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From: Roman Perepelitsa <roman.perepelitsa@gmail.com>
To: Sebastian Gniazdowski <sgniazdowski@gmail.com>
Cc: Zsh hackers list <zsh-workers@zsh.org>
Subject: Re: Effect of different sublist execution?
Date: Tue, 14 Mar 2023 12:15:23 +0100	[thread overview]
Message-ID: <CAN=4vMr-=X8LDF1vi4-CzZEEckL6SeyNzioVS1oc5A_qLZxF4A@mail.gmail.com> (raw)
In-Reply-To: <CAKc7PVD9GtnToYyCD6BJhgGraagDZCYOXYNcCUcMHqYxEL+bgQ@mail.gmail.com>

On Tue, Mar 14, 2023 at 12:07 PM Sebastian Gniazdowski
<sgniazdowski@gmail.com> wrote:
> Doc say:
> If a sublist is terminated by a `&',
> `&|', or `&!', the shell executes the last pipeline in it in the  back‐
> ground,  and  does  not wait for it to finish (note the difference from
> other shells which execute the whole sublist  in  the  background).
> I wonder about presenting this via some real effect. How to show that
> only the last pipeline is running in background (like the doc say)
> when sublist/pipeline is ended via &? I'm looking for a snippet that
> will behave differently for the two cases: sublist &-ended and ;-ended

You can try this:

    sleep 5 && true &

In zsh this code will block for 5 while in bash it'll execute
instantly. You can confirm that zsh executes the first part of the
sublist without forking with this code:

    % zmodload zsh/system
    % print $sysparams[pid]
    % print $sysparams[pid] && true &


      reply	other threads:[~2023-03-14 11:15 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-14 11:06 Sebastian Gniazdowski
2023-03-14 11:15 ` Roman Perepelitsa [this message]

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