Asking grep to output stuff and the piping it to /dev/null can be done
better, use "grep -q".

From man grep:
    -q, --quiet, --silent
              Quiet; do not write anything to standard output.
              Exit immediately with zero status if any match is found,
              even if  an  error was detected.
              Also see the -s or --no-messages option.

While there, remove the redirection of stderr.
It should be quiet anyway, and if there really is an error,
we want to see it.
This removes the "bash-istic" "&> /dev/null"
which is a non-portable version of >/dev/null 2>&1