From: Bart Schaefer <schaefer@brasslantern.com>
To: Zsh hackers list <zsh-workers@zsh.org>
Subject: Re: $PPID not updated when the PPID changes (parent killed)
Date: Mon, 17 May 2021 16:15:24 -0700 [thread overview]
Message-ID: <CAH+w=7bywj1X1fyPLgpmo_OoqBEN8PjEDxDeKP-tMR_O4g04tg@mail.gmail.com> (raw)
In-Reply-To: <YKLttAsFd4bl9waS@fullerene.field.pennock-tech.net>
On Mon, May 17, 2021 at 3:27 PM Phil Pennock
<zsh-workers+phil.pennock@spodhuis.org> wrote:
>
> The initial parent process ID; that is, the process ID of the process
> which created this shell process, at the time that it did so.
This is pretty close to what I was thinking. Does "at the time"
really add anything?
> Just as for $$, the value is only set for the original shell and does
> not dynamically change for implicit subshells (as created for (list)
> and for pipelines).
Except (list) is an explicit subshell, isn't it?
> It's an attempt to be clearer that "if you run zsh within zsh,
> that's not a subshell, sure _that_ gets $$ and $PPID reset".
Indeed. I'm tempted to say
Just as with $$, the value is updated only within a new shell
that increases $SHLVL, and not in other subshells.
And then clarify "a new shell" under SHLVL if necessary, but I hope it isn't.
Aside, it's a bit odd that SHLVL isn't read-only. Even assorted Bash
tutorials found by online search treat it as immutable (statements
like "$dog is only available at SHLVL 2") despite that it can be
arbitrarily messed with.
next prev parent reply other threads:[~2021-05-17 23:15 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-16 15:24 Vincent Lefevre
2021-05-16 18:37 ` Bart Schaefer
2021-05-17 20:26 ` Vincent Lefevre
2021-05-17 21:00 ` Bart Schaefer
2021-05-17 22:27 ` Phil Pennock
2021-05-17 23:15 ` Bart Schaefer [this message]
2021-05-18 0:30 ` Phil Pennock
2021-05-18 1:14 ` Bart Schaefer
2021-05-18 8:28 ` Vincent Lefevre
2021-05-18 8:15 ` Vincent Lefevre
2021-05-18 14:53 ` Bart Schaefer
2021-05-19 4:25 ` Bart Schaefer
2021-07-18 23:10 ` Lawrence Velázquez
2021-05-18 15:18 ` Mikael Magnusson
2021-05-18 16:14 ` Peter Stephenson
2021-05-18 18:20 ` Bart Schaefer
2021-05-18 17:37 ` Martijn Dekker
2021-05-18 18:08 ` Bart Schaefer
2021-05-18 19:40 ` Martijn Dekker
2021-05-18 18:06 ` Stephane Chazelas
2021-05-18 18:12 ` Bart Schaefer
2021-05-18 18:50 ` $SHLVL origin (was: $PPID not updated when the PPID changes (parent killed)) Stephane Chazelas
2021-05-18 15:56 ` $PPID not updated when the PPID changes (parent killed) Stephane Chazelas
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