From: pjb@informatimago.com (Pascal J. Bourguignon)
To: help-gnu-emacs@gnu.org
Subject: Re: system-command-exists-p
Date: Mon, 07 Dec 2009 11:13:10 +0100 [thread overview]
Message-ID: <87bpibf5xl.fsf@galatea.local> (raw)
In-Reply-To: mailman.12411.1260170302.2239.help-gnu-emacs@gnu.org
Andreas Roehler <andreas.roehler@online.de> writes:
> Hi,
>
> needed a check if a command exists on system.
> Employed the following:
>
> (defun system-command-exists-p (command)
> "Return t if COMMAND is available on system. "
> (let* ((cmd (format "type %s" command)))
> (eq 0 (shell-command cmd))))
>
> Any comments/suggestions?
Use %S or (shell-quote-argument command).
type is a built-in command specific to the sh familly of shells.
Perhaps it would be a good idea to explicitely call up sh?
It may be useful to return the path of the command:
(defun system-command-exists-p (command)
"Return t if COMMAND is available on system. "
(let* ((cmd (format "/bin/sh -c 'type %s'"
(shell-quote-argument command))))
(when (eql 0 (shell-command cmd))
(let ((result (shell-command-to-string cmd)))
(if (string-match "^.* is \\(.*\\)\n$"result)
(match-string 1 result)
result)))))
(mapcar (function system-command-exists-p)
'("cat" "type" "foo"))
--> ("/bin/cat" "a shell builtin" nil)
--
__Pascal Bourguignon__
next parent reply other threads:[~2009-12-07 10:13 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <mailman.12411.1260170302.2239.help-gnu-emacs@gnu.org>
2009-12-07 10:13 ` Pascal J. Bourguignon [this message]
2009-12-07 12:02 ` system-command-exists-p Andreas Röhler
[not found] ` <mailman.12419.1260187409.2239.help-gnu-emacs@gnu.org>
2009-12-07 13:44 ` system-command-exists-p Pascal J. Bourguignon
2009-12-07 16:22 ` system-command-exists-p Andreas Politz
2009-12-07 16:00 ` system-command-exists-p Stefan Monnier
2009-12-07 18:57 ` system-command-exists-p Andreas Röhler
2009-12-07 7:17 system-command-exists-p Andreas Roehler
2009-12-07 16:30 ` system-command-exists-p Lennart Borgman
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