From: Vincent Lefevre <vincent@vinc17.net>
To: zsh-workers@zsh.org
Subject: Re: [patch] "which"-builtin writes diagnostics to stdout
Date: Wed, 2 Sep 2015 15:48:25 +0200 [thread overview]
Message-ID: <20150902134825.GA11520@ypig.lip.ens-lyon.fr> (raw)
In-Reply-To: <20150902095317.60d38ff0@pwslap01u.europe.root.pri>
On 2015-09-02 09:53:17 +0100, Peter Stephenson wrote:
> On Tue, 1 Sep 2015 16:16:30 -0700
> Bart Schaefer <schaefer@brasslantern.com> wrote:
> > On Sep 1, 8:12am, Mikael Magnusson wrote:
> > }
> > } I guess the problem here is that in other shells, whence does not
> > } exist, and which prints 'not found' to stderr.
> >
> > As far as I can tell, in other shells "which notacommand" prints NOTHING
> > on stdout or stderr.
The other shells (bash, dash, ksh93, mksh, posh) do not have a "which"
builtin:
which -foo
gives the following error under GNU/Linux (Debian):
Illegal option -f
Usage: /usr/bin/which [-a] args
and I confirm that "which notacommand" prints nothing. The "which"
builtin from BusyBox v1.22.1 behaves in a similar way.
Under zsh, one can do
alias which="whence -p"
and get the same behavior, AFAIK.
> Another sidelight on zsh's behaviour illustrating the peculiarity of
> this case...
>
> % which true foo cat
> true: shell built-in command
> foo not found
> /bin/cat
>
> If "foo not found" went to stderr that would make the output overall a
> bit of a mess; it's not clear there's a good argument for complicating
> it like that. At least this looks to me like a good argument against
> changing it.
I agree. And I hardly see how the output from "which" (when it mean
"whence -c") can be useful in a script. If the user wants the pathname
to some command, he would need "whence -p".
--
Vincent Lefèvre <vincent@vinc17.net> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
next prev parent reply other threads:[~2015-09-02 14:00 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-30 3:06 Timo Buhrmester
2015-08-30 5:15 ` Bart Schaefer
2015-08-30 5:26 ` Timo Buhrmester
2015-09-01 6:04 ` Bart Schaefer
2015-09-01 6:12 ` Mikael Magnusson
2015-09-01 23:16 ` Bart Schaefer
2015-09-02 8:53 ` Peter Stephenson
2015-09-02 13:48 ` Vincent Lefevre [this message]
2015-09-01 13:14 ` Timo Buhrmester
2015-09-01 13:45 ` Peter Stephenson
2015-09-01 23:10 ` Bart Schaefer
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