Get-default-interface.sh

#!/bin/bash

default_route_gateway=$(/sbin/ip route list match 0.0.0.0/0 | awk '{print $3 }')
echo "Default route gateway: ${default_route_gateway}"

interface_that_services_the_default_route_gateway=$(/sbin/ip route get to ${default_route_gateway} | awk '{print $3}')
echo "The interface that services the default route gateway: ${interface_that_services_the_default_route_gateway}"

default_interface_ip=$(/sbin/ip route get to ${default_route_gateway} | awk '{print $5}')
echo "Default interface IP: ${default_interface_ip}"