@c This is part of the Emacs manual.
-@c Copyright (C) 1985-1987, 1993-1995, 1997, 1999-2012
-@c Free Software Foundation, Inc.
+@c Copyright (C) 1985-1987, 1993-1995, 1997, 1999-2013 Free Software
+@c Foundation, Inc.
@c See file emacs.texi for copying conditions.
-@node Files, Buffers, Keyboard Macros, Top
+@node Files
@chapter File Handling
@cindex files
* Misc File Ops:: Other things you can do on files.
* Compressed Files:: Accessing compressed files.
* File Archives:: Operating on tar, zip, jar etc. archive files.
-* Remote Files:: Accessing files on other sites.
+* Remote Files:: Accessing files on other machines.
* Quoted File Names:: Quoting special characters in file names.
* File Name Cache:: Completion against a list of files you often use.
* File Conveniences:: Convenience Features for Finding Files.
inhibit this insertion by changing the variable
@code{insert-default-directory} to @code{nil} (@pxref{Minibuffer
File}). Regardless, Emacs always assumes that any relative file name
-is relative to the default directory, e.g. entering a file name
+is relative to the default directory, e.g., entering a file name
without a directory specifies a file in the default directory.
@findex cd
When typing a file name into the minibuffer, you can make use of a
couple of shortcuts: a double slash is interpreted as ``ignore
-everything before the second slash in the pair,'' and @samp{~/} is
+everything before the second slash in the pair'', and @samp{~/} is
interpreted as your home directory. @xref{Minibuffer File}.
@cindex environment variables in file names
or that is marked read-only, Emacs makes the buffer read-only too, so
that you won't go ahead and make changes that you'll have trouble
saving afterward. You can make the buffer writable with @kbd{C-x C-q}
-(@code{toggle-read-only}). @xref{Misc Buffer}.
+(@code{read-only-mode}). @xref{Misc Buffer}.
@kindex C-x C-r
@findex find-file-read-only
Each time you visit a file, Emacs automatically scans its contents
to detect what character encoding and end-of-line convention it uses,
-and converts these to Emacs' internal encoding and end-of-line
+and converts these to Emacs's internal encoding and end-of-line
convention within the buffer. When you save the buffer, Emacs
performs the inverse conversion, writing the file to disk with its
original encoding and end-of-line convention. @xref{Coding Systems}.
@cindex locking files
When you make the first modification in an Emacs buffer that is
visiting a file, Emacs records that the file is @dfn{locked} by you.
-(It does this by creating a specially-named symbolic link in the same
-directory.) Emacs removes the lock when you save the changes. The
-idea is that the file is locked whenever an Emacs buffer visiting it
-has unsaved changes.
+(It does this by creating a specially-named symbolic link or regular
+file with special contents in the same directory.) Emacs removes the
+lock when you save the changes. The idea is that the file is locked
+whenever an Emacs buffer visiting it has unsaved changes.
+
+@vindex create-lockfiles
+ You can prevent the creation of lock files by setting the variable
+@code{create-lockfiles} to @code{nil}. @strong{Caution:} by
+doing so you will lose the benefits that this feature provides.
@cindex collision
If you begin to modify the buffer while the visited file is locked by
multiple names, Emacs does not prevent two users from editing it
simultaneously under different names.
- A lock file cannot be written in some circumstances, e.g. if Emacs
-lacks the system permissions or the system does not support symbolic
-links. In these cases, Emacs can still detect the collision when you
-try to save a file, by checking the file's last-modification date. If
-the file has changed since the last time Emacs visited or saved it,
-that implies that changes have been made in some other way, and will
-be lost if Emacs proceeds with saving. Emacs then displays a warning
-message and asks for confirmation before saving; answer @kbd{yes} to
-save, and @kbd{no} or @kbd{C-g} cancel the save.
+ A lock file cannot be written in some circumstances, e.g., if Emacs
+lacks the system permissions or cannot create lock files for some
+other reason. In these cases, Emacs can still detect the collision
+when you try to save a file, by checking the file's last-modification
+date. If the file has changed since the last time Emacs visited or
+saved it, that implies that changes have been made in some other way,
+and will be lost if Emacs proceeds with saving. Emacs then displays a
+warning message and asks for confirmation before saving; answer
+@kbd{yes} to save, and @kbd{no} or @kbd{C-g} cancel the save.
If you are notified that simultaneous editing has already taken
place, one way to compare the buffer to its file is the @kbd{M-x
when they are auto-saved, the auto-save file name is made by appending
@samp{#} to the front and rear of buffer name, then
adding digits and letters at the end for uniqueness. For
-example, the @samp{*mail*} buffer in which you compose messages to be
+example, the @file{*mail*} buffer in which you compose messages to be
sent might be auto-saved in a file named @file{#*mail*#704juu}. Auto-save file
names are made this way unless you reprogram parts of Emacs to do
something different (the functions @code{make-auto-save-file-name} and
this---saving them---updates the files themselves.
@vindex auto-save-list-file-prefix
- Emacs records information about interrupted sessions for later
-recovery in files named @file{.saves-@var{pid}-@var{hostname}} in the
-directory @file{~/.emacs.d/auto-save-list/}. This directory is
-determined by the variable @code{auto-save-list-file-prefix}. If you
-set @code{auto-save-list-file-prefix} to @code{nil}, sessions are not
+ Emacs records information about interrupted sessions in files named
+@file{.saves-@var{pid}-@var{hostname}} in the directory
+@file{~/.emacs.d/auto-save-list/}. This directory is determined by
+the variable @code{auto-save-list-file-prefix}. If you set
+@code{auto-save-list-file-prefix} to @code{nil}, sessions are not
recorded for recovery.
@node File Aliases
@vindex diff-switches
The command @kbd{M-x diff} prompts for two file names, using the
minibuffer, and displays the differences between the two files in a
-buffer named @samp{*diff*}. This works by running the @command{diff}
+buffer named @file{*diff*}. This works by running the @command{diff}
program, using options taken from the variable @code{diff-switches}.
The value of @code{diff-switches} should be a string; the default is
@code{"-c"} to specify a context diff. @xref{Top,, Diff, diff,
You can edit a Diff mode buffer like any other buffer. (If it is
read-only, you need to make it writable first. @xref{Misc Buffer}.)
Whenever you change a hunk, Diff mode attempts to automatically
-correct the line numbers in the hunk headers, to ensure that the diff
+correct the line numbers in the hunk headers, to ensure that the patch
remains ``correct''. To disable automatic line number correction,
change the variable @code{diff-update-on-the-fly} to @code{nil}.
- Diff mode treats each hunk as an ``error message,'' similar to
+ Diff mode treats each hunk as an ``error message'', similar to
Compilation mode. Thus, you can use commands such as @kbd{C-x '} to
visit the corresponding source locations. @xref{Compilation Mode}.
operates on behalf of the current hunk's file, but gets the function
name from the patch itself. This is useful for making log entries for
functions that are deleted by the patch.
-
-@item M-x diff-show-trailing-whitespaces RET
-@findex diff-show-trailing-whitespaces
-Highlight trailing whitespace characters, except for those used by the
-patch syntax (@pxref{Useless Whitespace}).
@end table
+@c Trailing whitespace is NOT shown by default.
+@c Emacs's dir-locals file enables this (for some reason).
+@cindex trailing whitespace, in patches
+@findex diff-delete-trailing-whitespace
+ Patches sometimes include trailing whitespace on modified lines, as
+an unintentional and undesired change. There are two ways to deal
+with this problem. Firstly, if you enable Whitespace mode in a Diff
+buffer (@pxref{Useless Whitespace}), it automatically highlights
+trailing whitespace in modified lines. Secondly, you can use the
+command @kbd{M-x diff-delete-trailing-whitespace}, which searches for
+trailing whitespace in the lines modified by the patch, and removes
+that whitespace in both the patch and the patched source file(s).
+This command does not save the modifications that it makes, so you can
+decide whether to save the changes (the list of modified files is
+displayed in the echo area). With a prefix argument, it tries to
+modify the original source files rather than the patched source files.
+
@node Misc File Ops
@section Miscellaneous File Operations
@var{target} at the time the opening is done, or will get an error if
the name @var{target} is nonexistent at that time. This command does
not expand the argument @var{target}, so that it allows you to specify
-a relative name as the target of the link. Not all systems support
-symbolic links; on systems that don't support them, this command is
-not defined.
+a relative name as the target of the link. On MS-Windows, this
+command works only on MS Windows Vista and later.
@kindex C-x i
@findex insert-file
(@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. (However, note
-that the @kbd{C-@key{tab}} character cannot be typed on most text-only
+that the @kbd{C-@key{tab}} character cannot be typed on most text
terminals.)
The file name cache does not fill up automatically. Instead, you
subdirectories to the file name cache, using @command{locate} to find
them all.
@item M-x file-cache-add-directory-list @key{RET} @var{variable} @key{RET}
-Add each file name in each directory listed in @var{variable}
-to the file name cache. @var{variable} should be a Lisp variable
-such as @code{load-path} or @code{exec-path}, whose value is a list
-of directory names.
+Add each file name in each directory listed in @var{variable} to the
+file name cache. @var{variable} should be a Lisp variable whose value
+is a list of directory names, like @code{load-path}.
@item M-x file-cache-clear-cache @key{RET}
Clear the cache; that is, remove all file names from it.
@end table
@findex image-mode
@findex image-toggle-display
+@findex image-toggle-animation
@cindex images, viewing
- Visiting image files automatically selects Image mode. This major
-mode allows you to toggle between displaying the file as an image in
-the Emacs buffer, and displaying its underlying text representation,
-using the command @kbd{C-c C-c} (@code{image-toggle-display}). This
-works only when Emacs can display the specific image type. If the
-displayed image is wider or taller than the frame, the usual point
-motion keys (@kbd{C-f}, @kbd{C-p}, and so forth) cause different parts
-of the image to be displayed.
+@cindex image animation
+@cindex animated images
+ Visiting image files automatically selects Image mode. In this
+major mode, you can type @kbd{C-c C-c} (@code{image-toggle-display})
+to toggle between displaying the file as an image in the Emacs buffer,
+and displaying its underlying text (or raw byte) representation.
+Displaying the file as an image works only if Emacs is compiled with
+support for displaying such images. If the displayed image is wider
+or taller than the frame, the usual point motion keys (@kbd{C-f},
+@kbd{C-p}, and so forth) cause different parts of the image to be
+displayed. If the image can be animated, the command @kbd{RET}
+(@code{image-toggle-animation}) starts or stops the animation.
+Animation plays once, unless the option @code{image-animate-loop} is
+non-@code{nil}.
+
+@cindex ImageMagick support
+@vindex imagemagick-enabled-types
+@vindex imagemagick-types-inhibit
+ If Emacs was compiled with support for the ImageMagick library, it
+can use ImageMagick to render a wide variety of images. The variable
+@code{imagemagick-enabled-types} lists the image types that Emacs may
+render using ImageMagick; each element in the list should be an
+internal ImageMagick name for an image type, as a symbol or an
+equivalent string (e.g., @code{BMP} for @file{.bmp} images). To
+enable ImageMagick for all possible image types, change
+@code{imagemagick-enabled-types} to @code{t}. The variable
+@code{imagemagick-types-inhibit} lists the image types which should
+never be rendered using ImageMagick, regardless of the value of
+@code{imagemagick-enabled-types} (the default list includes types like
+@code{C} and @code{HTML}, which ImageMagick can render as an ``image''
+but Emacs should not). To disable ImageMagick entirely, change
+@code{imagemagick-types-inhibit} to @code{t}.
@findex thumbs-mode
@findex mode, thumbs
- See also the Image-Dired package (@pxref{Image-Dired}) for viewing
-images as thumbnails.
+ The Image-Dired package can also be used to view images as
+thumbnails. @xref{Image-Dired}.
@node Filesets
@section Filesets
@findex filesets-add-buffer
@findex filesets-remove-buffer
- 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
+ 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
-initially creates only the current file. The command @kbd{M-x
+initially contains only the current file. The command @kbd{M-x
filesets-remove-buffer} removes the current file from a fileset.
You can also edit the list of filesets directly, with @kbd{M-x
filesets-edit} (or by choosing @samp{Edit Filesets} from the
@samp{Filesets} menu). The editing is performed in a Customize buffer
-(@pxref{Easy Customization}). Filesets need not be a simple list of
-files---you can also define filesets using regular expression matching
-file names. Some examples of these more complicated filesets are
-shown in the Customize buffer. Remember to select @samp{Save for
+(@pxref{Easy Customization}). Normally, a fileset is a simple list of
+files, but you can also define a fileset as a regular expression
+matching file names. Some examples of these more complicated filesets
+are shown in the Customize buffer. Remember to select @samp{Save for
future sessions} if you want to use the same filesets in future Emacs
sessions.