UNIX has hundreds if not thousands of commands, and it's impossible to remember every option and nuance. But, happily, you don't have to: man, UNIX's built-in, online reference system, is man's best friend. Take a look at this shortcut guide to the UNIX man pages system.

Linux administrators cannot live by the GUI alone. That's why we've compiled the most essential Linux commands into this convenient guide. We designed this guide specifically for Linux managers and system administrators as a reference library of only the most useful utilities. By learning a few simple tools, command-line cowards can turn into scripting commandos, getting the most out of Linux by executing kernel and shell commands.

"My previous reference for practical linux commands was surprisingly popular
with over 3.5 million hits in nearly 5 years. So I've decided to start compiling
another list of somewhat more involved/esoteric commands."

If you just want enough information to fix your problem quickly, you can read the How-To section of this post and skip the rest. I would highly recommend reading everything though, as a good understanding of the concepts and commands outlined here will serve you well in the future. We also have Video and Audio included with this post that may be a good quick reference for you.

UNIX has hundreds if not thousands of commands, and it's impossible to remember every option and nuance. But, happily, you don't have to: man, UNIX's built-in, online reference system, is man's best friend.

Cheat sheet act as a reference tool which provides cut and paste kind of commands to complete a specific task.

Ubuntu Pocket Guide and Reference has been released and available for download from the official (authors') website. This guide is written by Keir Thomas and he claims that it is a totally unique and concise guide for everyday Ubuntu user.

Ubuntu Pocket Guide and Reference is a free book written by Keir Thomas, the well-known author of Beginning Ubuntu Linux and co-author of Ubuntu Kung Fu, two popular books about Ubuntu Linux. His latest book is called Ubuntu Pocket Guide and Reference and it is available as a free PDF download from the official website, or as print edition from Amazon.com for USD 11,99.

A very quick command line tip today, for users of pretty much any Unix-based operating system, including Linux distributions. When you're looking up information on a certain web site or domain name, you might be used to using whois functions on websites such as to see who owns a domain.