* lisp/dired-aux.el (dired-do-chxxx): Use `eq' to detect empty input.

Fixes: debbugs:12399

lisp/ChangeLog

+2012-09-13  Juri Linkov  <juri@jurta.org>
+
+	* dired-aux.el (dired-do-chxxx): Use `eq' to detect empty input.
+	(Bug#12399)
+
 2012-09-13  Glenn Morris  <rgm@gnu.org>
 	* calc/calc.el (math-compose-expr):

lisp/dired-aux.el

@@ -244,7 +244,10 @@ List has a form of (file-name full-file-name (attribute-list))."
 			     (function dired-check-process)
 			     (append
 			      (list operation program)
-			      (unless (string-equal new-attribute "")
+			      (unless (or (string-equal new-attribute "")
+					  ;; Use `eq' instead of `equal'
+					  ;; to detect empty input (bug#12399).
+					  (eq new-attribute default))
 				(if (eq op-symbol 'touch)
 				    (list "-t" new-attribute)
 				  (list new-attribute)))