#!/bin/bash
# Usage: checkzone NS_SERVER DOMAIN SERIAL_NUMBER
for i in $*
do
  if [ "$i" = "--help" ]
  then
    echo "Usage: checkzone NS_SERVER DOMAIN SERIAL_NUMBER"
    exit
  fi
done

while true
do
	var_host=`dig @$1 SOA $2 | grep SOA | grep -v ";" | awk '{print $7}'`
	if [ "$var_host" = "$3" ]
	then
		echo "Server was updated."
		echo $var_host
		break
	fi

	sleep 60
done