How to run script on startup on Ubuntu 20.04 Focal Fossa Server/Desktop - LinuxConfig.org

In this article you will learn how to run script ( python, bash etc. ) on startup on Ubuntu 20.04 Server/Desktop
This is a companion discussion topic for the original entry at https://linuxconfig.org/how-to-run-script-on-startup-on-ubuntu-20-04-focal-fossa-server-desktop