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From: Stephane Chazelas <stephane@chazelas.org>
To: Bart Schaefer <schaefer@brasslantern.com>
Cc: Zsh hackers list <zsh-workers@zsh.org>
Subject: Re: Suggested changes to Etc/FAQ
Date: Mon, 13 Nov 2023 07:13:38 +0000	[thread overview]
Message-ID: <2da3cd0f2900d052239dc94dc5b2dc44@chazelas.org> (raw)
In-Reply-To: <CAH+w=7YxP-5fZEdsBEvJXC9X1FVOv=v1z88MC2D1G5xDJQh0aA@mail.gmail.com>

About that:

> In cmd1 && cmd2 &, only cmd2 instead of the whole expression
> is run in the background in zsh. The manual implies this is
> a bug. Use { cmd1 && cmd2 } & as a workaround.

And in particular the "The manual implies this is a bug".

That section was added to the FAQ in October 1997. At the time, the 
manual had:

>  If a sublist is terminated
> by a `tt(&)', `tt(&|)', or `tt(&!)',
> the shell executes it in the background, and
> does not wait for it to finish.

But that was later (2000: 
https://github.com/zsh-users/zsh/commit/ed8b82b9b1bf74392caf4f4683f367bc4cbbd193#diff-6a204419ff23048734de2793d1072ec031dcdcd08aeb14cf75c14ec953835bddL68)
changed to what we have today:

> If a sublist is terminated by
> a '&', '&|', or '&!', the shell executes the last pipeline in it in the
> background, and does not wait for it to finish (note the difference 
> from
> other shells which execute the whole sublist in the background)

So that's no longer considered as a bug but works as documented.

So that "The manual implies this is a bug" should be removed I'd think 
or
maybe replaced by something that notes that it was not originally 
intentional.

{ cmd1 && cmd2 } & might be better as (cmd1 && cmd2) & so it's portable 
to
other shells and makes it more evident that that runs in a subshell.

-- 
Stephane


  reply	other threads:[~2023-11-13  7:14 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-11  5:10 Bart Schaefer
2023-11-11 11:59 ` Stephane Chazelas
2023-11-11 21:51   ` Bart Schaefer
2023-11-13  7:13     ` Stephane Chazelas [this message]
2023-11-13 14:18 ` Peter Stephenson
2023-11-16  2:32   ` Bart Schaefer

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