Index of Linux Tutorials
Provides technical how-to information, guides, training, links, and other resources for operating Linux.
The Linux Documentation Project
Provides how-to articles, guides, answers to frequently asked questions, announcements, downloads, and other related resources.
Linux Forums
Hosts discussions on topics related to Linux and open source. Also presents downloads, articles, and reviews.
LinuxPlanet
Comprehensive guide to the Linux operating system. Includes discussions, reports, reviews, news, and tutorials.
LinuxQuestions.org
Free online community providing various information and resources for Linux users. With reviews, forums, and tutorials.