computing

An Introduction to the Command-Line (on Unix-like systems)   Everybody Knows How to Use a Computer, but Not Everyone Knows How to Use the Command Line. Yet This is the Gateway to Doing Anything and Everything Sophisticated with a Computer and the Most Natural Starting Place to Learn Programming
100 Useful Command-Line Utilities   A Guide to 100 (ish) Useful Commands on Unix-like systems
A Brief Introduction to Git   An Introduction to Git for Beginners as well as a Reference to Basic Git Commands