#!/bin/sh

function arp {
        printf "$(cat /proc/net/arp)"
}

gateway_ip="$(ip route | grep default | awk '{print $3}')"
ping -c 1 "$gateway_ip" -W 1 &> /dev/null
gateway_mac="$(arp | grep -w "$gateway_ip" | awk '{print $4}')"

echo "$gateway_mac"