Merge from emacs-23

[gnu-emacs] / doc / emacs / dired.texi

@c This is part of the Emacs manual.
@c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2000, 2001,
@c   2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
@c   Free Software Foundation, Inc.
@c See file emacs.texi for copying conditions.
@node Dired, Calendar/Diary, Rmail, Top
@chapter Dired, the Directory Editor
@c This node is referenced in the tutorial.  When renaming or deleting
@c it, the tutorial needs to be adjusted.
@cindex Dired
@cindex file management

  Dired makes an Emacs buffer containing a listing of a directory, and
optionally some of its subdirectories as well.  You can use the normal
Emacs commands to move around in this buffer, and special Dired
commands to operate on the listed files.

    The Dired buffer is ``read-only,'' and inserting text in it is not
allowed.  Ordinary printing characters such as @kbd{d} and @kbd{x} are
redefined for special Dired commands.  Some Dired commands @dfn{mark}
or @dfn{flag} the @dfn{current file} (that is, the file on the current
line); other commands operate on the marked files or on the flagged
files.  You first mark certain files in order to operate on all of
them with one command.

  The Dired-X package provides various extra features for Dired mode.
@xref{Top, Dired-X,,dired-x, Dired Extra Version 2 User's Manual}.

  You can also view a list of files in a directory with @kbd{C-x C-d}
(@code{list-directory}).  Unlike Dired, this command does not allow
you to operate on the listed files.  @xref{Directories}.

@menu
* Enter: Dired Enter.         How to invoke Dired.
* Navigation: Dired Navigation.   Special motion commands in the Dired buffer.
* Deletion: Dired Deletion.   Deleting files with Dired.
* Flagging Many Files::       Flagging files based on their names.
* Visit: Dired Visiting.      Other file operations through Dired.
* Marks vs Flags::            Flagging for deletion vs marking.
* Operating on Files::        How to copy, rename, print, compress, etc.
                                either one file or several files.
* Shell Commands in Dired::   Running a shell command on the marked files.
* Transforming File Names::   Using patterns to rename multiple files.
* Comparison in Dired::       Running `diff' by way of Dired.
* Subdirectories in Dired::   Adding subdirectories to the Dired buffer.
@ifnottex
* Subdir Switches::           Subdirectory switches in Dired.
@end ifnottex
* Subdirectory Motion::       Moving across subdirectories, and up and down.
* Hiding Subdirectories::     Making subdirectories visible or invisible.
* Updating: Dired Updating.   Discarding lines for files of no interest.
* Find: Dired and Find.       Using `find' to choose the files for Dired.
* Wdired::                    Operating on files by editing the Dired buffer.
* Image-Dired::               Viewing image thumbnails in Dired.
* Misc: Misc Dired Features.  Various other features.
@end menu

@node Dired Enter
@section Entering Dired

@findex dired
@kindex C-x d
@vindex dired-listing-switches
  To invoke Dired, type @kbd{C-x d} (@code{dired}).  This reads a
directory name using the minibuffer, and opens a @dfn{Dired buffer}
listing the files in that directory.  You can also supply a wildcard
file name pattern as the minibuffer argument, in which case the Dired
buffer lists all files matching that pattern.  The usual history and
completion commands can be used in the minibuffer; in particular,
@kbd{M-n} puts the name of the visited file (if any) in the minibuffer
(@pxref{Minibuffer History}).

  You can also invoke Dired by giving @kbd{C-x C-f} (@code{find-file})
a directory name.

  The variable @code{dired-listing-switches} specifies the options to
give to @code{ls} for listing the directory; this string @emph{must}
contain @samp{-l}.  If you use a numeric prefix argument with the
@code{dired} command, you can specify the @code{ls} switches with the
minibuffer before you enter the directory specification.  No matter
how they are specified, the @code{ls} switches can include short
options (that is, single characters) requiring no arguments, and long
options (starting with @samp{--}) whose arguments are specified with
@samp{=}.

  On MS-Windows and MS-DOS systems, Emacs @emph{emulates} @code{ls};
see @ref{ls in Lisp}, for options and peculiarities of that emulation.

@findex dired-other-window
@kindex C-x 4 d
@findex dired-other-frame
@kindex C-x 5 d
  To display the Dired buffer in another window rather than in the
selected window, use @kbd{C-x 4 d} (@code{dired-other-window}) instead
of @kbd{C-x d}.  @kbd{C-x 5 d} (@code{dired-other-frame}) uses a
separate frame to display the Dired buffer.

@node Dired Navigation
@section Navigation in the Dired Buffer

@kindex C-n @r{(Dired)}
@kindex C-p @r{(Dired)}
  All the usual Emacs cursor motion commands are available in Dired
buffers.  The keys @kbd{C-n} and @kbd{C-p} are redefined to put the
cursor at the beginning of the file name on the line, rather than at
the beginning of the line.

@kindex SPC @r{(Dired)}
  For extra convenience, @key{SPC} and @kbd{n} in Dired are equivalent
to @kbd{C-n}.  @kbd{p} is equivalent to @kbd{C-p}.  (Moving by lines
is so common in Dired that it deserves to be easy to type.)  @key{DEL}
(move up and unflag) is also often useful simply for moving up
(@pxref{Dired Deletion}).

@findex dired-goto-file
@kindex j @r{(Dired)}
  @kbd{j} (@code{dired-goto-file}) prompts for a file name using the
minibuffer, and moves point to the line in the Dired buffer describing
that file.

@cindex searching Dired buffers
@vindex dired-isearch-filenames
  @kbd{M-s f C-s} (@code{dired-isearch-filenames}) performs a forward
incremental search in the Dired buffer, looking for matches only
amongst the file names and ignoring the rest of the text in the
buffer.  @kbd{M-s f M-C-s} (@code{dired-isearch-filenames-regexp})
does the same, using a regular expression search.  If you change the
variable @code{dired-isearch-filenames} to @code{t}, then the
usual search commands also limit themselves to the file names; for
instance, @kbd{C-s} behaves like @kbd{M-s f C-s}.  If the value is
@code{dwim}, then search commands match the file names only when point
was on a file name initially.  @xref{Search}, for information about
incremental search.

  Some additional navigation commands are available when the Dired
buffer includes several directories.  @xref{Subdirectory Motion}.

@node Dired Deletion
@section Deleting Files with Dired
@cindex flagging files (in Dired)
@cindex deleting files (in Dired)

  One of the most frequent uses of Dired is to first @dfn{flag} files for
deletion, then delete the files that were flagged.

@table @kbd
@item d
Flag this file for deletion.
@item u
Remove deletion flag on this line.
@item @key{DEL}
Move point to previous line and remove the deletion flag on that line.
@item x
Delete the files that are flagged for deletion.
@end table

@kindex d @r{(Dired)}
@findex dired-flag-file-deletion
  You can flag a file for deletion by moving to the line describing
the file and typing @kbd{d} (@code{dired-flag-file-deletion}).  The
deletion flag is visible as a @samp{D} at the beginning of the line.
This command moves point to the next line, so that repeated @kbd{d}
commands flag successive files.  A numeric argument serves as a repeat
count.

@kindex u @r{(Dired deletion)}
@kindex DEL @r{(Dired)}
  The reason for flagging files for deletion, rather than deleting
files immediately, is to reduce the danger of deleting a file
accidentally.  Until you direct Dired to delete the flagged files, you
can remove deletion flags using the commands @kbd{u} and @key{DEL}.
@kbd{u} (@code{dired-unmark}) works just like @kbd{d}, but removes
flags rather than making flags.  @key{DEL}
(@code{dired-unmark-backward}) moves upward, removing flags; it is
like @kbd{u} with argument @minus{}1.

@kindex x @r{(Dired)}
@findex dired-do-flagged-delete
  To delete the flagged files, type @kbd{x}
(@code{dired-do-flagged-delete}).  This command first displays a list
of all the file names flagged for deletion, and requests confirmation
with @kbd{yes}.  If you confirm, Dired deletes the flagged files, then
deletes their lines from the text of the Dired buffer.  The Dired
buffer, with somewhat fewer lines, remains selected.

  If you answer @kbd{no} or quit with @kbd{C-g} when asked to confirm, you
return immediately to Dired, with the deletion flags still present in
the buffer, and no files actually deleted.

@cindex recursive deletion
@vindex dired-recursive-deletes
  You can delete empty directories just like other files, but normally
Dired cannot delete directories that are nonempty.  If the variable
@code{dired-recursive-deletes} is non-@code{nil}, then Dired can
delete nonempty directories including all their contents.  That can
be somewhat risky.

@vindex delete-by-moving-to-trash
  On some systems, there is a facility called the ``Trash'' or
``Recycle Bin'', but Emacs does @emph{not} use it by default.  Thus,
when you delete a file in Dired, it is gone forever.  However, you can
tell Emacs to use the Trash for file deletion, by changing the
variable @code{delete-by-moving-to-trash} to @code{t}.  @xref{Misc
File Ops}, for more information about the Trash.

@node Flagging Many Files
@section Flagging Many Files at Once
@cindex flagging many files for deletion (in Dired)

  The @kbd{#}, @kbd{~}, @kbd{.}, @kbd{% &}, and @kbd{% d} commands
flag many files for deletion, based on their file names:

@table @kbd
@item #
Flag all auto-save files (files whose names start and end with @samp{#})
for deletion (@pxref{Auto Save}).

@item ~
Flag all backup files (files whose names end with @samp{~}) for deletion
(@pxref{Backup}).

@item .@: @r{(Period)}
Flag excess numeric backup files for deletion.  The oldest and newest
few backup files of any one file are exempt; the middle ones are
flagged.

@item % &
Flag for deletion all files with certain kinds of names which suggest
you could easily create those files again.

@item % d @var{regexp} @key{RET}
Flag for deletion all files whose names match the regular expression
@var{regexp}.
@end table

@kindex # @r{(Dired)}
@findex dired-flag-auto-save-files
@cindex deleting auto-save files
  @kbd{#} (@code{dired-flag-auto-save-files}) flags all files whose
names look like auto-save files---that is, files whose names begin and
end with @samp{#}.  @xref{Auto Save}.

@kindex ~ @r{(Dired)}
@findex dired-flag-backup-files
  @kbd{~} (@code{dired-flag-backup-files}) flags all files whose names
say they are backup files---that is, files whose names end in
@samp{~}.  @xref{Backup}.

@kindex . @r{(Dired)}
@vindex dired-kept-versions
@findex dired-clean-directory
  @kbd{.} (period, @code{dired-clean-directory}) flags just some of
the backup files for deletion: all but the oldest few and newest few
backups of any one file.  Normally, the number of newest versions kept
for each file is given by the variable @code{dired-kept-versions}
(@strong{not} @code{kept-new-versions}; that applies only when
saving).  The number of oldest versions to keep is given by the
variable @code{kept-old-versions}.

  Period with a positive numeric argument, as in @kbd{C-u 3 .},
specifies the number of newest versions to keep, overriding
@code{dired-kept-versions}.  A negative numeric argument overrides
@code{kept-old-versions}, using minus the value of the argument to
specify the number of oldest versions of each file to keep.

@kindex % & @r{(Dired)}
@findex dired-flag-garbage-files
@vindex dired-garbage-files-regexp
@cindex deleting some backup files
  @kbd{% &} (@code{dired-flag-garbage-files}) flags files whose names
match the regular expression specified by the variable
@code{dired-garbage-files-regexp}.  By default, this matches certain
files produced by @TeX{}, @samp{.bak} files, and the @samp{.orig} and
@samp{.rej} files produced by @code{patch}.

@findex dired-flag-files-regexp
@kindex % d @r{(Dired)}
  @kbd{% d} flags all files whose names match a specified regular
expression (@code{dired-flag-files-regexp}).  Only the non-directory
part of the file name is used in matching.  You can use @samp{^} and
@samp{$} to anchor matches.  You can exclude certain subdirectories
from marking by hiding them while you use @kbd{% d}.  @xref{Hiding
Subdirectories}.

@node Dired Visiting
@section Visiting Files in Dired

  There are several Dired commands for visiting or examining the files
listed in the Dired buffer.  All of them apply to the current line's
file; if that file is really a directory, these commands invoke Dired on
that subdirectory (making a separate Dired buffer).

@table @kbd
@item f
@kindex f @r{(Dired)}
@findex dired-find-file
Visit the file described on the current line, like typing @kbd{C-x C-f}
and supplying that file name (@code{dired-find-file}).  @xref{Visiting}.

@item @key{RET}
@itemx e
@kindex RET @r{(Dired)}
@kindex e @r{(Dired)}
Equivalent to @kbd{f}.

@ignore  @c This command seems too risky to document at all.
@item a
@kindex a @r{(Dired)}
@findex dired-find-alternate-file
Like @kbd{f}, but replaces the contents of the Dired buffer with
that of an alternate file or directory (@code{dired-find-alternate-file}).
@end ignore

@item o
@kindex o @r{(Dired)}
@findex dired-find-file-other-window
Like @kbd{f}, but uses another window to display the file's buffer
(@code{dired-find-file-other-window}).  The Dired buffer remains visible
in the first window.  This is like using @kbd{C-x 4 C-f} to visit the
file.  @xref{Windows}.

@item C-o
@kindex C-o @r{(Dired)}
@findex dired-display-file
Visit the file described on the current line, and display the buffer in
another window, but do not select that window (@code{dired-display-file}).

@item Mouse-1
@itemx Mouse-2
@findex dired-mouse-find-file-other-window
Visit the file named by the line you click on
(@code{dired-mouse-find-file-other-window}).  This uses another window
to display the file, like the @kbd{o} command.

@item v
@kindex v @r{(Dired)}
@findex dired-view-file
View the file described on the current line, using @kbd{M-x view-file}
(@code{dired-view-file}).  Viewing a file with @code{view-file} is
like visiting it, but is slanted toward moving around in the file
conveniently and does not allow changing the file.  @xref{Misc File
Ops, View File, Miscellaneous File Operations}.

@item ^
@kindex ^ @r{(Dired)}
@findex dired-up-directory
Visit the parent directory of the current directory
(@code{dired-up-directory}).  This is equivalent to moving to the line
for @file{..} and typing @kbd{f} there.
@end table

@node Marks vs Flags
@section Dired Marks vs. Flags

@cindex marking many files (in Dired)
  Instead of flagging a file with @samp{D}, you can @dfn{mark} the
file with some other character (usually @samp{*}).  Most Dired
commands to operate on files use the files marked with @samp{*}.  The
only command that operates on flagged files is @kbd{x}, which deletes
them.

  Here are some commands for marking with @samp{*}, for unmarking, and
for operating on marks.  (@xref{Dired Deletion}, for commands to flag
and unflag files.)

@table @kbd
@item m
@itemx * m
@kindex m @r{(Dired)}
@kindex * m @r{(Dired)}
@findex dired-mark
Mark the current file with @samp{*} (@code{dired-mark}).  With a numeric
argument @var{n}, mark the next @var{n} files starting with the current
file.  (If @var{n} is negative, mark the previous @minus{}@var{n}
files.)

@item * *
@kindex * * @r{(Dired)}
@findex dired-mark-executables
@cindex marking executable files (in Dired)
Mark all executable files with @samp{*}
(@code{dired-mark-executables}).  With a numeric argument, unmark all
those files.

@item * @@
@kindex * @@ @r{(Dired)}
@findex dired-mark-symlinks
@cindex marking symbolic links (in Dired)
Mark all symbolic links with @samp{*} (@code{dired-mark-symlinks}).
With a numeric argument, unmark all those files.

@item * /
@kindex * / @r{(Dired)}
@findex dired-mark-directories
@cindex marking subdirectories (in Dired)
Mark with @samp{*} all files which are directories, except for
@file{.} and @file{..} (@code{dired-mark-directories}).  With a numeric
argument, unmark all those files.

@item * s
@kindex * s @r{(Dired)}
@findex dired-mark-subdir-files
Mark all the files in the current subdirectory, aside from @file{.}
and @file{..} (@code{dired-mark-subdir-files}).

@item u
@itemx * u
@kindex u @r{(Dired)}
@kindex * u @r{(Dired)}
@findex dired-unmark
Remove any mark on this line (@code{dired-unmark}).

@item @key{DEL}
@itemx * @key{DEL}
@kindex * DEL @r{(Dired)}
@findex dired-unmark-backward
@cindex unmarking files (in Dired)
Move point to previous line and remove any mark on that line
(@code{dired-unmark-backward}).

@item * !
@itemx U
@kindex * ! @r{(Dired)}
@kindex U @r{(Dired)}
@findex dired-unmark-all-marks
Remove all marks from all the files in this Dired buffer
(@code{dired-unmark-all-marks}).

@item * ? @var{markchar}
@itemx M-@key{DEL}
@kindex * ? @r{(Dired)}
@kindex M-DEL @r{(Dired)}
@findex dired-unmark-all-files
Remove all marks that use the character @var{markchar}
(@code{dired-unmark-all-files}).  The argument is a single
character---do not use @key{RET} to terminate it.  See the description
of the @kbd{* c} command below, which lets you replace one mark
character with another.

With a numeric argument, this command queries about each marked file,
asking whether to remove its mark.  You can answer @kbd{y} meaning yes,
@kbd{n} meaning no, or @kbd{!} to remove the marks from the remaining
files without asking about them.

@item * C-n
@itemx M-@}
@findex dired-next-marked-file
@kindex * C-n @r{(Dired)}
@kindex M-@} @r{(Dired)}
Move down to the next marked file (@code{dired-next-marked-file})
A file is ``marked'' if it has any kind of mark.

@item * C-p
@itemx M-@{
@findex dired-prev-marked-file
@kindex * C-p @r{(Dired)}
@kindex M-@{ @r{(Dired)}
Move up to the previous marked file (@code{dired-prev-marked-file})

@item t
@itemx * t
@kindex t @r{(Dired)}
@kindex * t @r{(Dired)}
@findex dired-toggle-marks
@cindex toggling marks (in Dired)
Toggle all marks (@code{dired-toggle-marks}): files marked with @samp{*}
become unmarked, and unmarked files are marked with @samp{*}.  Files
marked in any other way are not affected.

@item * c @var{old-markchar} @var{new-markchar}
@kindex * c @r{(Dired)}
@findex dired-change-marks
Replace all marks that use the character @var{old-markchar} with marks
that use the character @var{new-markchar} (@code{dired-change-marks}).
This command is the primary way to create or use marks other than
@samp{*} or @samp{D}.  The arguments are single characters---do not use
@key{RET} to terminate them.

You can use almost any character as a mark character by means of this
command, to distinguish various classes of files.  If @var{old-markchar}
is a space (@samp{ }), then the command operates on all unmarked files;
if @var{new-markchar} is a space, then the command unmarks the files it
acts on.

To illustrate the power of this command, here is how to put @samp{D}
flags on all the files that have no marks, while unflagging all those
that already have @samp{D} flags:

@example
* c D t  * c SPC D  * c t SPC
@end example

This assumes that no files were already marked with @samp{t}.

@item % m @var{regexp} @key{RET}
@itemx * % @var{regexp} @key{RET}
@findex dired-mark-files-regexp
@kindex % m @r{(Dired)}
@kindex * % @r{(Dired)}
Mark (with @samp{*}) all files whose names match the regular expression
@var{regexp} (@code{dired-mark-files-regexp}).  This command is like
@kbd{% d}, except that it marks files with @samp{*} instead of flagging
with @samp{D}.

Only the non-directory part of the file name is used in matching.  Use
@samp{^} and @samp{$} to anchor matches.  You can exclude
subdirectories by temporarily hiding them (@pxref{Hiding
Subdirectories}).

@item % g @var{regexp} @key{RET}
@findex dired-mark-files-containing-regexp
@kindex % g @r{(Dired)}
@cindex finding files containing regexp matches (in Dired)
Mark (with @samp{*}) all files whose @emph{contents} contain a match for
the regular expression @var{regexp}
(@code{dired-mark-files-containing-regexp}).  This command is like
@kbd{% m}, except that it searches the file contents instead of the file
name.

@item C-x u
@itemx C-_
@itemx C-/
@kindex C-_ @r{(Dired)}
@findex dired-undo
Undo changes in the Dired buffer, such as adding or removing
marks (@code{dired-undo}).  @emph{This command does not revert the
actual file operations, nor recover lost files!}  It just undoes
changes in the buffer itself.

In some cases, using this after commands that operate on files can
cause trouble.  For example, after renaming one or more files,
@code{dired-undo} restores the original names in the Dired buffer,
which gets the Dired buffer out of sync with the actual contents of
the directory.
@end table

@node Operating on Files
@section Operating on Files
@cindex operating on files in Dired

  This section describes the basic Dired commands to operate on one file
or several files.  All of these commands are capital letters; all of
them use the minibuffer, either to read an argument or to ask for
confirmation, before they act.  All of them let you specify the
files to manipulate in these ways:

@itemize @bullet
@item
If you give the command a numeric prefix argument @var{n}, it operates
on the next @var{n} files, starting with the current file.  (If @var{n}
is negative, the command operates on the @minus{}@var{n} files preceding
the current line.)

@item
Otherwise, if some files are marked with @samp{*}, the command operates
on all those files.

@item
Otherwise, the command operates on the current file only.
@end itemize

@noindent
Certain other Dired commands, such as @kbd{!} and the @samp{%}
commands, use the same conventions to decide which files to work on.

@vindex dired-dwim-target
@cindex two directories (in Dired)
  Commands which ask for a destination directory, such as those which
copy and rename files or create links for them, try to guess the default
target directory for the operation.  Normally, they suggest the Dired
buffer's default directory, but if the variable @code{dired-dwim-target}
is non-@code{nil}, and if there is another Dired buffer displayed in the
next window, that other buffer's directory is suggested instead.

  Here are the file-manipulating Dired commands that operate on files.

@table @kbd
@findex dired-do-copy
@kindex C @r{(Dired)}
@cindex copying files (in Dired)
@item C @var{new} @key{RET}
Copy the specified files (@code{dired-do-copy}).  The argument @var{new}
is the directory to copy into, or (if copying a single file) the new
name.  This is like the shell command @code{cp}.

@vindex dired-copy-preserve-time
If @code{dired-copy-preserve-time} is non-@code{nil}, then copying
with this command preserves the modification time of the old file in
the copy, like @samp{cp -p}.

@vindex dired-recursive-copies
@cindex recursive copying
The variable @code{dired-recursive-copies} controls whether to copy
directories recursively (like @samp{cp -r}).  The default is
@code{nil}, which means that directories cannot be copied.

@item D
@findex dired-do-delete
@kindex D @r{(Dired)}
Delete the specified files (@code{dired-do-delete}).  This is like the
shell command @code{rm}.

Like the other commands in this section, this command operates on the
@emph{marked} files, or the next @var{n} files.  By contrast, @kbd{x}
(@code{dired-do-flagged-delete}) deletes all @dfn{flagged} files.

@findex dired-do-rename
@kindex R @r{(Dired)}
@cindex renaming files (in Dired)
@cindex moving files (in Dired)
@item R @var{new} @key{RET}
Rename the specified files (@code{dired-do-rename}).  If you rename a
single file, the argument @var{new} is the new name of the file.  If
you rename several files, the argument @var{new} is the directory into
which to move the files (this is like the shell command @code{mv}).

Dired automatically changes the visited file name of buffers associated
with renamed files so that they refer to the new names.

@findex dired-do-hardlink
@kindex H @r{(Dired)}
@cindex hard links (in Dired)
@item H @var{new} @key{RET}
Make hard links to the specified files (@code{dired-do-hardlink}).
This is like the shell command @code{ln}.  The argument @var{new} is
the directory to make the links in, or (if making just one link) the
name to give the link.

@findex dired-do-symlink
@kindex S @r{(Dired)}
@cindex symbolic links (creation in Dired)
@item S @var{new} @key{RET}
Make symbolic links to the specified files (@code{dired-do-symlink}).
This is like @samp{ln -s}.  The argument @var{new} is the directory to
make the links in, or (if making just one link) the name to give the
link.

@findex dired-do-chmod
@kindex M @r{(Dired)}
@cindex changing file permissions (in Dired)
@item M @var{modespec} @key{RET}
Change the mode (also called ``permission bits'') of the specified files
(@code{dired-do-chmod}).  This uses the @code{chmod} program, so
@var{modespec} can be any argument that @code{chmod} can handle.

@findex dired-do-chgrp
@kindex G @r{(Dired)}
@cindex changing file group (in Dired)
@item G @var{newgroup} @key{RET}
Change the group of the specified files to @var{newgroup}
(@code{dired-do-chgrp}).

@findex dired-do-chown
@kindex O @r{(Dired)}
@cindex changing file owner (in Dired)
@item O @var{newowner} @key{RET}
Change the owner of the specified files to @var{newowner}
(@code{dired-do-chown}).  (On most systems, only the superuser can do
this.)

@vindex dired-chown-program
The variable @code{dired-chown-program} specifies the name of the
program to use to do the work (different systems put @code{chown} in
different places).

@findex dired-do-touch
@kindex T @r{(Dired)}
@cindex changing file time (in Dired)
@item T @var{timestamp} @key{RET}
Touch the specified files (@code{dired-do-touch}).  This means
updating their modification times to the present time.  This is like
the shell command @code{touch}.

@findex dired-do-print
@kindex P @r{(Dired)}
@cindex printing files (in Dired)
@item P @var{command} @key{RET}
Print the specified files (@code{dired-do-print}).  You must specify the
command to print them with, but the minibuffer starts out with a
suitable guess made using the variables @code{lpr-command} and
@code{lpr-switches} (the same variables that @code{lpr-buffer} uses;
@pxref{Printing}).

@findex dired-do-compress
@kindex Z @r{(Dired)}
@cindex compressing files (in Dired)
@item Z
Compress the specified files (@code{dired-do-compress}).  If the file
appears to be a compressed file already, uncompress it instead.

@findex dired-do-load
@kindex L @r{(Dired)}
@cindex loading several files (in Dired)
@item L
Load the specified Emacs Lisp files (@code{dired-do-load}).
@xref{Lisp Libraries}.

@findex dired-do-byte-compile
@kindex B @r{(Dired)}
@cindex byte-compiling several files (in Dired)
@item B
Byte compile the specified Emacs Lisp files
(@code{dired-do-byte-compile}).  @xref{Byte Compilation,, Byte
Compilation, elisp, The Emacs Lisp Reference Manual}.

@kindex A @r{(Dired)}
@findex dired-do-search
@cindex search multiple files (in Dired)
@item A @var{regexp} @key{RET}
Search all the specified files for the regular expression @var{regexp}
(@code{dired-do-search}).

This command is a variant of @code{tags-search}.  The search stops at
the first match it finds; use @kbd{M-,} to resume the search and find
the next match.  @xref{Tags Search}.

@kindex Q @r{(Dired)}
@findex dired-do-query-replace-regexp
@cindex search and replace in multiple files (in Dired)
@item Q @var{regexp} @key{RET} @var{to} @key{RET}
Perform @code{query-replace-regexp} on each of the specified files,
replacing matches for @var{regexp} with the string
@var{to} (@code{dired-do-query-replace-regexp}).

This command is a variant of @code{tags-query-replace}.  If you exit the
query replace loop, you can use @kbd{M-,} to resume the scan and replace
more matches.  @xref{Tags Search}.
@end table

@node Shell Commands in Dired
@section Shell Commands in Dired
@cindex shell commands, Dired

@findex dired-do-shell-command
@kindex ! @r{(Dired)}
@kindex X @r{(Dired)}
The Dired command @kbd{!} (@code{dired-do-shell-command}) reads a
shell command string in the minibuffer and runs that shell command on
one or more files.  The files that the shell command operates on are
determined in the usual way for Dired commands (@pxref{Operating on
Files}).  The command @kbd{X} is a synonym for @kbd{!}.

  The command @kbd{&} (@code{dired-do-async-shell-command}) does the
same, except that it runs the shell command asynchronously.  You can
also do this with @kbd{!}, by appending a @samp{&} character to the
end of the shell command.

  For both @kbd{!} and @kbd{&}, the working directory for the shell
command is the top-level directory of the Dired buffer.

  If you tell @kbd{!} or @kbd{&} to operate on more than one file, the
shell command string determines how those files are passed to the
shell command:

@itemize @bullet
@item
If you use @samp{*} surrounded by whitespace in the command string,
then the command runs just once, with the list of file names
substituted for the @samp{*}.  The order of file names is the order of
appearance in the Dired buffer.

Thus, @kbd{! tar cf foo.tar * @key{RET}} runs @code{tar} on the entire
list of file names, putting them into one tar file @file{foo.tar}.

If you want to use @samp{*} as a shell wildcard with whitespace around
it, write @samp{*""}.  In the shell, this is equivalent to @samp{*};
but since the @samp{*} is not surrounded by whitespace, Dired does not
treat it specially.

@item
Otherwise, if the command string contains @samp{?} surrounded by
whitespace, Emacs runs the shell command once @emph{for each file},
substituting the current file name for @samp{?} each time.  You can
use @samp{?} more than once in the command; the same file name
replaces each occurrence.

@item
If the command string contains neither @samp{*} nor @samp{?}, Emacs
runs the shell command once for each file, adding the file name is
added at the end.  For example, @kbd{! uudecode @key{RET}} runs
@code{uudecode} on each file.
@end itemize

  To iterate over the file names in a more complicated fashion, use an
explicit shell loop.  For example, here is how to uuencode each file,
making the output file name by appending @samp{.uu} to the input file
name:

@example
for file in * ; do uuencode "$file" "$file" >"$file".uu; done
@end example

  The @kbd{!} and @kbd{&} commands do not attempt to update the Dired
buffer to show new or modified files, because they don't know what
files will be changed.  Use the @kbd{g} command to update the Dired
buffer (@pxref{Dired Updating}).

  @xref{Single Shell}, for information about running shell commands
outside Dired.

@node Transforming File Names
@section Transforming File Names in Dired

  This section describes Dired commands which alter file names in a
systematic way.  Each command operates on some or all of the marked
files, using a new name made by transforming the existing name.

  Like the basic Dired file-manipulation commands (@pxref{Operating on
Files}), the commands described here operate either on the next
@var{n} files, or on all files marked with @samp{*}, or on the current
file.  (To mark files, use the commands described in @ref{Marks vs
Flags}.)

  All of the commands described in this section work
@emph{interactively}: they ask you to confirm the operation for each
candidate file.  Thus, you can select more files than you actually
need to operate on (e.g., with a regexp that matches many files), and
then filter the selected names by typing @kbd{y} or @kbd{n} when the
command prompts for confirmation.

@table @kbd
@findex dired-upcase
@kindex % u @r{(Dired)}
@cindex upcase file names
@item % u
Rename each of the selected files to an upper-case name
(@code{dired-upcase}).  If the old file names are @file{Foo}
and @file{bar}, the new names are @file{FOO} and @file{BAR}.

@item % l
@findex dired-downcase
@kindex % l @r{(Dired)}
@cindex downcase file names
Rename each of the selected files to a lower-case name
(@code{dired-downcase}).  If the old file names are @file{Foo} and
@file{bar}, the new names are @file{foo} and @file{bar}.

@item % R @var{from} @key{RET} @var{to} @key{RET}
@kindex % R @r{(Dired)}
@findex dired-do-rename-regexp
@itemx % C @var{from} @key{RET} @var{to} @key{RET}
@kindex % C @r{(Dired)}
@findex dired-do-copy-regexp
@itemx % H @var{from} @key{RET} @var{to} @key{RET}
@kindex % H @r{(Dired)}
@findex dired-do-hardlink-regexp
@itemx % S @var{from} @key{RET} @var{to} @key{RET}
@kindex % S @r{(Dired)}
@findex dired-do-symlink-regexp
These four commands rename, copy, make hard links and make soft links,
in each case computing the new name by regular-expression substitution
from the name of the old file.
@end table

  The four regular-expression substitution commands effectively
perform a search-and-replace on the selected file names.  They read
two arguments: a regular expression @var{from}, and a substitution
pattern @var{to}; they match each ``old'' file name against
@var{from}, and then replace the matching part with @var{to}.  You can
use @samp{\&} and @samp{\@var{digit}} in @var{to} to refer to all or
part of what the pattern matched in the old file name, as in
@code{replace-regexp} (@pxref{Regexp Replace}).  If the regular
expression matches more than once in a file name, only the first match
is replaced.

  For example, @kbd{% R ^.*$ @key{RET} x-\& @key{RET}} renames each
selected file by prepending @samp{x-} to its name.  The inverse of this,
removing @samp{x-} from the front of each file name, is also possible:
one method is @kbd{% R ^x-\(.*\)$ @key{RET} \1 @key{RET}}; another is
@kbd{% R ^x- @key{RET} @key{RET}}.  (Use @samp{^} and @samp{$} to anchor
matches that should span the whole file name.)

  Normally, the replacement process does not consider the files'
directory names; it operates on the file name within the directory.  If
you specify a numeric argument of zero, then replacement affects the
entire absolute file name including directory name.  (A non-zero
argument specifies the number of files to operate on.)

  You may want to select the set of files to operate on using the same
regexp @var{from} that you will use to operate on them.  To do this,
mark those files with @kbd{% m @var{from} @key{RET}}, then use the
same regular expression in the command to operate on the files.  To
make this more convenient, the @kbd{%} commands to operate on files
use the last regular expression specified in any @kbd{%} command as a
default.

@node Comparison in Dired
@section File Comparison with Dired
@cindex file comparison (in Dired)
@cindex compare files (in Dired)

  Here are two Dired commands that compare specified files using
@code{diff}.  They show the output in a buffer using Diff mode
(@pxref{Comparing Files}).

@table @kbd
@item =
@findex dired-diff
@kindex = @r{(Dired)}
Compare the current file (the file at point) with another file (the
file at the mark) using the @code{diff} program (@code{dired-diff}).
The file at the mark is the first argument of @code{diff}, and the
file at point is the second argument.  This refers to the ordinary
Emacs mark, not Dired marks; use @kbd{C-@key{SPC}}
(@code{set-mark-command}) to set the mark at the first file's line
(@pxref{Setting Mark}).

@findex dired-backup-diff
@kindex M-= @r{(Dired)}
@item M-=
Compare the current file with its latest backup file
(@code{dired-backup-diff}).  If the current file is itself a backup,
compare it with the file it is a backup of; this way, you can compare
a file with any one of its backups.

The backup file is the first file given to @code{diff}.
@end table

@node Subdirectories in Dired
@section Subdirectories in Dired
@cindex subdirectories in Dired
@cindex expanding subdirectories in Dired

  A Dired buffer displays just one directory in the normal case;
but you can optionally include its subdirectories as well.

  The simplest way to include multiple directories in one Dired buffer is
to specify the options @samp{-lR} for running @code{ls}.  (If you give a
numeric argument when you run Dired, then you can specify these options
in the minibuffer.)  That produces a recursive directory listing showing
all subdirectories at all levels.

  More often, you will want to show only specific subdirectories.  You
can do this with the @kbd{i} command:

@table @kbd
@findex dired-maybe-insert-subdir
@kindex i @r{(Dired)}
@item i
@cindex inserted subdirectory (Dired)
@cindex in-situ subdirectory (Dired)
Insert the contents of a subdirectory later in the buffer.
@end table

Use the @kbd{i} (@code{dired-maybe-insert-subdir}) command on a line
that describes a file which is a directory.  It inserts the contents of
that directory into the same Dired buffer, and moves there.  Inserted
subdirectory contents follow the top-level directory of the Dired
buffer, just as they do in @samp{ls -lR} output.

If the subdirectory's contents are already present in the buffer, the
@kbd{i} command just moves to it.

In either case, @kbd{i} sets the Emacs mark before moving, so @kbd{C-u
C-@key{SPC}} takes you back to the old position in the buffer (the line
describing that subdirectory).  You can also use @samp{^} to return
to the parent directory in the same Dired buffer.

Use the @kbd{l} command (@code{dired-do-redisplay}) to update the
subdirectory's contents.  Use @kbd{C-u k} on the subdirectory header
line to delete the subdirectory (@pxref{Dired Updating}).  You can also
hide and show inserted subdirectories (@pxref{Hiding Subdirectories}).

@ifnottex
@include dired-xtra.texi
@end ifnottex

@node Subdirectory Motion
@section Moving Over Subdirectories

  When a Dired buffer lists subdirectories, you can use the page motion
commands @kbd{C-x [} and @kbd{C-x ]} to move by entire directories
(@pxref{Pages}).

@cindex header line (Dired)
@cindex directory header lines
  The following commands move across, up and down in the tree of
directories within one Dired buffer.  They move to @dfn{directory header
lines}, which are the lines that give a directory's name, at the
beginning of the directory's contents.

@table @kbd
@findex dired-next-subdir
@kindex C-M-n @r{(Dired)}
@item C-M-n
Go to next subdirectory header line, regardless of level
(@code{dired-next-subdir}).

@findex dired-prev-subdir
@kindex C-M-p @r{(Dired)}
@item C-M-p
Go to previous subdirectory header line, regardless of level
(@code{dired-prev-subdir}).

@findex dired-tree-up
@kindex C-M-u @r{(Dired)}
@item C-M-u
Go up to the parent directory's header line (@code{dired-tree-up}).

@findex dired-tree-down
@kindex C-M-d @r{(Dired)}
@item C-M-d
Go down in the directory tree, to the first subdirectory's header line
(@code{dired-tree-down}).

@findex dired-prev-dirline
@kindex < @r{(Dired)}
@item <
Move up to the previous directory-file line (@code{dired-prev-dirline}).
These lines are the ones that describe a directory as a file in its
parent directory.

@findex dired-next-dirline
@kindex > @r{(Dired)}
@item >
Move down to the next directory-file line (@code{dired-prev-dirline}).
@end table

@node Hiding Subdirectories
@section Hiding Subdirectories
@cindex hiding subdirectories (Dired)
@cindex showing hidden subdirectories (Dired)

  @dfn{Hiding} a subdirectory means to make it invisible, except for its
header line.

@table @kbd
@item $
@findex dired-hide-subdir
@kindex $ @r{(Dired)}
Hide or show the subdirectory that point is in, and move point to the
next subdirectory (@code{dired-hide-subdir}).  This is a toggle.  A
numeric argument serves as a repeat count.

@item M-$
@findex dired-hide-all
@kindex M-$ @r{(Dired)}
Hide all subdirectories in this Dired buffer, leaving only their header
lines (@code{dired-hide-all}).  Or, if any subdirectory is currently
hidden, make all subdirectories visible again.  You can use this command
to get an overview in very deep directory trees or to move quickly to
subdirectories far away.
@end table

  Ordinary Dired commands never consider files inside a hidden
subdirectory.  For example, the commands to operate on marked files
ignore files in hidden directories even if they are marked.  Thus you
can use hiding to temporarily exclude subdirectories from operations
without having to remove the Dired marks on files in those
subdirectories.

@xref{Dired Updating}, for how to insert or delete a subdirectory listing.

@node Dired Updating
@section Updating the Dired Buffer
@cindex updating Dired buffer
@cindex refreshing displayed files

  This section describes commands to update the Dired buffer to reflect
outside (non-Dired) changes in the directories and files, and to delete
part of the Dired buffer.

@table @kbd
@item g
Update the entire contents of the Dired buffer (@code{revert-buffer}).

@item l
Update the specified files (@code{dired-do-redisplay}).  You specify the
files for @kbd{l} in the same way as for file operations.

@item k
Delete the specified @emph{file lines}---not the files, just the lines
(@code{dired-do-kill-lines}).

@item s
Toggle between alphabetical order and date/time order
(@code{dired-sort-toggle-or-edit}).

@item C-u s @var{switches} @key{RET}
Refresh the Dired buffer using @var{switches} as
@code{dired-listing-switches}.
@end table

@kindex g @r{(Dired)}
@findex revert-buffer @r{(Dired)}
  Type @kbd{g} (@code{revert-buffer}) to update the contents of the
Dired buffer, based on changes in the files and directories listed.
This preserves all marks except for those on files that have vanished.
Hidden subdirectories are updated but remain hidden.

@kindex l @r{(Dired)}
@findex dired-do-redisplay
  To update only some of the files, type @kbd{l}
(@code{dired-do-redisplay}).  Like the Dired file-operating commands,
this command operates on the next @var{n} files (or previous
@minus{}@var{n} files), or on the marked files if any, or on the
current file.  Updating the files means reading their current status,
then updating their lines in the buffer to indicate that status.

  If you use @kbd{l} on a subdirectory header line, it updates the
contents of the corresponding subdirectory.

@vindex dired-auto-revert-buffer
  If you use @kbd{C-x d} or some other Dired command to visit a
directory that is already being shown in a Dired buffer, Dired
switches to that buffer but does not update it.  If the buffer is not
up-to-date, Dired displays a warning telling you to type @key{g} to
update it.  You can also tell Emacs to revert each Dired buffer
automatically when you revisit it, by setting the variable
@code{dired-auto-revert-buffer} to a non-@code{nil} value.

@kindex k @r{(Dired)}
@findex dired-do-kill-lines
  To delete the specified @emph{file lines} from the buffer---not
delete the files---type @kbd{k} (@code{dired-do-kill-lines}).  Like
the file-operating commands, this command operates on the next @var{n}
files, or on the marked files if any; but it does not operate on the
current file as a last resort.

  If you use @kbd{k} with a numeric prefix argument to kill the line
for a file that is a directory, which you have inserted in the Dired
buffer as a subdirectory, it deletes that subdirectory from the buffer
as well.  Typing @kbd{C-u k} on the header line for a subdirectory
also deletes the subdirectory from the Dired buffer.

  The @kbd{g} command brings back any individual lines that you have
killed in this way, but not subdirectories---you must use @kbd{i} to
reinsert a subdirectory.

@cindex Dired sorting
@cindex sorting Dired buffer
@kindex s @r{(Dired)}
@findex dired-sort-toggle-or-edit
  The files in a Dired buffers are normally listed in alphabetical order
by file names.  Alternatively Dired can sort them by date/time.  The
Dired command @kbd{s} (@code{dired-sort-toggle-or-edit}) switches
between these two sorting modes.  The mode line in a Dired buffer
indicates which way it is currently sorted---by name, or by date.

  @kbd{C-u s @var{switches} @key{RET}} lets you specify a new value for
@code{dired-listing-switches}.

@node Dired and Find
@section Dired and @code{find}
@cindex @code{find} and Dired

  You can select a set of files for display in a Dired buffer more
flexibly by using the @command{find} utility to choose the files.

@findex find-name-dired
  To search for files with names matching a wildcard pattern use
@kbd{M-x find-name-dired}.  It reads arguments @var{directory} and
@var{pattern}, and chooses all the files in @var{directory} or its
subdirectories whose individual names match @var{pattern}.

  The files thus chosen are displayed in a Dired buffer, in which the
ordinary Dired commands are available.

@findex find-grep-dired
  If you want to test the contents of files, rather than their names,
use @kbd{M-x find-grep-dired}.  This command reads two minibuffer
arguments, @var{directory} and @var{regexp}; it chooses all the files
in @var{directory} or its subdirectories that contain a match for
@var{regexp}.  It works by running the programs @command{find} and
@command{grep}.  See also @kbd{M-x grep-find}, in @ref{Grep
Searching}.  Remember to write the regular expression for
@command{grep}, not for Emacs.  (An alternative method of showing
files whose contents match a given regexp is the @kbd{% g
@var{regexp}} command, see @ref{Marks vs Flags}.)

@findex find-dired
  The most general command in this series is @kbd{M-x find-dired},
which lets you specify any condition that @command{find} can test.  It
takes two minibuffer arguments, @var{directory} and @var{find-args};
it runs @command{find} in @var{directory}, passing @var{find-args} to
tell @command{find} what condition to test.  To use this command, you
need to know how to use @command{find}.

@vindex find-ls-option
  The format of listing produced by these commands is controlled by the
variable @code{find-ls-option}, whose default value specifies using
options @samp{-ld} for @code{ls}.  If your listings are corrupted, you
may need to change the value of this variable.

@findex locate
@findex locate-with-filter
@cindex file database (locate)
@vindex locate-command
  The command @kbd{M-x locate} provides a similar interface to the
@command{locate} program.  @kbd{M-x locate-with-filter} is similar, but
keeps only files whose names match a given regular expression.

  These buffers don't work entirely like ordinary Dired buffers: file
operations work, but do not always automatically update the buffer.
Reverting the buffer with @kbd{g} deletes all inserted subdirectories,
and erases all flags and marks.

@node Wdired
@section Editing the Dired Buffer

@cindex wdired mode
@findex wdired-change-to-wdired-mode
  Wdired is a special mode that allows you to perform file operations
by editing the Dired buffer directly (the ``W'' in ``Wdired'' stands
for ``writable.'')  To enter Wdired mode, type @kbd{C-x C-q}
(@code{dired-toggle-read-only}) while in a Dired buffer.
Alternatively, use the @samp{Immediate / Edit File Names} menu item.

@findex wdired-finish-edit
  While in Wdired mode, you can rename files by editing the file names
displayed in the Dired buffer.  All the ordinary Emacs editing
commands, including rectangle operations and @code{query-replace}, are
available for this.  Once you are done editing, type @kbd{C-c C-c}
(@code{wdired-finish-edit}).  This applies your changes and switches
back to ordinary Dired mode.

  Apart from simply renaming files, you can move a file to another
directory by typing in the new file name (either absolute or
relative).  To mark a file for deletion, delete the entire file name.
To change the target of a symbolic link, edit the link target name
which appears next to the link name.

  The rest of the text in the buffer, such as the file sizes and
modification dates, is marked read-only, so you can't edit it.
However, if you set @code{wdired-allow-to-change-permissions} to
@code{t}, you can edit the file permissions.  For example, you can
change @samp{-rw-r--r--} to @samp{-rw-rw-rw-} to make a file
world-writable.  These changes also take effect when you type @kbd{C-c
C-c}.

@node Image-Dired
@section Viewing Image Thumbnails in Dired
@cindex image-dired mode
@cindex image-dired

  Image-Dired is a facility for browsing image files.  It provides viewing
the images either as thumbnails or in full size, either inside Emacs
or through an external viewer.

@kindex C-t d @r{(Image-Dired)}
@findex image-dired-display-thumbs
  To enter Image-Dired, mark the image files you want to look at in
the Dired buffer, using @kbd{m} as usual.  Then type @kbd{C-t d}
(@code{image-dired-display-thumbs}).  This creates and switches to a
buffer containing image-dired, corresponding to the marked files.

  You can also enter Image-Dired directly by typing @kbd{M-x
image-dired}.  This prompts for a directory; specify one that has
image files.  This creates thumbnails for all the images in that
directory, and displays them all in the ``thumbnail buffer.''  This
takes a long time if the directory contains many image files, and it
asks for confirmation if the number of image files exceeds
@code{image-dired-show-all-from-dir-max-files}.

  With point in the thumbnail buffer, you can type @kbd{RET}
(@code{image-dired-display-thumbnail-original-image}) to display a
sized version of it in another window.  This sizes the image to fit
the window.  Use the arrow keys to move around in the buffer.  For
easy browsing, use @kbd{SPC}
(@code{image-dired-display-next-thumbnail-original}) to advance and
display the next image.  Typing @kbd{DEL}
(@code{image-dired-display-previous-thumbnail-original}) backs up to
the previous thumbnail and displays that instead.

@vindex image-dired-external-viewer
  To view and the image in its original size, either provide a prefix
argument (@kbd{C-u}) before pressing @kbd{RET}, or type
@kbd{C-@key{RET}} (@code{image-dired-thumbnail-display-external}) to
display the image in an external viewer.  You must first configure
@code{image-dired-external-viewer}.

  You can delete images through Image-Dired also.  Type @kbd{d}
(@code{image-dired-flag-thumb-original-file}) to flag the image file
for deletion in the Dired buffer.  You can also delete the thumbnail
image from the thumbnail buffer with @kbd{C-d}
(@code{image-dired-delete-char}).

  More advanced features include @dfn{image tags}, which are metadata
used to categorize image files.  The tags are stored in a plain text
file configured by @code{image-dired-db-file}.

  To tag image files, mark them in the dired buffer (you can also mark
files in Dired from the thumbnail buffer by typing @kbd{m}) and type
@kbd{C-t t} (@code{image-dired-tag-files}).  This reads the tag name
in the minibuffer.  To mark files having a certain tag, type @kbd{C-t f}
(@code{image-dired-mark-tagged-files}).  After marking image files
with a certain tag, you can use @kbd{C-t d} to view them.

  You can also tag a file directly from the thumbnail buffer by typing
@kbd{t t} and you can remove a tag by typing @kbd{t r}.  There is also
a special ``tag'' called ``comment'' for each file (it is not a tag in
the exact same sense as the other tags, it is handled slightly
different).  That is used to enter a comment or description about the
image.  You comment a file from the thumbnail buffer by typing
@kbd{c}.  You will be prompted for a comment.  Type @kbd{C-t c} to add
a comment from Dired (@code{image-dired-dired-comment-files}).

  Image-Dired also provides simple image manipulation.  In the
thumbnail buffer, type @kbd{L} to rotate the original image 90 degrees
anti clockwise, and @kbd{R} to rotate it 90 degrees clockwise.  This
rotation is lossless, and uses an external utility called JpegTRAN.

@node Misc Dired Features
@section Other Dired Features

@kindex + @r{(Dired)}
@findex dired-create-directory
  The command @kbd{+} (@code{dired-create-directory}) reads a
directory name, and creates the directory if it does not already
exist.

@cindex searching multiple files via Dired
  The command @kbd{M-s a C-s} (@code{dired-do-isearch}) begins a
``multi-file'' incremental search on the marked files.  If a search
fails at the end of a file, typing @kbd{C-s} advances to the next
marked file and repeats the search; at the end of the last marked
file, the search wraps around to the first marked file.  The command
@kbd{M-s a M-C-s} (@code{dired-do-isearch-regexp}) does the same with
a regular expression search.  @xref{Repeat Isearch}, for information
about search repetition.

@cindex Adding to the kill ring in Dired.
@kindex w @r{(Dired)}
@findex dired-copy-filename-as-kill
  The command @kbd{w} (@code{dired-copy-filename-as-kill}) puts the
names of the marked (or next @var{n}) files into the kill ring, as if
you had killed them with @kbd{C-w}.  The names are separated by a
space.

  With a zero prefix argument, this uses the absolute file name of
each marked file.  With just @kbd{C-u} as the prefix argument, it uses
file names relative to the Dired buffer's default directory.  (This
can still contain slashes if in a subdirectory.)  As a special case,
if point is on a directory headerline, @kbd{w} gives you the absolute
name of that directory.  Any prefix argument or marked files are
ignored in this case.

  The main purpose of this command is so that you can yank the file
names into arguments for other Emacs commands.  It also displays what
it added to the kill ring, so you can use it to display the list of
currently marked files in the echo area.

@cindex Dired and version control
  If the directory you are visiting is under version control
(@pxref{Version Control}), then the normal VC diff and log commands
will operate on the selected files.

@findex dired-compare-directories
  The command @kbd{M-x dired-compare-directories} is used to compare
the current Dired buffer with another directory.  It marks all the files
that are ``different'' between the two directories.  It puts these marks
in all Dired buffers where these files are listed, which of course includes
the current buffer.

  The default comparison method (used if you type @key{RET} at the
prompt) is to compare just the file names---each file name that does
not appear in the other directory is ``different.''  You can specify
more stringent comparisons by entering a Lisp expression, which can
refer to the variables @code{size1} and @code{size2}, the respective
file sizes; @code{mtime1} and @code{mtime2}, the last modification
times in seconds, as floating point numbers; and @code{fa1} and
@code{fa2}, the respective file attribute lists (as returned by the
function @code{file-attributes}).  This expression is evaluated for
each pair of like-named files, and if the expression's value is
non-@code{nil}, those files are considered ``different.''

  For instance, the sequence @code{M-x dired-compare-directories
@key{RET} (> mtime1 mtime2) @key{RET}} marks files newer in this
directory than in the other, and marks files older in the other
directory than in this one.  It also marks files with no counterpart,
in both directories, as always.

@cindex drag and drop, Dired
  On the X window system, Emacs supports the ``drag and drop''
protocol.  You can drag a file object from another program, and drop
it onto a Dired buffer; this either moves, copies, or creates a link
to the file in that directory.  Precisely which action is taken is
determined by the originating program.  Dragging files out of a Dired
buffer is currently not supported.

@ignore
   arch-tag: d105f9b9-fc1b-4c5f-a949-9b2cf3ca2fc1
@end ignore