The official "Ubuntu 10.04 LTS Packaging Guide" is primarily addressed to those who would like to make and maintain Ubuntu packages. Although many of the concepts in this guide could be used to make binary packages for personal use, it is designed for those people wanting to distribute their packages to and for others.
The official "Ubuntu 10.04 LTS Server Guide" contains information on how to install and configure various server applications on your Ubuntu system to fit your needs.
The official "Ubuntu 11.04 Server Guide" contains information on how to install and configure various server applications on your Ubuntu system to fit your needs.
The Bash Guide for Beginners (Second Edition) discusses concepts useful in the daily life of the serious Bash user. While a basic knowledge of shell usage is required, it starts with a discussion of shell building blocks and common practices. Then it presents the grep, awk and sed tools that will later be used to create more interesting examples. The second half of the course is about shell constructs such as loops, conditional tests, functions and traps, and a number of ways to make interactive scripts. All chapters come with examples and exercises that will help you become familiar with the theory.