Merge from emacs--rel--22

[bpt/emacs.git] / lisp / eshell / em-unix.el

diff --git a/lisp/eshell/em-unix.el b/lisp/eshell/em-unix.el
index 850d51d..e970c87 100644 (file)
--- a/lisp/eshell/em-unix.el
+++ b/lisp/eshell/em-unix.el
@@ -22,9 +22,22 @@
 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 ;; Boston, MA 02110-1301, USA.
 
-(provide 'em-unix)
+;;; Commentary:
+
+;; This file contains implementations of several UNIX command in Emacs
+;; Lisp, for several reasons:
+;;
+;;   1) it makes them available on all platforms where the Lisp
+;;      functions used are available
+;;
+;;   2) it makes their functionality accessible and modified by the
+;;      Lisp programmer.
+;;
+;;   3) it allows Eshell to refrain from having to invoke external
+;;      processes for common operations.
+
+;;; Code:
 
-(eval-when-compile (require 'esh-maint))
 (require 'eshell)
 
 (defgroup eshell-unix nil
@@ -40,20 +53,6 @@ by name)."
   :tag "UNIX commands in Lisp"
   :group 'eshell-module)
 
-;;; Commentary:
-
-;; This file contains implementations of several UNIX command in Emacs
-;; Lisp, for several reasons:
-;;
-;;   1) it makes them available on all platforms where the Lisp
-;;      functions used are available
-;;
-;;   2) it makes their functionality accessible and modified by the
-;;      Lisp programmer.
-;;
-;;   3) it allows Eshell to refrain from having to invoke external
-;;      processes for common operations.
-
 (defcustom eshell-unix-load-hook '(eshell-unix-initialize)
   "*A list of functions to run when `eshell-unix' is loaded."
   :type 'hook
@@ -78,7 +77,7 @@ receiving side of a command pipeline."
   :type 'boolean
   :group 'eshell-unix)
 
-(defcustom eshell-plain-locate-behavior (eshell-under-xemacs-p)
+(defcustom eshell-plain-locate-behavior (featurep 'xemacs)
   "*If non-nil, standalone \"locate\" commands will behave normally.
 Standalone in this context means not redirected, and not on the
 receiving side of a command pipeline."
@@ -137,8 +136,6 @@ Otherwise, Emacs will attempt to use rsh to invoke du on the remote machine."
   :type 'boolean
   :group 'eshell-unix)
 
-(require 'esh-opt)
-
 ;;; Functions:
 
 (defun eshell-unix-initialize ()
@@ -169,7 +166,7 @@ Otherwise, Emacs will attempt to use rsh to invoke du on the remote machine."
 (put 'eshell/man 'eshell-no-numeric-conversions t)
 
 (defun eshell/info (&rest args)
-  "Runs the info command in-frame with the same behaviour as command-line `info', ie:
+  "Run the info command in-frame with the same behavior as command-line `info', ie:
   'info'           => goes to top info window
   'info arg1'      => IF arg1 is a file, then visits arg1
   'info arg1'      => OTHERWISE goes to top info window and then menu item arg1
@@ -974,6 +971,12 @@ Show wall-clock time elapsed during execution of COMMAND.")
   (if eshell-diff-window-config
       (set-window-configuration eshell-diff-window-config)))
 
+(defun nil-blank-string (string)
+  "Return STRING, or nil if STRING contains only non-blank characters."
+  (cond
+    ((string-match "[^[:blank:]]" string) string)
+    (nil)))
+
 (defun eshell/diff (&rest args)
   "Alias \"diff\" to call Emacs `diff' function."
   (let ((orig-args (eshell-stringify-list (eshell-flatten-list args))))
@@ -995,7 +998,8 @@ Show wall-clock time elapsed during execution of COMMAND.")
          (setcdr (last args 3) nil))
        (with-current-buffer
            (condition-case err
-               (diff old new (eshell-flatten-and-stringify args))
+               (diff old new
+                     (nil-blank-string (eshell-flatten-and-stringify args)))
              (error
               (throw 'eshell-replace-command
                      (eshell-parse-command "*diff" orig-args))))
@@ -1043,7 +1047,7 @@ Show wall-clock time elapsed during execution of COMMAND.")
 
 (put 'eshell/occur 'eshell-no-numeric-conversions t)
 
-;;; Code:
+(provide 'em-unix)
 
 ;;; arch-tag: 2462edd2-a76a-4cf2-897d-92e9a82ac1c9
 ;;; em-unix.el ends here