The quickest way to learn LINUX

What is the quickest way to learn LINUX?

with regards to LINUX thing, I always refer on this site... http://www.linux.ie/newusers/beginners-linux-guide/
this site contains the following stuff:

Installing the Operating System
* General Information on Installing the OS
* Partitioning your Hard Drive for the Linux Installation
* Booting Up
* The install process

Using the Command Shell
* About shells
* Basic Shell Commands, move, copy, etc.
* Using the emacs text editor
* Using the vi text editor
* Setting up the executable path
* Jumping to the last directory you were in
* Finding out how much space a dir takes up
* Giving an app more processing time
* Uncompressing tgz files
* Using the ftp client
* Using the ps command to view processes
* Using the find command
General Information
* What the root directories hold

Configuring Hardware
* Setting up Plug and Play Devices
* Setting up the Awe 16/32/64 PnP Card in Linux
* Setting up a Modem in Linux
* Setting up a wheelmouse

Becoming a Super User
* Introduction for SU candidates
* Setting up an Internet Connection