Linux Shell script to find the process listening on a given port

port=$1
procinfo=$(netstat --numeric-ports -nlp 2> /dev/null grep ^tcp grep -w ${port} tail -n 1 awk '{print $7}')
case "${procinfo}" in
"")
echo "No process listening on port ${port}"
;;
"-")
echo "Process is running on ${port}, but current user does not have rights to see process information."
;;
*)
echo "${procinfo} is running on port ${port}"
ps -uwep ${procinfo%%/*}
;;
esac