DDNS client for namecheap with systemd init script

gist-update-ddns.sh

#!/bin/bash
# update namecheap ddns from unraid
# 2020-01-06 

# systemd init script:

# [Unit]
# Description=Updates internal DDNS for meowth.kanto.blue
# After=network.target
#
# [Service]
# Restart=always
# RestartSec=5
# ExecStart=/path/to/update-ddns.sh
#
# [Install]
# WantedBy=default.target

HOSTNAME=<subdomain>
DOMAIN=<yourdomain.com>
PASSWORD=<namecheapDDNSkey>
INTERFACE='enp2s0'

while true; do
	touch "${HOME}/.ddns"
	LASTIP="$(cat "${HOME}/.ddns")"
	IP="$(ip addr show $INTERFACE | grep -Po 'inet \K[\d.]+')"

	if [[ "$LASTIP" != "$IP" ]]; then
	  if curl -s "https://dynamicdns.park-your-domain.com/update?host=$HOSTNAME&domain=$DOMAIN&password=$PASSWORD&ip=$IP" | grep '<ErrCount>0</ErrCount>'; then
	    echo "$IP" > "${HOME}/.ddns"
	    echo "[+] DDNS: $IP"
	  else
	    echo "[-] Failed to update DDNS"
	  fi
	fi

	sleep 5

done

exit 1