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From: Jilles Tjoelker <jilles@stack.nl>
To: Jonathan Nieder <jrnieder@gmail.com>
Cc: Michael Welsh Duggan <mwd@cert.org>, dash@vger.kernel.org
Subject: Re: Question about job control in non-interactive shells
Date: Fri, 13 Jan 2012 16:49:26 +0100	[thread overview]
Message-ID: <20120113154926.GA42715@stack.nl> (raw)
In-Reply-To: <20120109163745.GA23825@burratino>

On Mon, Jan 09, 2012 at 10:37:45AM -0600, Jonathan Nieder wrote:
> Michael Welsh Duggan wrote:
> > I am trying to determine why:

> >   dash -c "sleep 5 & kill %1"

> > results in:

> >   dash: 1: kill: No such process

> You are probably looking for the -m option.

The cause is that the -m option ("job control") enables running commands
in separate process groups, and dash follows literally what POSIX says
about kill %job: a background process group should be signaled; however,
there is no background process group. Some shells signal one or more
processes they know are part of the job in this case, but dash calls
kill() on a process group that is guaranteed not to exist.

-- 
Jilles Tjoelker

  reply	other threads:[~2012-01-13 16:00 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-09 16:17 Question about job control in non-interactive shells Michael Welsh Duggan
2012-01-09 16:37 ` Jonathan Nieder
2012-01-13 15:49   ` Jilles Tjoelker [this message]
2012-01-15  3:53     ` Herbert Xu

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