Automatic Dynamics DNS updater using HTTP API calls, prepared for TwoDNS.de / Two-DNS.de (works with any other DDNS Service, allowing IP updates via HTTP API calls)

ddns_updater.sh

#!/bin/sh
log="ddns_updater.log.txt"
my_ext_ip=$(curl -sS http://icanhazip.com)
echo "\n\n\n===== \
   \n$(date -u) \
   \nUpdating IP to: $my_ext_ip \n" >> $log
curl -isSX PUT \
   -u "mail@host.tld:api_token" \
   -H "Content-Type: application/json" \
   --data '{"ip_address":"'$my_ext_ip'", "activate_wildcard": "false"}' \
   https://api.twodns.de/hosts/host.dynvpn.de >> $log
exit

Your suggestion is indeed very useful, thanks! Currently I have the script scheduled via Cron to fire it up periodically. To run it via nohup there would need to be some sort of loop and a waiting mechanism between the actions. And if I'm understanding it correctly if any changes to the script were to be made, the current nohup instance must be stopped and a new one needs to be started.