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

#/bin/bash

#pgm to monitor
tail -f /var/log/messages >> /tmp/log&
# background cmd pid
pid=$!
# loop to monitor running background cmd
while :
do
    ps ax | grep $pid | grep -v grep
    ret=$?
    if test "$ret" != "0"
    then
        echo "Monitored pid ended"
        break
    fi
    sleep 5

done

wait $pid
echo $?