HISTORICAL INTEREST ONLY
Livia's fork at https://github.com/livialima/linuxupskillchallenge is now where the action happens.
Introduction to Linux Server Administration!
This includes all the source material for the 20 lessons of what was previously a commercial online Linux server admin course - now free for you to learn with! (If you spot any typos or "dead links" simply raise a GitHub "issue").
Website of the course: https://LinuxUpskillChallenge.org
Monthly "Linux Upskill Challenge": https://www.reddit.com/r/linuxupskillchallenge/
Lesson "source": https://github.com/snori74/linuxupskillchallenge
You are free to use this under the terms of the license, but copyright remains with the author.