Reference Blog Open Source

Basic MySQL

http://www.pantz.org/software/mysql/mysqlcommands.html

Mysql Cheat Sheet

http://cse.unl.edu/~sscott/ShowFiles/SQL/CheatSheet/SQLCheatSheet.html

Ubuntu Pocket Guide

http://ubuntupocketguide.com/index_main.html

Ubuntu Cheat Sheet

http://fosswire.com/post/2008/04/ubuntu-cheat-sheet/

John Blog

http://techovdoom.blogspot.com/

Izhar Blog

http://shab4b.blogspot.com/

"Shell" is the most important thing when you work with open source environment, below you can learn  a lot of command inside Linux / Unix

 Tips

http://linuxcommand.org/learning_the_shell.php

http://www.pixelbeat.org/cmdline.html