Compound commands in && / || condition

Question

I know this is a common question and I have even seen answers to it before, but I cannot remember what they were nor find them.

#!/usr/bin/env bash

set -m         # allow for job control
EXIT_CODE=0    # exit code of overall script

function foo() {     
     for job in `jobs -p`; do
         echo "PID => ${job}"
         wait ${job} ||  { echo "At least one test failed with exit code => $?" ; EXIT_CODE=1; }
     done
}

trap 'foo' CHLD

My question concerns this line:

wait ${job} ||  { echo "At least one test failed with exit code => $?" ; EXIT_CODE=1; }

If wait ${job} yields a non-zero exit code I'd like to echo out the statement and then do an assignment (assigning 1 to EXIT_CODE).

I don't believe my syntax is correct. I am not getting any obvious errors, but I am pretty certain it's not correct because the statement is not being echoed. But I am still exiting with an exit code of 1.

That wait... line already looks good to me. I assume you've not provided your entire script, though, so there's only the posted context to review. — Chris Davies
– Chris Davies, Commented Feb 13, 2017 at 13:07

Andy Dalton · Accepted Answer · 2017-02-13 21:40:40Z

Are you sure that wait is terminating with a non-zero exit status? Consider, for example:

false || { echo "At least ..."; EXIT_CODE=1; }

That will generate the message and set EXIT_CODE appropriately.

I initially thought this was what you were looking for:

wait ${job} || ( echo "At least ..."; EXIT_CODE=1 )

The problem with this approach is that the content of (...) is executed in a subshell – the change to the value of EXIT_CODE will be local to that subshell (i.e., it won't be visible when you try to read it later).

Consider, for example:

EXIT_CODE=0
false || ( echo "At least ..." ; EXIT_CODE=1; echo "code: ${EXIT_CODE}" )
echo "final code: ${EXIT_CODE}"

The output will be:

At least ...
code: 1
final code: 0

I'd suggest not trying to be too fancy:

if ! wait ${job}; then
    echo "At least ..."
    EXIT_CODE=1;
fi

should it be if [[ ! wait ${job} ]] ; then

Alexander Mills
– Alexander Mills

2017-02-14 00:31:58 +00:00
Commented Feb 14, 2017 at 0:31 — Alexander Mills
– Alexander Mills, Commented Feb 14, 2017 at 0:31

Stack Exchange Network

Compound commands in && / || condition

1 Answer 1

You must log in to answer this question.

Hot Network Questions

Compound commands in && / || condition

1 Answer 1

You must log in to answer this question.

Related

Hot Network Questions