Unix, bash shell, git and GitHub references

A list of resources for Unix and bash shell scripting:

The Wikibooks page of bash shell scripting:
https://en.wikibooks.org/wiki/Bash_Shell_Scripting

The Unix workbench, the book of Sean Kross:
https://github.com/seankross/the-unix-workbench

The introductory page to GitHub:
https://guides.github.com/activities/hello-world/

A formal introduction to git:
https://git-scm.com/book/en/v2/Getting-Started-Git-Basics

A more straitghtforward introduction to git:
http://rogerdudler.github.io/git-guide/ 

A tutorial to use GNU screen to manage persistent terminal sessions:
https://www.linode.com/docs/networking/ssh/using-gnu-screen-to-manage-persistent-terminal-sessions

The GNU screen manual
https://www.gnu.org/software/screen/manual/screen.html

Feel free to report additional resources!