Trying to capture stdout of background process in bash script - bash

Question

I wrote the following to be used with Jenkins to kick off my selenium tests. Now since they are being executed as background processes, when they fail Jenkins believes they haven't. As you can see my futile attempt on making this work. Any ideas? Thought about piping the output into a file and grepping for keywords. Then I realized I don't know how to reflect an error if a grep for string returns true.
#!/bin/bash
FAIL=0
echo "starting"
ruby /root/selenium-tests/test/test1.rb &
ruby /root/selenium-tests/test/test2.rb &
ruby /root/selenium-tests/test/test3.rb &
#wait
for job in `jobs -p`
do
echo $job
wait $job || let "FAIL+=1"
done
echo $FAIL
if [ "$FAIL" == "0" ];
then
echo "PASS"
else
echo "FAIL! ($FAIL)"
fi

Answer 1

Jenkins most likely looks at the process exit code to determine whether tests fails. This is what all Unix tools do.
There are multiple ways of doing this. If your test files output something like "FAIL" instead of properly returning an exit code, you can do:
#!/bin/bash
(
ruby /root/selenium-tests/test/test1.rb &
ruby /root/selenium-tests/test/test2.rb &
ruby /root/selenium-tests/test/test3.rb &
wait
) > log
! grep "FAIL" log
exit $? # <- happens implicitly at the end of the script, and can be left out
In this case, grep finding "FAIL" will cause the script to fail, and Jenkins to detect the failure.
The more correct way, if your scripts return proper exit codes, is your method but without relying on job control (which by default is turned off in non-interactive shells), and returning correct exit codes:
for test in /root/selenium-tests/test/test*.rb
do
ruby "$test" &
pids+=( $! )
done
for pid in "${pids[#]}"
do
if wait $pid
then
echo "$pid succeeded"
else
echo "$pid failed"
(( failures++ ))
fi
done
if [[ $failures -gt 0 ]]
then
echo "FAIL: $failures failed tests"
exit 1 # return failure
else
echo "PASS!"
exit 0 # return success
fi