Get exit code of a background process

Question

I have a command CMD called from my main bourne shell script that takes forever.

I want to modify the script as follows:

1. Run the command CMD in parallel

Answer 1

Another solution is to monitor processes via the proc filesystem (safer than ps/grep combo); when you start a process it has a corresponding folder in /proc/$pid, so the solution could be

#!/bin/bash
....
doSomething &
local pid=$!
while [ -d /proc/$pid ]; do # While directory exists, the process is running
    doSomethingElse
    ....
else # when directory is removed from /proc, process has ended
    wait $pid
    local exit_status=$?
done
....

Now you can use the $exit_status variable however you like.