#!/bin/sh

if [ $# -eq 0 ]; then
    currentFile=$(basename "$0")
    echo "Usage: ./$currentFile <dns_ip>"
    exit 0
fi

# add users dns preference to the beginning of /etc/resolv.conf
cp /etc/resolv.conf /tmp/resolv.conf.bak
echo "nameserver $1" > /etc/resolv.conf
cat /tmp/resolv.conf.bak >> /etc/resolv.conf