Learn The Command Line

• Learn Enough Command Line to Be Dangerous by Michael Hartl - a tutorial introduction to the Unix command line.

• Codecademy's Learn the Command Line - interactive course.

• LinuxCommand and The Linux Command Line book by William Shotts

• The Art of Command Line - master the command line, in one page.

• Bash Guide - a guide to learn bash.

• Shell Style Guide by Paul Armstrong

• The Bash Hackers Wiki - human-readable documentation.