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Date: Tue, 12 Aug 2008 17:40:59 +0200
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Cc: Dmitry Semyonov <linulin AT gmail DOT com>
Subject: Re: ash-20040127-3: Invalid behavior of negated pipeline
Message-ID: <20080812154059.GS5129@calimero.vinschen.de>
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On Aug 12 19:36, Dmitry Semyonov wrote:
> Hello all,
> 
>  -- begin --
> $ bash -c '! true | false; echo $?'
> 0
> 
> $ ash -c '! true | false; echo $?'
> 1
>  -- end --
> 
> Mostly "if" conditions are affected by this issue.
> 
> Quote[1] from the "Shell Command Language" standard: "If the reserved
> word ! does not precede the pipeline, the exit status shall be the
> exit status of the last command specified in the pipeline. Otherwise,
> the exit status shall be the logical NOT of the exit status of the
> last command. That is, if the last command returns zero, the exit
> status shall be 1; if the last command returns greater than zero, the
> exit status shall be zero."
> 
> [1] http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_09_02
> 
> 
> So, in this particular case, ash is not compliant with the standard,
> nor it is compatible with bash or dash (Debian ash derivative).

Use bash as sh.  ash is only in the distro to run rebaseall.  I won't
release a new version of ash any time soon, if it doesn't explicitely
affect rebase.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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