Re: & and M-& to run programs asynchronously

[Juri Linkov]

>>>> We could even improve the command `dired-flag-garbage-files' to allow the
>>>> user to modify its default regexp value in the minibuffer after typing `% 
>>>> &'.
>>>
>>>   Maybe just if you prefix it with C-u ?
>>
>> C-u will make it inconsistent with a similar command % m 
>> (`dired-mark-files-regexp')
>> where a prefix argument means to *unmark* files matching a regexp.
>
> So does % g, but % d does not. And I don't see that it should it be a
> problem considering that `dired-flag-garbage-files' does not use the
> prefix argument today. We decide what it should do.

Right, so let's not worry about arguments of `dired-flag-garbage-files' now.

So below is an initial version of a new command `dired-do-async-shell-command'.
Its name is formed by analogy with the buffer name "*Async Shell Command*".
Currently it simply adds & at the end of the asynchronous command.

As for not asking a question "A command is running.  Kill it? "
I think this should be implemented with a new option in simple.el.

Index: lisp/dired.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/dired.el,v
retrieving revision 1.402
diff -c -r1.402 dired.el
*** lisp/dired.el       19 Jul 2008 23:55:41 -0000      1.402
--- lisp/dired.el       22 Jul 2008 22:47:37 -0000
***************
*** 1194,1200 ****
      (define-key map "#" 'dired-flag-auto-save-files)
      (define-key map "." 'dired-clean-directory)
      (define-key map "~" 'dired-flag-backup-files)
-     (define-key map "&" 'dired-flag-garbage-files)
      ;; Upper case keys (except !) for operating on the marked files
      (define-key map "A" 'dired-do-search)
      (define-key map "C" 'dired-do-copy)
--- 1195,1200 ----
***************
*** 1213,1218 ****
--- 1213,1219 ----
      (define-key map "X" 'dired-do-shell-command)
      (define-key map "Z" 'dired-do-compress)
      (define-key map "!" 'dired-do-shell-command)
+     (define-key map "&" 'dired-do-async-shell-command)
      ;; Comparison commands
      (define-key map "=" 'dired-diff)
      (define-key map "\M-=" 'dired-backup-diff)
***************
*** 1240,1245 ****
--- 1241,1247 ----
      (define-key map "%H" 'dired-do-hardlink-regexp)
      (define-key map "%R" 'dired-do-rename-regexp)
      (define-key map "%S" 'dired-do-symlink-regexp)
+     (define-key map "%&" 'dired-flag-garbage-files)
      ;; Commands for marking and unmarking.
      (define-key map "*" nil)
      (define-key map "**" 'dired-mark-executables)

Index: lisp/dired-aux.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/dired-aux.el,v
retrieving revision 1.170
diff -c -r1.170 dired-aux.el
*** lisp/dired-aux.el   6 May 2008 07:57:30 -0000       1.170
--- lisp/dired-aux.el   22 Jul 2008 22:43:45 -0000
***************
*** 490,495 ****
--- 490,515 ----
       (format prompt (dired-mark-prompt arg files))
       nil nil)))
  
+ ;;;###autoload
+ (defun dired-do-async-shell-command (command &optional arg file-list)
+   "Run a shell command COMMAND on the marked files asynchronously.
+ 
+ Like `dired-do-shell-command', but if COMMAND doesn't end in ampersand,
+ adds ampersand and executes the command asynchronously.
+ The output appears in the buffer `*Async Shell Command*'."
+   (interactive
+    (let ((files (dired-get-marked-files t current-prefix-arg)))
+      (list
+       ;; Want to give feedback whether this file or marked files are used:
+       (dired-read-shell-command "& on %s: " current-prefix-arg files)
+       current-prefix-arg
+       files)))
+   (unless (string-match "[*?][ \t]*\\'" command)
+     (setq command (concat command " *")))
+   (unless (string-match "&[ \t]*\\'" command)
+     (setq command (concat command " &")))
+   (dired-do-shell-command command arg file-list))
+ 
  ;; The in-background argument is only needed in Emacs 18 where
  ;; shell-command doesn't understand an appended ampersand `&'.
  ;;;###autoload

-- 
Juri Linkov
http://www.jurta.org/emacs/