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(Created page with '== Tips / How-To == === Get status of a pipe === In CSH (and Bash), <code>$status</code> returns the status of the last process in a pipe (actually this is only true for Bash; fo…') |
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status=`((ls /FOO ; echo $? > &4) | sed 1,1d 1>&3) 4>&1` |
status=`((ls /FOO ; echo $? > &4) | sed 1,1d 1>&3) 4>&1` |
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exit $status |
exit $status |
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</source> |
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Another variant for ''ksh'' here (from [http://www.unix.com/unix-dummies-questions-answers/13018-exit-status-command-pipe-line.html]): |
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<source lang=bash> |
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#! /usr/bin/ksh |
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exec 4>&1 |
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tail -5 >&4 |& |
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exec >&p |
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cat /etc/passwd |
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exitcode=$? |
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exec >&- >&4 |
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wait |
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echo exitcode = $exitcode |
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exit 0 |
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</source> |
</source> |
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Revision as of 00:33, 14 March 2013
Tips / How-To
Get status of a pipe
In CSH (and Bash), $status returns the status of the last process in a pipe (actually this is only true for Bash; for csh, it returns the status of the process that exited last!)
foo | bar
echo $status # Print status of bar, not foo!
To still get the status of process foo, one has to use extra named pipe to carry on the information (see [1])
exec 3>&1
status=`((ls /FOO ; echo $? > &4) | sed 1,1d 1>&3) 4>&1`
exit $status
Another variant for ksh here (from [2]):
#! /usr/bin/ksh
exec 4>&1
tail -5 >&4 |&
exec >&p
cat /etc/passwd
exitcode=$?
exec >&- >&4
wait
echo exitcode = $exitcode
exit 0