Basic nslookup loop script for Linux

nslookup.sh

#!/bin/sh
for IP in `cat ./ips.txt`
do
  printf "$IP\t"
	LOOKUP_RES=`nslookup $IP`
	FAIL_COUNT=`echo $LOOKUP_RES | grep "** server can't find " | wc -l`;
	if [ $FAIL_COUNT -eq 1 ]
	then
		NAME='Bad FQDNS\n';
	else
		NAME=`echo $LOOKUP_RES | grep -v nameserver | cut -f 2 | grep name | cut -f 2 -d "=" | sed 's/ //'`;
	fi
	echo $NAME
done

# one-liner
$ for i in `cat urls.txt`; do nslookup $i 2>/dev/null | grep Address | tail -n 1 | cut -d " " -f 3; done > ips.txt