$ UNIX History
$ Getting started with a FREE OS
$ My Ubuntu post-install TODO list
$ UBUNTU - GNU/Linux at its best
$ The Grymoire - home for UNIX wizards
$ Unix/Linux Shell Scripting Tutorial
$ Advanced Bash-Scripting Guide
$ The Linux Documentation Project
$ 50 handy Ubuntu time-saving tips
$
$
$
$ SDF Public Access UNIX System
$
linux.org
gnu.org