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Date: Tue, 12 Aug 2008 19:36:13 +0400
From: "Dmitry Semyonov" <linulin AT gmail DOT com>
To: cygwin AT cygwin DOT com
Subject: ash-20040127-3: Invalid behavior of negated pipeline
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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).


P.S.
$ cygcheck -c ash bash
Cygwin Package Information
Package              Version        Status
ash                  20040127-3     OK
bash                 3.2.39-20      OK

P.P.S.
Please, CC me. I'm not on the list.

-- 
...Bye..Dmitry.

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