destroyByPort.sh

#!/bin/bash
if [ -z "$1" ]; then
  echo "Error: No argument passed" >&2; exit 1
fi

if ! [[ $1 =~ ^[0-9]+$ ]] ; then
  echo "Error: Argument is not a number" >&2; exit 1
fi

PIDToKill=$(lsof -i:$1 | grep LISTEN | awk '{print $2}' | uniq)

if [ -z "$PIDToKill" ]; then
  echo "Error: No process listening on port ${1} found" >&2; exit 1
fi

{
  kill -9 $PIDToKill
  echo "Successfully killed process with PID ${PIDToKill} listening on port ${1}"; exit 1
} || {
  echo "Error: unknown error when tried to kill process ${PIDToKill}" >&2; exit 1
}