pkill

#!/bin/sh
# Kill the tasks using a specified localhost port.

if	[ -z "$1" ]
    then
        echo "Specify a port to kill.";
        return 1; #exit function
    else
        pid=`lsof -i -P | grep $1 | tr -s ' ' | cut -d ' ' -f 2 | sort --unique`;
        echo $pid;
        if	[ -z "$pid" ]
            then
                echo "No PIDs were using port $1.";
            else
                kill -9 $pid;
                echo "PIDs using port $1 have been killed.";
        fi
fi