Portknocker

#!/bin/bash
ENM=$(which nmap)
if [ -z $ENM ];then
        printf "Requires nmap to be installed, aborting..\n"
fi
if [ ! $1 ];then
    printf "No arguments given\n"
else
    IP=$1
    shift
    for PORT in "$@"
    do
        nmap -Pn -p -n --max-retries 0 $PORT $HOST
    done
fi