Shell script to concurrent executing the other commands

parallel_commands.sh

#!/bin/sh
# ex: ./parallel_commands.sh 'echo test' 'echo test'

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

trap "kill $PID_LIST" SIGINT

echo "Parallel processes have started";

wait $PID_LIST

echo
echo "All processes have completed";