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Date:      Mon, 3 Dec 2012 11:30:45 -0500
From:      Jerry <jerry@seibercom.net>
To:        FreeBSD <freebsd-questions@freebsd.org>
Subject:   Re: bash pipe redirection gets stuck
Message-ID:  <20121203113045.02972ed0@scorpio>
In-Reply-To: <23353.144.36.114.84.1354545315.squirrel@mail.rule.lv>
References:  <23353.144.36.114.84.1354545315.squirrel@mail.rule.lv>

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On Mon, 3 Dec 2012 16:35:15 +0200 (EET)
long@rule.lv articulated:

> Dear all,
> I stumbled upon a problem where multiple pipe redirection
> occasionally get stuck when trying to get sha256 sum of a stream.
> 
> You can try to reproduce the problem if you
> have /usr/ports/shells/bash installed (output redirection used in
> this command is possible only in bash).
> Create temporary test file with command: "dd if=/dev/urandom
> of=/tmp/file1 bs=1k count=10"
> And the command I'm using is:
> /usr/local/bin/bash -c 'cat /tmp/file1 | tee >(/sbin/sha256 >
> /tmp/file1.sha256) > /tmp/file1.copy' ; echo $status
> 
> Command gets stuck about once in 20 executions.
> top output when command gets stuck (irrelevant processes removed):
>   PID USERNAME    THR PRI NICE   SIZE    RES STATE   C   TIME   WCPU
> COMMAND 84073 HappyUser     1  52    0 17612K  2268K wait    0
> 0:00  0.00% bash 84154 HappyUser     1  52    0 10084K   844K fifoow
> 1   0:00  0.00% tee
> 
> And more strangely, I can reproduce this problem on 9.0-RELEASE and
> 7.4-RELEASE-p6, but couldn't reproduce on 8.2-RELEASE-p4.
> 
> Thanks for any pointers/explanations,
> Normunds

For starters, what version of Bash? FreeBSD is still a few patches
behind the current patch level, so that is also a possibility.

I would suggest you visit:
<https://lists.gnu.org/mailman/listinfo/bug-bash>, subscribe to the
list and then ask your question <bug-bash@gnu.org>.

-- 
Jerry ♔

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