#!/bin/sh

arg0="`basename $0`"	# base portion of our filename
arg1="$1"
tmpfile="/tmp/resolv.conf.$$"

usage ( ) {
	echo "usage: $arg0 -a|-r {ip} [{ip}...]"
	rm -f $tmpfile
	exit 1
}


[ "$#" -le 1 ] && usage

shift

cp /etc/resolv.conf $tmpfile

case "$arg1" in
	"-a")
		for ip in "$@"; do
		    echo $ip
			grep -sq "^nameserver $ip\$" $tmpfile || echo "nameserver $ip" >>$tmpfile
		done
	;;
	"-r")
		for ip in "$@"; do
			grep -v "^nameserver $ip\$" $tmpfile >$tmpfile.2
			mv $tmpfile.2 $tmpfile
		done
	;;
	*)
		usage
	;;
esac

[ -f $tmpfile ] && cp $tmpfile /etc/resolv.conf
rm -f $tmpfile

exit 0