-you had killed them with @kbd{C-w}. With a zero prefix argument
-@var{n}=0, use the absolute file name of each marked file. With just
-@kbd{C-u} as the prefix argument, use the relative file name of each
-marked file. As a special case, if no prefix argument is given and
-point is on a directory headerline, @kbd{w} gives you the name of that
-directory without looking for marked files.
-
-@vindex dired-marked-files
-The main purpose of the @kbd{w} command is so that you can yank the
-file names into arguments for other Emacs commands. It also displays
-what was pushed onto the kill ring, so you can use it to display the
-list of currently marked files in the echo area. It also stores the
-list of names in the variable @code{dired-marked-files}, for use in
-Lisp expressions.
-@end table
+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.
+
+@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.