checkport - check if one or more TCP ports are opened

checkport.sh

#!/bin/bash
 #
 # Created by: Matteo Gaggiano on 22/04/2017
 # Base script by: stojg at https://gist.github.com/stojg/70a15a84900da72ff2b5
 #
 # Changelog 22/04/2017 :
 #     - Added support for multi-port check
 #
 
function usage() {
  echo "Usage: $0 host port1 [port2 [port3] ... ]"
}

function _checkport() {
  if nc -zv -w30 $1 $2 <<< '' &> /dev/null
  then
    echo "[+] Port $1/$2 is open"
  else
    echo "[-] Port $1/$2 is closed"
  fi
}

function main() {
  for port in ${@:1}
  do
    _checkport $1 $port
  done
}

[ $# -lt 2 ] && (usage $0 && exit 1) || main $1 ${@:2}