The Advanced Bash Scripting Guide is both a reference and a tutorial on shell scripting. This comprehensive book, the equivalent of 1,032 print pages, covers almost every aspect of shell scripting. It contains 382 profusely commented illustrative examples, a number of tables, and a cross-linked index/glossary. Not just a shell scripting tutorial, this book also provides an introduction to basic programming techniques, such as sorting and recursion. Included scripts are the Game of Life, a Perquackey variant, a Morse code trainer, and an implementation of the Gronsfeld Cipher. This book is suited for both individual study and classroom use. It covers Bash, up to and including version 4.2. Note that users of miniaturized single-board computers running Linux, such as the Raspberry Pi and the Beagle Bone, would find this Guide useful for learning and running Bash scripts to explore and expand the capabilities of these small, but powerful machines.
The Header and Envelope rewrite mini-HOWTO explains how to rewrite your from address differently in the mail header and the mail envelope. This may be necessary, for example, if your ISP requires you to send mail with one address, but you are subscribed to mailing lists with a different address, or want others to see a forwarding address instead of your ISP's address.
swpartc is a simple but reliable utility for copying the data contents of one file or partition into another one and vice versa without losing a bit. The partitions must have the same size. It uses a crash recovery technique (a small back-up file), which means that even if the process is killed or the computer crashes, the user can safely resume the swapping operation later.