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Re: lastpipe and "*may* be run by the shell process"
From: |
Andreas Kusalananda Kähäri |
Subject: |
Re: lastpipe and "*may* be run by the shell process" |
Date: |
Tue, 12 May 2020 00:03:21 +0200 |
On Mon, May 11, 2020 at 04:57:16PM -0400, Chet Ramey wrote:
> On 5/11/20 3:15 PM, Andreas Kusalananda Kähäri wrote:
> > Hi,
> >
> > I was recently answering a bash-related query in another context, and
> > found myself quoting the bash (5.0.17(1)-release) manual:
> >
> > Each command in a pipeline is executed as a separate
> > process (i.e., in a subshell). See COMMAND EXECUTION
> > ENVIRONMENT for a description of a subshell environment.
> > If the lastpipe option is enabled using the shopt
> > builtin (see the description of shopt below), the last
> > element of a pipeline may be run by the shell process.
> >
> > What caught my eye was the word "may" in the last sentence, and it
> > struck me that I couldn't immediately think of a case where this word
> > couldn't be "will" instead. That is to say, where setting the lastpipe
> > shell option did *not* cause the last part of a pipeline to run in the
> > invoking shell environment.
>
> If job control is enabled.
So it is, and so it says later in the manual. Duh. I should go to bed.
Thanks! And sorry for the noise.
--
Andreas (Kusalananda) Kähäri
SciLifeLab, NBIS, ICM
Uppsala University, Sweden
.