After each command, the exit code can be found in the $?
variable so you would have something like:
ls -al file.ext
rc=$?; if [[ $rc != 0 ]]; then exit $rc; fi
You need to be careful of piped commands since the $?
only gives you the return code of the last element in the pipe so, in the code:
ls -al file.ext | sed 's/^/xx: /"
will not return an error code if the file doesn't exist (since the sed
part of the pipeline actually works, returning 0).
The bash
shell actually provides an array which can assist in that case, that being PIPESTATUS
. This array has one element for each of the pipeline components, that you can access individually like ${PIPESTATUS[0]}
:
pax> false | true ; echo ${PIPESTATUS[0]}
1
Note that this is getting you the result of the false
command, not the entire pipeline. You can also get the entire list to process as you see fit:
pax> false | true | false; echo ${PIPESTATUS[*]}
1 0 1
If you wanted to get the largest error code from a pipeline, you could use something like:
true | true | false | true | false
rcs=${PIPESTATUS[*]}; rc=0; for i in ${rcs}; do rc=$(($i > $rc ? $i : $rc)); done
echo $rc
This goes through each of the PIPESTATUS
elements in turn, storing it in rc
if it was greater than the previous rc
value.
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