OpenVPN disconnect and restore DNS config

#!/bin/sh -e

script_dir="`dirname $0`"
vpnpidfile="openvpn.pid"

if ! cd $script_dir ; then
    echo "Cannot cd to $script_dir." 1>&2
    exit 1
fi

vpnpid=`cat $vpnpidfile`

sudo kill -INT $vpnpid

# Restore DNS
sudo resolvconf -u