesn't have a home directory, Emacs substitutes @file{~/} with the
-value of the environment variable @code{HOME}; see @ref{General
-Variables}.)
-
To access a file with @samp{$} in its name, if the @samp{$} causes
expansion, type @samp{$$}. This pair is converted to a single
@samp{$} at the same time as variable substitution is performed for a
literal @samp{~} should also be quoted with @samp{/:}.
@findex substitute-in-file-name
- The Lisp function that performs the substitution is called
+ The Lisp function that performs the @samp{$}-substitution is called
@code{substitute-in-file-name}. The substitution is performed only on
file names read as such using the minibuffer.
You can include non-@acronym{ASCII} characters in file names if you set the
variable @code{file-name-coding-system} to a non-@code{nil} value.
-@xref{Specify Coding}.
+@xref{File Name Coding}.
@node Visiting
@section Visiting Files
The changes you make with editing commands are made in the Emacs
buffer. They do not take effect in the file that you visited, or any
-place permanent, until you @dfn{save} the buffer. Saving the buffer
+permanent place, until you @dfn{save} the buffer. Saving the buffer
means that Emacs writes the current contents of the buffer into its
visited file. @xref{Saving}.
@kbd{C-g}. File-name completion ignores certain filenames; for more
about this, see @ref{Completion Options}.
- Your confirmation that @kbd{C-x C-f} has completed successfully is the
-appearance of new text on the screen and a new buffer name in the mode
-line. If the specified file does not exist and could not be created, or
-cannot be read, then you get an error, with an error message displayed
-in the echo area.
+ Your confirmation that @kbd{C-x C-f} has completed successfully is
+the appearance of new text on the screen and a new buffer name in the
+mode line. If the specified file does not exist and you could not
+create it, or exists but you can't read it, then you get an error,
+with an error message displayed in the echo area.
If you visit a file that is already in Emacs, @kbd{C-x C-f} does not make
another copy. It selects the existing buffer containing that file.
-However, before doing so, it checks that the file itself has not changed
-since you visited or saved it last. If the file has changed, a warning
-message is shown. @xref{Interlocking,,Simultaneous Editing}.
+However, before doing so, it checks whether the file itself has changed
+since you visited or saved it last. If the file has changed, Emacs offers
+to reread it.
@vindex large-file-warning-threshold
@cindex maximum buffer size exceeded, error message
saying that the maximum buffer size has been exceeded.
@cindex file selection dialog
- On graphical terminals, there are two additional methods for
+ On graphical displays there are two additional methods for
visiting files. Firstly, when Emacs is built with a suitable GUI
toolkit, commands invoked with the mouse (by clicking on the menu bar
or tool bar) use the toolkit's standard File Selection dialog instead
of prompting for the file name in the minibuffer. On Unix and
GNU/Linux platforms, Emacs does that when built with GTK, LessTif, and
-Motif toolkits; on MS-Windows, the GUI version does that by default.
+Motif toolkits; on MS-Windows and Mac, the GUI version does that by default.
For information on how to customize this, see @ref{Dialog Boxes}.
- Secondly, Emacs supports the ``drag and drop'' protocol on the X
-window system. Dropping a file into an ordinary Emacs window visits
-the file using that window. However, dropping a file into a window
-displaying a Dired buffer moves or copies the file into the displayed
-directory. For details, see @ref{Drag and Drop}, @ref{Misc Dired
-Features}.
+ Secondly, Emacs supports ``drag and drop''; dropping a file into an
+ordinary Emacs window visits the file using that window. However,
+dropping a file into a window displaying a Dired buffer moves or
+copies the file into the displayed directory. For details, see
+@ref{Drag and Drop}, and @ref{Misc Dired Features}.
@cindex creating files
What if you want to create a new file? Just visit it. Emacs displays
@cindex wildcard characters in file names
@vindex find-file-wildcards
- If the file name you specify contains shell-style wildcard characters,
-Emacs visits all the files that match it. Wildcards include @samp{?},
-@samp{*}, and @samp{[@dots{}]} sequences. @xref{Quoted File Names}, for
-information on how to visit a file whose name actually contains wildcard
-characters. You can disable the wildcard feature by customizing
+ If the file name you specify contains shell-style wildcard
+characters, Emacs visits all the files that match it. Wildcards
+include @samp{?}, @samp{*}, and @samp{[@dots{}]} sequences. To enter
+the wild card @samp{?} in a file name in the minibuffer, you need to
+type @kbd{C-q ?}. @xref{Quoted File Names}, for information on how to
+visit a file whose name actually contains wildcard characters. You
+can disable the wildcard feature by customizing
@code{find-file-wildcards}.
If you visit a file that the operating system won't let you modify,
default file name in the buffer, with point just after the directory
part; this is convenient if you made a slight error in typing the name.
- If you find a file which exists but cannot be read, @kbd{C-x C-f}
-signals an error.
-
@kindex C-x 4 f
@findex find-file-other-window
@kbd{C-x 4 f} (@code{find-file-other-window}) is like @kbd{C-x C-f}
@dfn{Saving} a buffer in Emacs means writing its contents back into the file
that was visited in the buffer.
+@menu
+* Save Commands:: Commands for saving files.
+* Backup:: How Emacs saves the old version of your file.
+* Customize Save:: Customizing the saving of files.
+* Interlocking:: How Emacs protects against simultaneous editing
+ of one file by two users.
+* Shadowing: File Shadowing. Copying files to "shadows" automatically.
+* Time Stamps:: Emacs can update time stamps on saved files.
+@end menu
+
+@node Save Commands
+@subsection Commands for Saving Files
+
+ These are the commands that relate to saving and writing files.
+
@table @kbd
@item C-x C-s
Save the current buffer in its visited file on disk (@code{save-buffer}).
Forget that the current buffer has been changed (@code{not-modified}).
With prefix argument (@kbd{C-u}), mark the current buffer as changed.
@item C-x C-w
-Save the current buffer as a specified file name (@code{write-file}).
+Save the current buffer with a specified file name (@code{write-file}).
@item M-x set-visited-file-name
Change the file name under which the current buffer will be saved.
@end table
a different file name, one which is not in use for anything important.
Alternatively, you can cancel all the changes made since the file was
visited or saved, by reading the text from the file again. This is
-called @dfn{reverting}. @xref{Reverting}. You could also undo all the
+called @dfn{reverting}. @xref{Reverting}. (You could also undo all the
changes by repeating the undo command @kbd{C-x u} until you have undone
-all the changes; but reverting is easier.
+all the changes; but reverting is easier.) You can also kill the buffer.
@findex set-visited-file-name
@kbd{M-x set-visited-file-name} alters the name of the file that the
by simultaneous editing and requires your immediate attention.
@xref{Interlocking,, Simultaneous Editing}.
-@vindex require-final-newline
- If the value of the variable @code{require-final-newline} is
-@code{t}, Emacs silently puts a newline at the end of any file that
-doesn't already end in one, every time a file is saved or written. If
-the value is @code{visit}, Emacs adds a newline at the end of any file
-that doesn't have one, just after it visits the file. (This marks the
-buffer as modified, and you can undo it.) If the value is
-@code{visit-save}, that means to add newlines both on visiting and on
-saving. If the value is @code{nil}, Emacs leaves the end of the file
-unchanged; if it's neither @code{nil} nor @code{t}, Emacs asks you
-whether to add a newline. The default is @code{nil}.
-
-@vindex mode-require-final-newline
- Many major modes are designed for specific kinds of files that are
-always supposed to end in newlines. These major modes set the
-variable @code{require-final-newline} according to
-@code{mode-require-final-newline}. By setting the latter variable,
-you can control how these modes handle final newlines.
-
-@menu
-* Backup:: How Emacs saves the old version of your file.
-* Interlocking:: How Emacs protects against simultaneous editing
- of one file by two users.
-* Shadowing: File Shadowing. Copying files to "shadows" automatically.
-* Time Stamps:: Emacs can update time stamps on saved files.
-@end menu
-
@node Backup
@subsection Backup Files
@cindex backup file
are redundant when you store all the previous versions in a version
control system. @xref{General VC Options}.
+ At your option, Emacs can keep either a single backup for each file,
+or make a series of numbered backup files for each file that you edit.
+
@vindex backup-enable-predicate
@vindex temporary-file-directory
@vindex small-temporary-file-directory
for temporary files, specified by @code{temporary-file-directory} or
@code{small-temporary-file-directory}.
- At your option, Emacs can keep either a single backup file or a series of
-numbered backup files for each file that you edit.
-
Emacs makes a backup for a file only the first time the file is saved
from one buffer. No matter how many times you save a file, its backup file
continues to contain the contents from before the file was visited.
newly saved contents if you save again.
@menu
-* Names: Backup Names. How backup files are named;
- choosing single or numbered backup files.
+* One or Many: Numbered Backups. Whether to make one backup file or many.
+* Names: Backup Names. How backup files are named.
* Deletion: Backup Deletion. Emacs deletes excess numbered backups.
* Copying: Backup Copying. Backups can be made by copying or renaming.
@end menu
+@node Numbered Backups
+@subsubsection Numbered Backups
+
+@vindex version-control
+ The choice of single backup file or multiple numbered backup files
+is controlled by the variable @code{version-control}. Its possible
+values are:
+
+@table @code
+@item t
+Make numbered backups.
+@item nil
+Make numbered backups for files that have numbered backups already.
+Otherwise, make single backups.
+@item never
+Never make numbered backups; always make single backups.
+@end table
+
+@noindent
+The usual way to set this variable is globally, through your
+@file{.emacs} file or the customization buffer. However, you can set
+@code{version-control} locally in an individual buffer to control the
+making of backups for that buffer's file. For example, Rmail mode
+locally sets @code{version-control} to @code{never} to make sure that
+there is only one backup for an Rmail file. @xref{Locals}.
+
+@cindex @env{VERSION_CONTROL} environment variable
+ If you set the environment variable @env{VERSION_CONTROL}, to tell
+various GNU utilities what to do with backup files, Emacs also obeys the
+environment variable by setting the Lisp variable @code{version-control}
+accordingly at startup. If the environment variable's value is @samp{t}
+or @samp{numbered}, then @code{version-control} becomes @code{t}; if the
+value is @samp{nil} or @samp{existing}, then @code{version-control}
+becomes @code{nil}; if it is @samp{never} or @samp{simple}, then
+@code{version-control} becomes @code{never}.
+
@node Backup Names
@subsubsection Single or Numbered Backups
- If you choose to have a single backup file (this is the default),
-the backup file's name is normally constructed by appending @samp{~} to the
-file name being edited; thus, the backup file for @file{eval.c} would
-be @file{eval.c~}.
+ When Emacs makes a single backup file, its name is normally
+constructed by appending @samp{~} to the file name being edited; thus,
+the backup file for @file{eval.c} would be @file{eval.c~}.
@vindex make-backup-file-name-function
@vindex backup-directory-alist
@code{backup-directory-alist} applies to numbered backups just as
usual.
-@vindex version-control
- The choice of single backup or numbered backups is controlled by the
-variable @code{version-control}. Its possible values are
-
-@table @code
-@item t
-Make numbered backups.
-@item nil
-Make numbered backups for files that have numbered backups already.
-Otherwise, make single backups.
-@item never
-Never make numbered backups; always make single backups.
-@end table
-
-@noindent
-You can set @code{version-control} locally in an individual buffer to
-control the making of backups for that buffer's file. For example,
-Rmail mode locally sets @code{version-control} to @code{never} to make sure
-that there is only one backup for an Rmail file. @xref{Locals}.
-
-@cindex @env{VERSION_CONTROL} environment variable
- If you set the environment variable @env{VERSION_CONTROL}, to tell
-various GNU utilities what to do with backup files, Emacs also obeys the
-environment variable by setting the Lisp variable @code{version-control}
-accordingly at startup. If the environment variable's value is @samp{t}
-or @samp{numbered}, then @code{version-control} becomes @code{t}; if the
-value is @samp{nil} or @samp{existing}, then @code{version-control}
-becomes @code{nil}; if it is @samp{never} or @samp{simple}, then
-@code{version-control} becomes @code{never}.
-
@node Backup Deletion
@subsubsection Automatic Deletion of Backups
any alternate names for the same file. This has nothing to do with
Emacs---the version control system does it.
+@node Customize Save
+@subsection Customizing Saving of Files
+
+@vindex require-final-newline
+ If the value of the variable @code{require-final-newline} is
+@code{t}, saving or writing a file silently puts a newline at the end
+if there isn't already one there. If the value is @code{visit}, Emacs
+adds a newline at the end of any file that doesn't have one, just
+after it visits the file. (This marks the buffer as modified, and you
+can undo it.) If the value is @code{visit-save}, that means to add
+newlines both on visiting and on saving. If the value is @code{nil},
+Emacs leaves the end of the file unchanged; if it's neither @code{nil}
+nor @code{t}, Emacs asks you whether to add a newline. The default is
+@code{nil}.
+
+@vindex mode-require-final-newline
+ Many major modes are designed for specific kinds of files that are
+always supposed to end in newlines. These major modes set the
+variable @code{require-final-newline} according to
+@code{mode-require-final-newline}. By setting the latter variable,
+you can control how these modes handle final newlines.
+
+@vindex write-region-inhibit-fsync
+ When Emacs saves a file, it invokes the @code{fsync} system call to
+force the data immediately out to disk. This is important for safety
+if the system crashes or in case of power outage. However, it can be
+disruptive on laptops using power saving, because it requires the disk
+to spin up each time you save a file. Setting
+@code{write-region-inhibit-fsync} to a non-@code{nil} value disables
+this synchronization. Be careful---this means increased risk of data
+loss.
+
@node Interlocking
@subsection Protection against Simultaneous Editing
@subsection Shadowing Files
@cindex shadow files
@cindex file shadows
+@findex shadow-initialize
@table @kbd
@item M-x shadow-initialize
@node Time Stamps
@subsection Updating Time Stamps Automatically
-@findex time-stamp
@cindex time stamps
@cindex modification dates
@cindex locale, date format
Time-stamp: " "
@end example
+@findex time-stamp
Then add the hook function @code{time-stamp} to the hook
@code{before-save-hook}; that hook function will automatically update
the time stamp, inserting the current date and time when you save the
You may find it useful to have Emacs revert files automatically when
they change. Three minor modes are available to do this.
- @kbd{M-x global-auto-revert-mode} runs Global Auto-Revert mode,
+ @kbd{M-x global-auto-revert-mode} enables Global Auto-Revert mode,
which periodically checks all file buffers and reverts when the
-corresponding file has changed. @kbd{M-x auto-revert-mode} runs a
-local version, Auto-Revert mode, which applies only to the buffer in
-which it was activated. Auto-Revert mode can be used to ``tail'' a
-file, such as a system log, so that changes made to that file by other
-programs are continuously displayed. To do this, just move the point
-to the end of the buffer, and it will stay there as the file contents
-change. However, if you are sure that the file will only change by
-growing at the end, you can tail the file more efficiently using
-Auto-Revert Tail mode, @kbd{M-x auto-revert-tail-mode}.
+corresponding file has changed. @kbd{M-x auto-revert-mode} enables a
+local version, Auto-Revert mode, which applies only to the current
+buffer.
+
+ You can use Auto-Revert mode to ``tail'' a file such as a system
+log, so that changes made to that file by other programs are
+continuously displayed. To do this, just move the point to the end of
+the buffer, and it will stay there as the file contents change.
+However, if you are sure that the file will only change by growing at
+the end, use Auto-Revert Tail mode instead
+(@code{auto-revert-tail-mode}). It is more efficient for this.
@vindex auto-revert-interval
The variable @code{auto-revert-interval} controls how often to check
for a changed file. Since checking a remote file is too slow, these
modes do not check or revert remote files.
-@xref{VC Mode Line}, for Auto Revert peculiarities in buffers that
+ @xref{VC Mode Line}, for Auto Revert peculiarities in buffers that
visit files under version control.
@node Auto Save
It prevents you from losing more than a limited amount of work if the
system crashes.
- When Emacs determines that it is time for auto-saving, each buffer is
-considered, and is auto-saved if auto-saving is turned on for it and it
-has been changed since the last time it was auto-saved. The message
-@samp{Auto-saving...} is displayed in the echo area during auto-saving,
-if any files are actually auto-saved. Errors occurring during
-auto-saving are caught so that they do not interfere with the execution
-of commands you have been typing.
+ When Emacs determines that it is time for auto-saving, it considers
+each buffer, and each is auto-saved if auto-saving is enabled for it
+and it has been changed since the last time it was auto-saved. The
+message @samp{Auto-saving...} is displayed in the echo area during
+auto-saving, if any files are actually auto-saved. Errors occurring
+during auto-saving are caught so that they do not interfere with the
+execution of commands you have been typing.
@menu
* Files: Auto Save Files. The file where auto-saved changes are
@vindex delete-auto-save-files
A buffer's auto-save file is deleted when you save the buffer in its
-visited file. To inhibit this, set the variable @code{delete-auto-save-files}
-to @code{nil}. Changing the visited file name with @kbd{C-x C-w} or
-@code{set-visited-file-name} renames any auto-save file to go with
-the new visited name.
+visited file. (You can inhibit this by setting the variable
+@code{delete-auto-save-files} to @code{nil}.) Changing the visited
+file name with @kbd{C-x C-w} or @code{set-visited-file-name} renames
+any auto-save file to go with the new visited name.
@node Auto Save Control
@subsection Controlling Auto-Saving
@file{foo} is just an alias. More complex cases occur when symbolic
links point to directories.
- If you visit two names for the same file, normally Emacs makes
-two different buffers, but it warns you about the situation.
-
@vindex find-file-existing-other-name
@vindex find-file-suppress-same-file-warnings
+
Normally, if you visit a file which Emacs is already visiting under
a different name, Emacs displays a message in the echo area and uses
the existing buffer visiting that file. This can happen on systems
-that support symbolic links, or if you use a long file name on a
-system that truncates long file names. You can suppress the message by
-setting the variable @code{find-file-suppress-same-file-warnings} to a
-non-@code{nil} value. You can disable this feature entirely by setting
-the variable @code{find-file-existing-other-name} to @code{nil}: then
-if you visit the same file under two different names, you get a separate
-buffer for each file name.
+that support hard or symbolic links, or if you use a long file name on
+a system that truncates long file names, or on a case-insensitive file
+system. You can suppress the message by setting the variable
+@code{find-file-suppress-same-file-warnings} to a non-@code{nil}
+value. You can disable this feature entirely by setting the variable
+@code{find-file-existing-other-name} to @code{nil}: then if you visit
+the same file under two different names, you get a separate buffer for
+each file name.
@vindex find-file-visit-truename
@cindex truenames of files
terms of capabilities, it is the weakest of the six that VC supports.
VC compensates for certain features missing in SCCS (snapshots, for
example) by implementing them itself, but some other VC features, such
-as multiple branches, are not available with SCCS. You should use
-SCCS only if for some reason you cannot use RCS, or one of the
-higher-level systems such as CVS or GNU Arch.
+as multiple branches, are not available with SCCS. Since SCCS is
+non-free, not respecting its users freedom, you should not use it;
+use its free replacement CSSC instead. But you should use CSSC only
+if for some reason you cannot use RCS, or one of the higher-level
+systems such as CVS or GNU Arch.
In the following, we discuss mainly RCS, SCCS and CVS. Nearly
-everything said about CVS applies to Gnu Arch, Subversion and Meta-CVS
+everything said about CVS applies to GNU Arch, Subversion and Meta-CVS
as well.
@node VC Concepts
When you check in changes, @kbd{C-x v v} first reads a log entry. It
pops up a buffer called @samp{*VC-Log*} for you to enter the log entry.
-Sometimes the @samp{*VC-Log*} buffer contains default text when you enter it,
+ Sometimes the @samp{*VC-Log*} buffer contains default text when you enter it,
typically the last log message entered. If it does, mark and point
are set around the entire contents of the buffer so that it is easy to
kill the contents of the buffer with @kbd{C-w}.
@findex log-edit-insert-changelog
-If you work by writing entries in the @file{ChangeLog}
+ If you work by writing entries in the @file{ChangeLog}
(@pxref{Change Log}) and then commit the change under revision
control, you can generate the Log Edit text from the ChangeLog using
@kbd{C-c C-a} (@kbd{log-edit-insert-changelog}). This looks for
@xref{Change Logs and VC}, for the opposite way of
working---generating ChangeLog entries from the revision control log.
-In the @samp{*VC-Log*} buffer, @kbd{C-c C-f} (@kbd{M-x log-edit-show-files})
+ In the @samp{*VC-Log*} buffer, @kbd{C-c C-f} (@kbd{M-x log-edit-show-files})
shows the list of files to be committed in case you need to check
that. (This can be a list of more than one file if you use VC Dired
mode or PCL-CVS. @xref{VC Dired Mode}, and @ref{Top, , About PCL-CVS,
pcl-cvs, PCL-CVS --- The Emacs Front-End to CVS}.)
-When you have finished editing the log message, type @kbd{C-c C-c} to
+ When you have finished editing the log message, type @kbd{C-c C-c} to
exit the buffer and commit the change.
To abort check-in, just @strong{don't} type @kbd{C-c C-c} in that
own.
@item C-x v =
-Compare the current buffer contents with the latest checked-in version
-of the file.
+Compare the current buffer contents with the master version from which
+you started editing.
@item C-u C-x v = @var{file} @key{RET} @var{oldvers} @key{RET} @var{newvers} @key{RET}
Compare the specified two versions of @var{file}.
It is usually more convenient to compare two versions of the file,
with the command @kbd{C-x v =} (@code{vc-diff}). Plain @kbd{C-x v =}
compares the current buffer contents (saving them in the file if
-necessary) with the last checked-in version of the file. @kbd{C-u C-x
-v =}, with a numeric argument, reads a file name and two version
-numbers, then compares those versions of the specified file. Both
-forms display the output in a special buffer in another window.
+necessary) with the master version from which you started editing the
+file (this is not necessarily the latest version of the file).
+@kbd{C-u C-x v =}, with a numeric argument, reads a file name and two
+version numbers, then compares those versions of the specified file.
+Both forms display the output in a special buffer in another window.
You can specify a checked-in version by its number; an empty input
specifies the current contents of the work file (which may be different
the options in @code{vc-rcs-diff-switches}. The
@samp{vc@dots{}diff-switches} variables are @code{nil} by default.
- Unlike the @kbd{M-x diff} command, @kbd{C-x v =} does not try to
-locate the changes in the old and new versions. This is because
-normally one or both versions do not exist as files when you compare
-them; they exist only in the records of the master file.
-@xref{Comparing Files}, for more information about @kbd{M-x diff}.
+ The buffer produced by @kbd{C-x v =} supports the commands of
+Compilation mode (@pxref{Compilation Mode}), such as @kbd{C-x `} and
+@kbd{C-c C-c}, in both the ``old'' and ``new'' text, and they always
+find the corresponding locations in the current work file. (Older
+versions are not, in general, present as files on your disk.)
@findex vc-annotate
@kindex C-x v g
- For some backends, you can display the file @dfn{annotated} with
+ For some back ends, you can display the file @dfn{annotated} with
per-line version information and using colors to enhance the visual
appearance, with the command @kbd{M-x vc-annotate}.
-It creates a new buffer
-to display file's text, colored to show how old each part is. Text
+It creates a new buffer (the ``annotate buffer'') displaying the
+file's text, with each part colored to show how old it is. Text
colored red is new, blue means old, and intermediate colors indicate
intermediate ages. By default, the time scale is 360 days, so that
everything more than one year old is shown in blue.
stretch factor greater than 1 means the color range spans more than a
year.
-From the annotate buffer, you can use the following keys to browse the
+ From the annotate buffer, you can use the following keys to browse the
annotations of past revisions, view diffs, or view log entries:
-@itemize @bullet
-
-@item
-Pressing @kbd{P} annotates the previous revision. It also takes a
-numeric prefix argument, so for example @kbd{C-u 10 P} would take you
-back 10 revisions.
-
-@item
-Pressing @kbd{N} annotates the next revision. It also takes a numeric
-prefix argument, so for example @kbd{C-u 10 N} would take you forward
-10 revisions.
-
-@item
-Pressing @kbd{J} annotates the revision at line (as denoted by the
-version number on the same line).
-
-@item
-Pressing @kbd{A} annotates the revision previous to line (as denoted
-by the version number on the same line). This is useful to see the
-state the file was in before the change on the current line was made.
-
-@item
-Pressing @kbd{D} shows the diff of the revision at line with its
-previous revision. This is useful to see what actually changed when
-the revision denoted on the current line was committed.
-
-@item
-Pressing @kbd{L} shows the log of the revision at line. This is
-useful to see the author's description of the changes that occurred
-when the revision denoted on the current line was committed.
-
-@item
-Pressing @kbd{W} annotates the workfile (most up to date) version. If
-you used @kbd{P} and @kbd{N} to browse to other revisions, use this
-key to return to the latest version.
-@end itemize
+@table @kbd
+@item P
+Annotate the previous revision, that is to say, the revision before
+the one currently annotated. A numeric prefix argument is a repeat
+count, so @kbd{C-u 10 P} would take you back 10 revisions.
+
+@item N
+Annotate the next revision---the one after the revision currently
+annotated. A numeric prefix argument is a repeat count.
+
+@item J
+Annotate the revision indicated by the current line.
+
+@item A
+Annotate the revision before the one indicated by the current line.
+This is useful to see the state the file was in before the change on
+the current line was made.
+
+@item D
+Display the diff between the current line's revision and the previous
+revision. This is useful to see what the current line's revision
+actually changed in the file.
+
+@item L
+Show the log of the current line's revision. This is useful to see
+the author's description of the changes in the revision on the current
+line.
+
+@item W
+Annotate the workfile version--the one you are editing. If you used
+@kbd{P} and @kbd{N} to browse to other revisions, use this key to
+return to your current version.
+@end table
@node Secondary VC Commands
@subsection The Secondary Commands of VC
If locking is in use, @kbd{C-x v i} leaves the file unlocked and
read-only. Type @kbd{C-x v v} if you wish to start editing it. After
registering a file with CVS, you must subsequently commit the initial
-version by typing @kbd{C-x v v}.
+version by typing @kbd{C-x v v}. Until you do that, the version
+appears as @samp{@@@@} in the mode line.
@vindex vc-default-init-version
@cindex initial version number to register
To view the detailed version control status and history of a file,
type @kbd{C-x v l} (@code{vc-print-log}). It displays the history of
changes to the current file, including the text of the log entries. The
-output appears in a separate window.
+output appears in a separate window. The point is centered at the
+revision of the file that is currently being visited.
+
+ In the change log buffer, you can use the following keys to move
+between the logs of revisions and of files, to view past revisions, and
+to view diffs:
+
+@table @kbd
+@item p
+Move to the previous revision-item in the buffer. (Revision entries in the log
+buffer are usually in reverse-chronological order, so the previous
+revision-item usually corresponds to a newer revision.) A numeric
+prefix argument is a repeat count.
+
+@item n
+Move to the next revision-item (which most often corresponds to the
+previous revision of the file). A numeric prefix argument is a repeat
+count.
+
+@item P
+Move to the log of the previous file, when the logs of multiple files
+are in the log buffer (@pxref{VC Dired Mode}). Otherwise, just move
+to the beginning of the log. A numeric prefix argument is a repeat
+count, so @kbd{C-u 10 P} would move backward 10 files.
+
+@item N
+Move to the log of the next file, when the logs of multiple files are
+in the log buffer (@pxref{VC Dired Mode}). It also takes a numeric
+prefix argument as a repeat count.
+
+@item f
+Visit the revision indicated at the current line, like typing @kbd{C-x
+v ~} and specifying this revision's number (@pxref{Old Versions}).
+
+@item d
+Display the diff (@pxref{Comparing Files}) between the revision
+indicated at the current line and the next earlier revision. This is
+useful to see what actually changed when the revision indicated on the
+current line was committed.
+@end table
@node VC Undo
@subsubsection Undoing Version Control Actions
@table @kbd
@item C-x v u
-Revert the buffer and the file to the last checked-in version.
+Revert the buffer and the file to the version from which you started
+editing the file.
@item C-x v c
Remove the last-entered change from the master for the visited file.
@kindex C-x v u
@findex vc-revert-buffer
If you want to discard your current set of changes and revert to the
-last version checked in, use @kbd{C-x v u} (@code{vc-revert-buffer}).
-This leaves the file unlocked; if locking is in use, you must first lock
-the file again before you change it again. @kbd{C-x v u} requires
-confirmation, unless it sees that you haven't made any changes since the
-last checked-in version.
+version from which you started editing the file, use @kbd{C-x v u}
+(@code{vc-revert-buffer}). This leaves the file unlocked; if locking
+is in use, you must first lock the file again before you change it
+again. @kbd{C-x v u} requires confirmation, unless it sees that you
+haven't made any changes with respect to the master version.
@kbd{C-x v u} is also the command to unlock a file if you lock it and
then decide not to change it.
@findex vc-cancel-version
To cancel a change that you already checked in, use @kbd{C-x v c}
(@code{vc-cancel-version}). This command discards all record of the
-most recent checked-in version. @kbd{C-x v c} also offers to revert
-your work file and buffer to the previous version (the one that precedes
-the version that is deleted).
+most recent checked-in version, but only if your work file corresponds
+to that version---you cannot use @kbd{C-x v c} to cancel a version
+that is not the latest on its branch. @kbd{C-x v c} also offers to
+revert your work file and buffer to the previous version (the one that
+precedes the version that is deleted).
If you answer @kbd{no}, VC keeps your changes in the buffer, and locks
the file. The no-revert option is useful when you have checked in a
have also been checked in to the repository---you need to merge them
with the work file before you can check it in.
+@vindex vc-stay-local
+@vindex vc-cvs-stay-local
+ In the above, if the repository were on a remote machine, VC would
+only contact it when the variable @code{vc-stay-local} (or
+@code{vc-cvs-stay-local}) is nil (@pxref{CVS Options}). This is
+because access to the repository may be slow, or you may be working
+offline and not have access to the repository at all. As a
+consequence, VC would not be able to tell you that @samp{file3.c} is
+in the ``merge'' state; you would learn that only when you try to
+check-in your modified copy of the file, or use a command such as
+@kbd{C-x v m}.
+
+ In practice, this is not a problem because CVS handles this case
+consistently whenever it arises. In VC, you'll simply get prompted to
+merge the remote changes into your work file first. The benefits of
+less network communication usually outweigh the disadvantage of not
+seeing remote changes immediately.
+
@vindex vc-directory-exclusion-list
When VC Dired displays subdirectories (in the ``full'' display mode),
it omits some that should never contain any files under version control.
@cindex named configurations (RCS)
VC's snapshot facilities are modeled on RCS's named-configuration
-support. They use RCS's native facilities for this, so under VC
-snapshots made using RCS are visible even when you bypass VC.
+support. They use RCS's native facilities for this, so
+snapshots made using RCS through VC are visible even when you bypass VC.
+
+ With CVS, Meta-CVS, and Subversion, VC also uses the native
+mechanism provided by that back end to make snapshots and retrieve them
+(@dfn{tags} for CVS and Meta-CVS, @dfn{copies} for Subversion).
@c worded verbosely to avoid overfull hbox.
For SCCS, VC implements snapshots itself. The files it uses contain
name/file/version-number triples. These snapshots are visible only
through VC.
+ There is no support for VC snapshots using GNU Arch yet.
+
A snapshot is a set of checked-in versions. So make sure that all the
files are checked in and not locked when you make a snapshot.
most recent entry in the change log file.
(@code{vc-update-change-log}).
-This command works with RCS or CVS only, not with SCCS.
+This command works with RCS or CVS only, not with any of the other
+back ends.
@item C-u C-x v a
As above, but only find entries for the current buffer's file.
snapshot thus modified may not completely work (@pxref{Snapshot
Caveats}).
+ Some back ends do not provide an explicit rename operation to their
+repositories. After issuing @code{vc-rename-file}, use @kbd{C-x v v}
+on the original and renamed buffers and provide the necessary edit
+log.
+
You cannot use @code{vc-rename-file} on a file that is locked by
someone else.
Sometimes it is convenient to put version identification strings
directly into working files. Certain special strings called
@dfn{version headers} are replaced in each successive version by the
-number of that version.
-
- If you are using RCS, and version headers are present in your working
-files, Emacs can use them to determine the current version and the
-locking state of the files. This is more reliable than referring to the
-master files, which is done when there are no version headers. Note
-that in a multi-branch environment, version headers are necessary to
-make VC behave correctly (@pxref{Multi-User Branching}).
-
- Searching for version headers is controlled by the variable
+number of that version, the name of the user who created it, and other
+relevant information. All of the back ends that VC supports have such
+a mechanism, except GNU Arch.
+
+ VC does not normally use the information contained in these headers.
+The exception is RCS---with RCS, version headers are sometimes more
+reliable than the master file to determine which version of the file
+you are editing. Note that in a multi-branch environment, version
+headers are necessary to make VC behave correctly (@pxref{Multi-User
+Branching}).
+
+ Searching for RCS version headers is controlled by the variable
@code{vc-consult-headers}. If it is non-@code{nil} (the default),
Emacs searches for headers to determine the version number you are
editing. Setting it to @code{nil} disables this feature.
+ Note that although CVS uses the same kind of version headers as RCS
+does, VC never searches for these headers if you are using CVS,
+regardless of the above setting.
+
@kindex C-x v h
@findex vc-insert-headers
You can use the @kbd{C-x v h} command (@code{vc-insert-headers}) to
each string in the list is inserted as a separate header on a line of
its own.
- It is often necessary to use ``superfluous'' backslashes when
+ It may be necessary to use apparently-superfluous backslashes when
writing the strings that you put in this variable. For instance, you
might write @code{"$Id\$"} rather than @code{"$Id@w{$}"}. The extra
backslash prevents the string constant from being interpreted as a
intend to change the file. See the CVS documentation for details on
using the watch feature.
+@vindex vc-stay-local
@vindex vc-cvs-stay-local
@cindex remote repositories (CVS)
When a file's repository is on a remote machine, VC tries to keep
network interactions to a minimum. This is controlled by the variable
-@code{vc-cvs-stay-local}. If it is @code{t} (the default), then VC uses
-only the entry in the local CVS subdirectory to determine the file's
-state (and possibly information returned by previous CVS commands). One
-consequence of this is that when you have modified a file, and somebody
-else has already checked in other changes to the file, you are not
-notified of it until you actually try to commit. (But you can try to
-pick up any recent changes from the repository first, using @kbd{C-x v m
-@key{RET}}, @pxref{Merging}).
+@code{vc-cvs-stay-local}. There is another variable,
+@code{vc-stay-local}, which enables the feature also for other back
+ends that support it, including CVS. In the following, we will talk
+only about @code{vc-cvs-stay-local}, but everything applies to
+@code{vc-stay-local} as well.
-@vindex vc-cvs-global-switches
- The variable @code{vc-cvs-global-switches}, if non-@code{nil},
-should be a string specifying switches to pass to CVS for all CVS
-operations.
+If @code{vc-cvs-stay-local} is @code{t} (the default), then VC uses
+only the entry in the local CVS subdirectory to determine the file's
+state (and possibly information returned by previous CVS commands).
+One consequence of this is that when you have modified a file, and
+somebody else has already checked in other changes to the file, you
+are not notified of it until you actually try to commit. (But you can
+try to pick up any recent changes from the repository first, using
+@kbd{C-x v m @key{RET}}, @pxref{Merging}).
When @code{vc-cvs-stay-local} is @code{t}, VC also makes local
version backups, so that simple diff and revert operations are
that is matched against the repository host name; VC then stays local
only for repositories from hosts that match the pattern.
+@vindex vc-cvs-global-switches
+ You can specify additional command line options to pass to all CVS
+operations in the variable @code{vc-cvs-global-switches}. These
+switches are inserted immediately after the @code{cvs} command, before
+the name of the operation to invoke.
+
@node Directories
@section File Directories
listing} is a list of all the files in a directory. Emacs provides
commands to create and delete directories, and to make directory
listings in brief format (file names only) and verbose format (sizes,
-dates, and authors included). There is also a directory browser called
-Dired; see @ref{Dired}.
+dates, and authors included). Emacs also includes a directory browser
+feature called Dired; see @ref{Dired}.
@table @kbd
@item C-x C-d @var{dir-or-pattern} @key{RET}
@vindex directory-free-space-program
@vindex directory-free-space-args
- Emacs adds information about the amount of free space on the disk
-that contains the directory. To do this, it runs the program
-specified by @code{directory-free-space-program} with arguments
+ In verbose directory listings, Emacs adds information about the
+amount of free space on the disk that contains the directory. To do
+this, it runs the program specified by
+@code{directory-free-space-program} with arguments
@code{directory-free-space-args}.
@node Comparing Files
@code{diff-switches}. The value of @code{diff-switches} should be a
string; the default is @code{"-c"} to specify a context diff.
-@findex diff-goto-source
- After running @kbd{M-x diff}, you can use @kbd{C-x `} to visit
-successive changed locations in the two source files, as in
-Compilation mode (@pxref{Compilation}.) In the @samp{*diff*} buffer,
-you can move to a particular hunk of changes and type @kbd{C-c C-c}
-(@code{diff-goto-source}) to visit the corresponding source location.
-
@findex diff-backup
The command @kbd{M-x diff-backup} compares a specified file with its most
recent backup. If you specify the name of a backup file,
@code{diff-backup} compares it with the source file that it is a backup
of.
+@findex diff-goto-source
+@findex diff-mode
+@cindex Diff mode
+ The @samp{*diff*} buffer uses Diff mode, which enables you to use
+@kbd{C-x `} to visit successive changed locations in the two source
+files, as in Compilation mode (@pxref{Compilation Mode}.) You can
+also move to a particular hunk of changes and type @kbd{C-c C-c}
+(@code{diff-goto-source}) to visit the corresponding source location.
+
+@cindex patches
+ Differences between versions of files are often distributed as
+patches, which are the output from the @command{diff} program. You
+can use Diff mode to operate on a patch by typing @kbd{M-x diff-mode}.
+
@findex compare-windows
The command @kbd{M-x compare-windows} compares the text in the
current window with that in the next window. (For more information
Then the command exits.
If point in the two windows is followed by non-matching text when
-the command starts, it tries heuristically to advance up to matching
-text in the two windows, and then exits. So if you use @kbd{M-x
-compare-windows} repeatedly, each time it either skips one matching
-range or finds the start of another.
+the command starts, @kbd{M-x compare-windows} tries heuristically to
+advance up to matching text in the two windows, and then exits. So if
+you use @kbd{M-x compare-windows} repeatedly, each time it either
+skips one matching range or finds the start of another.
@vindex compare-ignore-case
@vindex compare-ignore-whitespace
@code{compare-windows} normally ignores changes in whitespace, and a
prefix argument turns that off.
-@findex diff-mode
-@cindex diffs
-@cindex patches
-@cindex Diff mode
- Differences between versions of files are often distributed as
-@dfn{patches}, which are the output from @command{diff} or a version
-control system that uses @command{diff}. @kbd{M-x diff-mode} turns on
-Diff mode, a major mode for viewing and editing patches, either as
-``unified diffs'' or ``context diffs.''
-
@cindex Smerge mode
@findex smerge-mode
@cindex failed merges
mode provides commands to resolve conflicts by selecting specific
changes.
- See also @ref{Emerge}, and @ref{Top,,, ediff, The Ediff Manual}, for
-convenient facilities for merging two similar files.
+ @inforef{Emerge,, emacs-xtra} for the Emerge facility, which
+provides a powerful interface for merging files.
@node Misc File Ops
@section Miscellaneous File Operations
@findex write-region
@kbd{M-x write-region} is the inverse of @kbd{M-x insert-file}; it
copies the contents of the region into the specified file. @kbd{M-x
-append-to-file} adds the text of the region to the end of the specified
-file. @xref{Accumulating Text}.
+append-to-file} adds the text of the region to the end of the
+specified file. @xref{Accumulating Text}. The variable
+@code{write-region-inhibit-fsync} applies to these commands, as well
+as saving files; see @ref{Customize Save}.
@findex delete-file
@cindex deletion (of files)
@pindex gzip
Emacs automatically uncompresses compressed files when you visit
-them, and automatically recompress them if you alter them and save
+them, and automatically recompresses them if you alter them and save
them. Emacs recognizes compressed files by their file names. File
names ending in @samp{.gz} indicate a file compressed with
@code{gzip}. Other endings indicate other compression programs.
would in Dired, and visit the subfiles contained in the archive.
However, not all Dired commands are available in Tar mode.
- If you enable Auto Compression mode (@pxref{Compressed Files}), then
+ If Auto Compression mode is enabled (@pxref{Compressed Files}), then
Tar mode is used also for compressed archives---files with extensions
@samp{.tgz}, @code{.tar.Z} and @code{.tar.gz}.
The keys @kbd{e}, @kbd{f} and @key{RET} all extract a component file
-into its own buffer. You can edit it there and when you save the buffer
-the edited version will replace the version in the Tar buffer. @kbd{v}
-extracts a file into a buffer in View mode. @kbd{o} extracts the file
-and displays it in another window, so you could edit the file and
-operate on the archive simultaneously. @kbd{d} marks a file for
+into its own buffer. You can edit it there, and if you save the
+buffer, the edited version will replace the version in the Tar buffer.
+@kbd{v} extracts a file into a buffer in View mode. @kbd{o} extracts
+the file and displays it in another window, so you could edit the file
+and operate on the archive simultaneously. @kbd{d} marks a file for
deletion when you later use @kbd{x}, and @kbd{u} unmarks a file, as in
Dired. @kbd{C} copies a file from the archive to disk and @kbd{R}
-renames a file. @kbd{g} reverts the buffer from the archive on disk.
+renames a file within the archive. @kbd{g} reverts the buffer from
+the archive on disk.
The keys @kbd{M}, @kbd{G}, and @kbd{O} change the file's permission
bits, group, and owner, respectively.
Normally, if you do not specify a user name in a remote file name,
that means to use your own user name. But if you set the variable
@code{ange-ftp-default-user} to a string, that string is used instead.
-(The Emacs package that implements FTP file access is called
-@code{ange-ftp}.)
@cindex anonymous FTP
@vindex ange-ftp-generate-anonymous-password
@code{ange-ftp-generate-anonymous-password} controls what happens: if
the value of this variable is a string, then that string is used as
the password; if non-@code{nil} (the default), then the value of
-@code{user-mail-address} is used; if @code{nil}, the user is prompted
-for a password as normal.
+@code{user-mail-address} is used; if @code{nil}, then Emacs prompts
+you for a password as usual.
@cindex firewall, and accessing remote files
@cindex gateway, and remote file access with @code{ange-ftp}
When typing a file name in the minibuffer, @kbd{C-@key{tab}}
(@code{file-cache-minibuffer-complete}) completes it using the file
name cache. If you repeat @kbd{C-@key{tab}}, that cycles through the
-possible completions of what you had originally typed. Note that the
-@kbd{C-@key{tab}} character cannot be typed on most text-only
-terminals.
+possible completions of what you had originally typed. (However, note
+that the @kbd{C-@key{tab}} character cannot be typed on most text-only
+terminals.)
The file name cache does not fill up automatically. Instead, you
load file names into the cache using these commands:
Clear the cache; that is, remove all file names from it.
@end table
+ The file name cache is not persistent: it is kept and maintained
+only for the duration of the Emacs session. You can view the contents
+of the cache with the @code{file-cache-display} command.
+
@node File Conveniences
@section Convenience Features for Finding Files
@findex filesets-add-buffer
@findex filesets-remove-buffer
- The simplest way to define filesets is by adding files to them one
+ The simplest way to define a fileset is by adding files to it one
at a time. To add a file to fileset @var{name}, visit the file and
type @kbd{M-x filesets-add-buffer @kbd{RET} @var{name} @kbd{RET}}. If
there is no fileset @var{name}, this creates a new one, which