I logged into find my disk to full to use. Why didn’t it tell me? Here are my notes.
Is Twitter the answer, or should I use mail/smtp or even snmp?

Twitter

1. How to tweet from the Linux command line from ostechnix

Mail

1. How to setup email alerts on linux using gmail from “How to Geek”
2. How to set up a mail server on your Raspberry Pi? from Raspberry Tips
3. See my little mail server

SNMP

1. raspberry pi SNMP from bytes of gigabytes, how to install on the PI
2. Free SNMP console for Android from Manage Engine
3. Monitoring The Raspberry Pi with MRTG from satsignal.eu, focused on the monitored device
4. The Multi Router Traffic Grapher at wikipedia
5. https://pushover.net/, a free trial but otherwise $5 per annum, looks like a console. Maybe free for individual use. It has some code examples here, inc. the command line.
6. https://simplepush.io/#about is this another tool at the console end

Others?

1. https://grafana.com/
2. Is IFTTT, part of the answer, using RSS as the event log? Or Monitoro.