Vim

How To Learn Vim: A Four Week Plan Learn Vim the Simple Way iggredible/Learn-Vim: Learning Vim and Vimscript doesn’t have to be hard. This is the guide that you’re looking for 📖 Interactive Vim tutorial Learn Vim For the Last Time: A Tutorial and Primer - Daniel Miessler

Shell

The Bash Guide Learn Shell - Free Interactive Shell Tutorial

Regex

RegexOne - Learn Regular Expressions - Lesson 1: An Introduction, and the ABCs Regular Expressions (Regex) Tutorial: How to Match Any Pattern of Text - YouTube learn-regex/README.md at master · ziishaned/learn-regex

Git

Git - Book