run commands in parallel with exit fail if any command fails

Question

Need help in a bash script. The goal is: - Run several commands in parallel - Exit 1 if any command return not-zero exit status

I.e.

Run with middle command has error:

$ ./parallel_commands "echo 1" "_echo 2" "echo 3" && echo "OK"
1
3
./parallel_commands: line 4: _echo: command not found
OK <- Incorrect

Run with all commands have errors:

$ ./parallel_commands "_echo 1" "_echo 2" "_echo 3" && echo "OK"
./parallel_commands: line 4: _echo: command not found
./parallel_commands: line 4: _echo: command not found
./parallel_commands: line 4: _echo: command not found
-> Result is fail -> Correct

Bash script:

#!/bin/bash

for cmd in "$@"; do {
  $cmd & pid=$!
  PID_LIST+=" $pid";
} done

trap "kill $PID_LIST" SIGINT

wait $PID_LIST

Thanks.

Answer 1

You are probably looking for something like this using GNU Parallel:

parallel ::: "echo 1" "_echo 2" "echo 3" && echo OK

GNU Parallel is a general parallelizer and makes is easy to run jobs in parallel on the same machine or on multiple machines you have ssh access to.

If you have 32 different jobs you want to run on 4 CPUs, a straight forward way to parallelize is to run 8 jobs on each CPU:

GNU Parallel instead spawns a new process when one finishes - keeping the CPUs active and thus saving time:

Installation

If GNU Parallel is not packaged for your distribution, you can do a personal installation, which does not require root access. It can be done in 10 seconds by doing this:

(wget -O - pi.dk/3 || curl pi.dk/3/ || fetch -o - http://pi.dk/3) | bash

For other installation options see http://git.savannah.gnu.org/cgit/parallel.git/tree/README

Learn more

See more examples: http://www.gnu.org/software/parallel/man.html

Watch the intro videos: https://www.youtube.com/playlist?list=PL284C9FF2488BC6D1

Walk through the tutorial: http://www.gnu.org/software/parallel/parallel_tutorial.html

Sign up for the email list to get support: https://lists.gnu.org/mailman/listinfo/parallel