timeout for child process with its exit code

timeout.sh

#!/bin/sh

timeout() {
  # Spawn a child process:
  ($1) & pid=$!
  # in the background, sleep for x secs then kill that process
  (sleep ${2:-'10'} && kill -9 $pid) & waiter=$!
  # wait on our worker process and return the exitcode
  wait $pid && exit_code=$?
  # kill the waiter subshell, if it still runs
  kill -9 $waiter 2>/dev/null
  # 0 if we killed the waiter, cause that means the process finished before the waiter
  finished_gracefully=$?
  if [ "$exit_code" == "0" ]; then exit $finished_gracefully; fi
  exit 1
}

timeout "$@"

# Usage
# timeout "<your command>" [<number_of_seconds_for_timeout>=10]
# timeout "./my-shell-script.sh" 20