Setting up DNS according to OpenVPN dhcp-option (used with openvpn --up)

up.sh

#!/bin/sh
# Setting up DNS according to OpenVPN dhcp-option
# used with openvpn --up

mv /etc/resolv.conf /etc/resolv.conf.old

for (( i=1; 1; i++))
do
	optname="foreign_option_$i"
	option=${!optname}
	[ -n "$option" ] || break
	if [ -n `echo $option | grep DOMAIN` ] || [ -n `echo $option | grep DNS` ]
	then
		echo $option | sed -e 's/dhcp-option DOMAIN/search/g' -e 's/dhcp-option DNS/nameserver/g' >> /etc/resolv.conf
	fi
done

if [ -f /etc/resolv.conf ]
then
	cat /etc/resolv.conf
else
	mv /etc/resolv.conf.old /etc/resolv.conf
fi