(shell-command-default-error-buffer): Renamed from

shell-command-on-region-default-error-buffer.
(shell-command-on-region): Mention in echo area when there
is some error output.  Mention success or failure, too.
Accumulate multiple error outputs
going forward, with formfeed in between.  Display the error buffer
when we have put something in it.
(shell-command): Add the ERROR-BUFFER argument feature.

lisp/simple.el

@@ -1077,7 +1077,13 @@ is not *inside* the region START...END."
 (defvar shell-command-switch "-c"
   "Switch used to have the shell execute its command line argument.")
 
-(defun shell-command (command &optional output-buffer)
+(defvar shell-command-default-error-buffer nil
+  "*Buffer name for `shell-command' and `shell-command-on-region' error output.
+This buffer is used when `shell-command' or 'shell-command-on-region'
+is run interactively.  A value of nil means that output to stderr and
+stdout will be intermixed in the output stream.")
+
+(defun shell-command (command &optional output-buffer error-buffer)
   "Execute string COMMAND in inferior shell; display output, if any.
 
 If COMMAND ends in ampersand, execute it asynchronously.
@@ -1104,34 +1110,64 @@ says to put the output in some other buffer.
 If OUTPUT-BUFFER is a buffer or buffer name, put the output there.
 If OUTPUT-BUFFER is not a buffer and not nil,
 insert output in current buffer.  (This cannot be done asynchronously.)
-In either case, the output is inserted after point (leaving mark after it)."
+In either case, the output is inserted after point (leaving mark after it).
+
+If the optional third argument ERROR-BUFFER is non-nil, it is a buffer
+or buffer name to which to direct the command's standard error output.
+If it is nil, error output is mingled with regular output.
+In an interactive call, the variable `shell-command-default-error-buffer'
+specifies the value of ERROR-BUFFER."
+
   (interactive (list (read-from-minibuffer "Shell command: "
 					   nil nil nil 'shell-command-history)
-		     current-prefix-arg))
+		     current-prefix-arg
+		     shell-command-default-error-buffer))
   ;; Look for a handler in case default-directory is a remote file name.
   (let ((handler
 	 (find-file-name-handler (directory-file-name default-directory)
 				 'shell-command)))
     (if handler
-	(funcall handler 'shell-command command output-buffer)
+	(funcall handler 'shell-command command output-buffer error-buffer)
       (if (and output-buffer
 	       (not (or (bufferp output-buffer)  (stringp output-buffer))))
-	  (progn (barf-if-buffer-read-only)
-		 (push-mark)
-		 ;; We do not use -f for csh; we will not support broken use of
-		 ;; .cshrcs.  Even the BSD csh manual says to use
-		 ;; "if ($?prompt) exit" before things which are not useful
-		 ;; non-interactively.  Besides, if someone wants their other
-		 ;; aliases for shell commands then they can still have them.
-		 (call-process shell-file-name nil t nil
-			       shell-command-switch command)
-		 ;; This is like exchange-point-and-mark, but doesn't
-		 ;; activate the mark.  It is cleaner to avoid activation,
-		 ;; even though the command loop would deactivate the mark
-		 ;; because we inserted text.
-		 (goto-char (prog1 (mark t)
-			      (set-marker (mark-marker) (point)
-					  (current-buffer)))))
+	  (let ((error-file
+		 (if error-buffer 
+		     (concat (file-name-directory temp-file-name-pattern)
+			     (make-temp-name "scor"))
+		   nil)))
+	    (barf-if-buffer-read-only)
+	    (push-mark)
+	    ;; We do not use -f for csh; we will not support broken use of
+	    ;; .cshrcs.  Even the BSD csh manual says to use
+	    ;; "if ($?prompt) exit" before things which are not useful
+	    ;; non-interactively.  Besides, if someone wants their other
+	    ;; aliases for shell commands then they can still have them.
+	    (call-process shell-file-name nil 
+			  (if error-file
+			      (list t error-file)
+			    t)
+			  nil shell-command-switch command)
+	    (when (and error-file (file-exists-p error-file))
+	      (if (< 0 (nth 7 (file-attributes error-file)))
+		  (with-current-buffer (get-buffer-create error-buffer)
+		    (let ((pos-from-end (- (point-max) (point))))
+		      (or (bobp)
+			  (insert "\f\n"))
+		      ;; Do no formatting while reading error file,
+		      ;; because that can run a shell command, and we
+		      ;; don't want that to cause an infinite recursion.
+		      (format-insert-file error-file nil)
+		      ;; Put point after the inserted errors.
+		      (goto-char (- (point-max) pos-from-end)))
+		    (display-buffer (current-buffer))))
+	      (delete-file error-file))
+	    ;; This is like exchange-point-and-mark, but doesn't
+	    ;; activate the mark.  It is cleaner to avoid activation,
+	    ;; even though the command loop would deactivate the mark
+	    ;; because we inserted text.
+	    (goto-char (prog1 (mark t)
+			 (set-marker (mark-marker) (point)
+				     (current-buffer)))))
 	;; Preserve the match data in case called from a program.
 	(save-match-data
 	  (if (string-match "[ \t]*&[ \t]*$" command)
@@ -1160,8 +1196,8 @@ In either case, the output is inserted after point (leaving mark after it)."
 		  (require 'shell) (shell-mode)
 		  (set-process-sentinel proc 'shell-command-sentinel)
 		  ))
-	    (shell-command-on-region (point) (point) command output-buffer)
-	    ))))))
+	    (shell-command-on-region (point) (point) command
+				     output-buffer nil error-buffer)))))))
 
 ;; We have a sentinel to prevent insertion of a termination message
 ;; in the buffer itself.
@@ -1171,12 +1207,6 @@ In either case, the output is inserted after point (leaving mark after it)."
 	       (car (cdr (cdr (process-command process))))
 	       (substring signal 0 -1))))
 
-(defvar shell-command-on-region-default-error-buffer nil
-  "*Name of buffer that `shell-command-on-region' uses for stderr.
-This buffer is used when `shell-command-on-region' is run interactively.
-A nil value for this variable means that output to stderr and stdout
-will be intermixed in the output stream.")
-
 (defun shell-command-on-region (start end command
 				      &optional output-buffer replace
 				      error-buffer)
@@ -1217,9 +1247,8 @@ around it.
 If optional sixth argument ERROR-BUFFER is non-nil, it is a buffer
 or buffer name to which to direct the command's standard error output.
 If it is nil, error output is mingled with regular output.
-In an interactive call, the variable
-`shell-command-on-region-default-error-buffer' specifies the value
-of ERROR-BUFFER."
+In an interactive call, the variable `shell-command-default-error-buffer'
+specifies the value of ERROR-BUFFER."
   (interactive (let ((string
 		      ;; Do this before calling region-beginning
 		      ;; and region-end, in case subprocess output
@@ -1233,7 +1262,7 @@ of ERROR-BUFFER."
 		       string
 		       current-prefix-arg
 		       current-prefix-arg
-		       shell-command-on-region-default-error-buffer)))
+		       shell-command-default-error-buffer)))
   (let ((error-file
 	 (if error-buffer 
 	     (concat (file-name-directory temp-file-name-pattern)
@@ -1300,13 +1329,18 @@ of ERROR-BUFFER."
 			     0
 			   (count-lines (point-min) (point-max))))))
 	    (cond ((= lines 0)
-		   (if success
-		       (message "(Shell command %sed with no output)"
+		   (if (and error-file
+			    (< 0 (nth 7 (file-attributes error-file))))
+		       (message "(Shell command %sed with some error output)"
 				(if (equal 0 exit-status)
 				    "succeed"
-				  "fail")))
+				  "fail"))
+		     (message "(Shell command %sed with no output)"
+			      (if (equal 0 exit-status)
+				  "succeed"
+				"fail")))
 		   (kill-buffer buffer))
-		  ((and success (= lines 1))
+		  ((= lines 1)
 		   (message "%s"
 			    (save-excursion
 			      (set-buffer buffer)
@@ -1318,12 +1352,20 @@ of ERROR-BUFFER."
 		     (set-buffer buffer)
 		     (goto-char (point-min)))
 		   (display-buffer buffer)))))))
-    (if (and error-file (file-exists-p error-file))
-	(save-excursion
-	  (set-buffer (get-buffer-create error-buffer))
-	  ;; Do no formatting while reading error file, for fear of looping.
-	  (format-insert-file error-file nil)
-	  (delete-file error-file)))
+    (when (and error-file (file-exists-p error-file))
+      (if (< 0 (nth 7 (file-attributes error-file)))
+	  (with-current-buffer (get-buffer-create error-buffer)
+	    (let ((pos-from-end (- (point-max) (point))))
+	      (or (bobp)
+		  (insert "\f\n"))
+	      ;; Do no formatting while reading error file,
+	      ;; because that can run a shell command, and we
+	      ;; don't want that to cause an infinite recursion.
+	      (format-insert-file error-file nil)
+	      ;; Put point after the inserted errors.
+	      (goto-char (- (point-max) pos-from-end)))
+	    (display-buffer (current-buffer))))
+      (delete-file error-file))
     exit-status))
        
 (defun shell-command-to-string (command)