#!/usr/bin/env bash

interface="${MADD_INTERFACE:-"eth0"}"
client_script="${MADD_CLIENT_SCRIPT:-"./client.sh"}"

ip monitor address label dev "$interface" | while read event; do
    if [[ $event == \[ADDR\]* ]]; then
        ipv4=$(ip addr show dev "$interface" | grep -Po 'inet \K[\d.]+')
        if [ -n "$ipv4" ]; then
            export MADD_IP="$ipv4"
            $client_script
        fi
    fi
done