Execute command in multiple directories in parallel

exec.sh

#!/bin/bash

# example: run puppet tests in all modules
CMD="pdk test unit --format=junit:report.xml &> pdk_test.log"

for d in $(ls -d); do {
  cd $d
  $CMD & pid=$!
  PID_LIST+=" $pid";
  cd ..
} done

trap "kill $PID_LIST" SIGINT

echo "Parallel processes have started";

wait $PID_LIST