The following guides all come from the The Linux Document Project. The latest version of these guides plus many more guides, HOWTOS, and FAQs are available at the The Linux Document Project.
Introduction to Linux (HTML or PDF)
This guide was created as an overview of the Linux Operating System, geared toward new users as an exploration tour and getting started guide, with exercises at the end of each chapter. For more advanced trainees it can be a desktop reference, and a collection of the base knowledge needed to proceed with system and network administration. This book contains many real life examples derived from the author's experience as a Linux system and network administrator, trainer and consultant. We hope these examples will help you to get a better understanding of the Linux system and that you feel encouraged to try out things on your own.
GNU/Linux Command-Line Tools Summary (HTML or PDF)
This document is an attempt to provide a summary of useful command-line tools available to a GNU/Linux based operating system, the tools listed are designed to benefit the majority of users and have being chosen at the authors discretion. This document is not a comprehensive list of every existent tool available to a GNU/Linux based system, nor does it have in-depth explanations of how things work. It is a summary which can be used to learn about and how to use many of the tools available to a GNU/Linux-based operating system.
The Linux Dictionary (HTML or PDF)
This document is designed to be a resource for those Linux users wishing to seek clarification on Linux/UNIX/POSIX related terms and jargon. At approximately 9000 definitions and one thousand pages it is one of the largest Linux related dictionaries currently available.
BASH Programming - Introduction (HTML or PDF)
This article intends to help you to start programming basic to intermediate shell scripts. It does not intend to be an advanced document (see the title).
Bash Beginners Guide (HTML or PDF)
The Bash Guide for Beginners gets you started with Bash scripting and bridges the gap between the Bash HOWTO and the Advanced Bash Scripting Guide. Everybody who wants to make life easier on themselves, power users and sysadmins alike, can benefit from reading this practical course. The guide contains lots of examples and exercises at the end of each chapter, demonstrating the theory and helping you practice. Bash is available on a wide variety of UNIX, Linux, MS Windows and other systems.
Advanced Bash-Scripting Guide (HTML or PDF)
This document is both a tutorial and a reference on shell scripting with Bash. It assumes no previous knowledge of scripting or programming, but progresses rapidly toward an intermediate/advanced level of instruction. The exercises and heavily-commented examples invite active reader participation. Still, it is a work in progress. The intention is to add much supplementary material in future updates to this document, as it evolves into a comprehensive book that matches or surpasses any of the shell scripting manuals in print.
Bash Doc Directory
Under Debian you should be able to access the Bash documentation in the directory /usr/share/doc/bash
The Linux Document Project's HOWTOs (HTML)
The Linux HOWTOs are detailed "how to" documents on specific subjects.

The entire HOWTO can be installed on your Debian system into the directory /usr/share/doc/Debian/ via the Debian packages "doc-linux-html" and "doc-linux-nonfree-html".