Linux

• sysadmin tutorials-- https://www.digitalocean.com/community/tutorials

• sysadmin cheatsheet http://cheatsheetworld.com/programming/unix-linux-cheat-sheet/

• tmux cheatsheet https://gist.github.com/MohamedAlaa/2961058

• git cheatsheet https://github.github.com/training-kit/downloads/github-git-cheat-sheet/