Some doc for delete-duplicate-lines

* doc/emacs/killing.texi (Deletion): Mention delete-duplicate-lines.

* lisp/sort.el (delete-duplicate-lines): Doc fix.

* etc/NEWS: Related edit.

doc/emacs/ChangeLog

+2014-01-26  Glenn Morris  <rgm@gnu.org>
+
+	* killing.texi (Deletion): Mention delete-duplicate-lines.
+
 2014-01-24  Glenn Morris  <rgm@gnu.org>
 
 	* ack.texi (Acknowledgments): No longer mention obsolete xesam.el,

doc/emacs/killing.texi

@@ -136,6 +136,17 @@ the current line).  On a solitary blank line, it deletes that line.
 previous line, by deleting a newline and all surrounding spaces, usually
 leaving a single space.  @xref{Indentation,M-^}.
 
+@c Not really sure where to put this...
+@findex delete-duplicate-lines
+  The command @code{delete-duplicate-lines} searches the region for
+identical lines, and removes all but one copy of each.  Normally it
+keeps the first instance of each repeated line, but with a @kbd{C-u}
+prefix argument it keeps the last.  With a @kbd{C-u C-u} prefix
+argument, it only searches for adjacent identical lines.  This is a
+more efficient mode of operation, useful when the lines have already
+been sorted.  With a @kbd{C-u C-u C-u} prefix argument, it retains
+repeated blank lines.
+
 @node Killing by Lines
 @subsection Killing by Lines
 

etc/NEWS

@@ -312,12 +312,10 @@ macros in registers.
 *** New command `C-x r f' (`frameset-to-register').
 See Changes in Emacs 24.4, above.
 
++++
 ** New command `delete-duplicate-lines'.
-When its arg ADJACENT is non-nil (when called interactively with C-u
-C-u) it works like the utility `uniq'.  Otherwise by default it
-deletes duplicate lines everywhere in the region without regard to
-adjacency.  When its arg KEEP-BLANKS is non-nil (when called
-interactively with C-u C-u C-u), duplicate blank lines are preserved.
+This searches the region for identical lines, and removes all but one
+copy of each repeated line.  The lines need not be sorted.
 
 
 * Changes in Specialized Modes and Packages in Emacs 24.4

lisp/ChangeLog

+2014-01-26  Glenn Morris  <rgm@gnu.org>
+
+	* sort.el (delete-duplicate-lines): Doc fix.
+
 2014-01-25  Rüdiger Sonderfeld  <ruediger@c-plusplus.de>
 
 	* progmodes/ada-mode.el (ada):

lisp/sort.el

@@ -570,25 +570,23 @@ From a program takes two point or marker arguments, BEG and END."
 ;;;###autoload
 (defun delete-duplicate-lines (beg end &optional reverse adjacent keep-blanks
                                interactive)
-  "Delete duplicate lines in the region between BEG and END.
-
-If REVERSE is nil, search and delete duplicates forward keeping the first
-occurrence of duplicate lines.  If REVERSE is non-nil (when called
-interactively with C-u prefix), search and delete duplicates backward
-keeping the last occurrence of duplicate lines.
-
-If ADJACENT is non-nil (when called interactively with two C-u prefixes),
-delete repeated lines only if they are adjacent.  It works like the utility
-`uniq' and is useful when lines are already sorted in a large file since
-this is more efficient in performance and memory usage than when ADJACENT
-is nil that uses additional memory to remember previous lines.
-
-If KEEP-BLANKS is non-nil (when called interactively with three C-u prefixes),
-duplicate blank lines are preserved.
-
-When called from Lisp and INTERACTIVE is omitted or nil, return the number
-of deleted duplicate lines, do not print it; if INTERACTIVE is t, the
-function behaves in all respects as if it had been called interactively."
+  "Delete all but one copy of any identical lines in the region.
+Non-interactively, arguments BEG and END delimit the region.
+Normally it searches forwards, keeping the first instance of
+each identical line.  If REVERSE is non-nil (interactively, with
+a C-u prefix), it searches backwards and keeps the last instance of
+each repeated line.
+
+Identical lines need not be adjacent, unless the argument
+ADJACENT is non-nil (interactively, with a C-u C-u prefix).
+This is a more efficient mode of operation, and may be useful
+on large regions that have already been sorted.
+
+If the argument KEEP-BLANKS is non-nil (interactively, with a
+C-u C-u C-u prefix), it retains repeated blank lines.
+
+Returns the number of deleted lines.  Interactively, or if INTERACTIVE
+is non-nil, it also prints a message describing the number of deletions."
   (interactive
    (progn
      (barf-if-buffer-read-only)