Linux Command Line
This site has a pretty lots of most used command line in linux. Easy to read especially for semi-beginner.
Vi Cheatsheet
2 pages document with lots of command to go through vi editor. One of my favorite command in vi is :set number.
Bash Scripting Cheatsheet
A nearly complete cheatsheet of all command to do bash scripting. Good designed page and easy to navigate.
Markdown Cheatsheet
Another beautiful designed cheatsheet that contains markdown syntax.
AWK Tutorial
An official and complete tutorial of AWK. It’s basically web-based book, so no need to wonder why the page is so long hehe.
Regex Tutorial
Well explained tutorial with example and summary about regex.
SED Tutorial
Another well explained tutorial with example about SED Command in Linux/Unix.
Markdown Web Editor
Online markdown editor where you can edit your text and transformed it into markdown format side by side.
Interactive Vim Tutorial
Good web to learn vim. Complete with tutorial, practice, and development.
Virtualization A Complete Guide
This page encover virtualization and its other aspects. Well explained and easy to understand.