I have rebuilt my “Effective Shell” series as an online book - it's available now on:
The whole site is built from a GitHub repo at github.com/dwmkerr/effective-shell. It is open for contributions, changes, issues and suggestions. I've also added a comment section to each page to get input.
To keep the material as accessible as possible, I have added a new section for beginners, to help anyone who has not used a shell before. It goes over who the book is useful for, what the shell is, and how to set up your computer to work through the material:
All comments and suggestions are welcome!