From: Bart Schaefer <schaefer@brasslantern.com>
To: Ray Andrews <rayandrews@eastlink.ca>
Cc: Zsh Users <zsh-users@zsh.org>
Subject: Re: detect pipe
Date: Wed, 27 Jan 2021 15:59:20 -0800 [thread overview]
Message-ID: <CAH+w=7b=OmLb7+cbr0uFSgKay6yJksfbWyxD5WAVjXrrq3RAMw@mail.gmail.com> (raw)
In-Reply-To: <e7dc936d-4149-7882-5ac9-24e34b268985@eastlink.ca>
On Wed, Jan 27, 2021 at 8:45 AM Ray Andrews <rayandrews@eastlink.ca> wrote:
>
> I have a function that as used this test for piping quite reliably:
>
> if [ ! -t 0 ]; then
>
> ... but today it stopped working.
[ -t 0 ] or [[ -t 0 ]] mean that the standard input is a terminal.
It's quite possible for standard input to be neither a terminal (so [[
! -t 0 ]] is true) nor a pipe. For example, redirection from a file
or use of a here-document will both take the then-branch of "if [[ !
-t 0 ]]; then ... else ... fi".
> there a better way? This is probably not strictly a zsh problem but the
> randomness of it working intermittently suggests some time lag or delay
A race condition would be unlikely to be a cause here.
[[ -p /dev/fd/0 ]] would be a more reliable test, because of the way
conditional expressions special case the prefix "/dev/fd/".
next prev parent reply other threads:[~2021-01-28 0:00 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-27 16:45 Ray Andrews
2021-01-27 23:59 ` Bart Schaefer [this message]
2021-01-28 4:57 ` Ray Andrews
2021-01-28 6:16 ` Bart Schaefer
2021-01-28 10:08 ` Vincent Lefevre
2021-01-28 10:28 ` Vincent Lefevre
2021-01-28 15:05 ` Ray Andrews
2021-01-28 15:45 ` Ray Andrews
2021-01-28 20:58 ` Bart Schaefer
2021-01-28 20:59 ` Bart Schaefer
2021-01-29 1:17 ` Ray Andrews
2021-01-29 2:50 ` Bart Schaefer
2021-01-29 3:21 ` Ray Andrews
2021-01-30 0:29 ` Bart Schaefer
2021-01-30 14:26 ` Ray Andrews
2021-01-30 19:00 ` Bart Schaefer
2021-01-30 19:19 ` Ray Andrews
2021-01-31 19:12 ` Ray Andrews
2021-01-31 21:28 ` Bart Schaefer
2021-02-14 17:31 ` Vincent Lefevre
2021-02-14 19:33 ` Bart Schaefer
2021-02-14 20:33 ` Ray Andrews
2021-02-14 21:20 ` Bart Schaefer
2021-02-14 22:25 ` Ray Andrews
2021-02-14 21:24 ` Vincent Lefevre
2021-02-14 21:19 ` Vincent Lefevre
2021-02-14 21:24 ` Bart Schaefer
2021-02-14 21:38 ` Bart Schaefer
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