From: Han Pingtian <hanpt@linux.vnet.ibm.com>
To: zsh-users@zsh.org
Cc: rahul <rahul2012@gmail.com>
Subject: Re: Capture stderr to variable without new process
Date: Wed, 23 Jan 2013 15:36:25 +0800 [thread overview]
Message-ID: <20130123073625.GA10056@localhost.localdomain> (raw)
In-Reply-To: <20130121233549.GA6494@redoubt.spodhuis.org>
On Mon, Jan 21, 2013 at 06:35:49PM -0500, Phil Pennock wrote:
> On 2013-01-22 at 01:41 +0530, rahul wrote:
> > I guess the typical way would be:
> >
> > ERR=$(popd 2>&1)
> >
> > However, the command cannot run in a sub-shell as it would have no effect
> > in the current shell.
> > Is writing to a file the only way ?
>
> If the output can only be one line and you have an unbuffered cat(1) (-u
> option).
>
> % coproc cat -u
> [1] 6550
> % popd 2>&p
> % read -p foo
> % echo $foo
> popd: directory stack empty
Good method. I think we can improve it by using a loop and add
a timeout to read:
% coproc cat
% git abc 2>&p
% while read -t 2 -p line;do ERR+=$line$'\n';done
% print "$ERR"
git: 'abc' is not a git command. See 'git --help'.
Did you mean this?
add
%
> % coproc -
This is interesting. How could we figure out this method, please?
>
> Otherwise, you need to script a cat-command which can exit on a sentinel
> line; I don't know of a way to close the coproc's stdin while leaving
> the coproc running to collect its output later. Perhaps someone else
> does? If you could send EOF on the coproc's stdin, then you could just
> use:
> popd_stderr="$(cat <&p)"
> after closing its stdin.
>
> -Phil
prev parent reply other threads:[~2013-01-23 7:37 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-21 20:11 rahul
2013-01-21 23:35 ` Phil Pennock
2013-01-23 7:36 ` Han Pingtian [this message]
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