Bash script to add a line to osx hosts file

mac-addhost.sh

#!/bin/sh

ETC_HOSTS=/etc/hosts

IP="xx.xx.xx.xx"
HOSTNAME="www.domain.com"

HOSTS_LINE="$IP\t$HOSTNAME"
if [ -n "$(grep $HOSTNAME /etc/hosts)" ]
    then
        echo "$HOSTNAME already exists : $(grep $HOSTNAME $ETC_HOSTS)"
    else
        echo "Adding $HOSTNAME to your $ETC_HOSTS";
        sudo -- sh -c -e "echo '$HOSTS_LINE' >> /etc/hosts";

        if [ -n "$(grep $HOSTNAME /etc/hosts)" ]
            then
                echo "$HOSTNAME was added succesfully \n $(grep $HOSTNAME /etc/hosts)";
            else
                echo "Failed to Add $HOSTNAME, Try again!";
        fi
fi