Unix Shells By Example, by Ellie Quigley

If want to learn about shells and you learn by example, like I do, this book is essential.

The first 6 chapters (nearly 200 pages) goes over the basics of all shells; what they are, what they do, what programs are most used to manipulate data in them. There are whole chapters devoted to grep, sed and awk, and the author doesn't skimp on details. You will be a virtual grep/sed/awk guru by the time you learn everything in these chapters.

Chapters 7-15 introduce and get you into scripting of each major shell: Bourne shell, C and TC Shells, Korn shell, and Bash (bash is the standard shell in most linux distributions). It then spends a chapter on general debugging shell scripting problems.

The last chapters touch upon system administrating via the shell (rather than using gui tools). Again taught by example so it's very clear to the reader.

I learned more about bash (my shell of choice) from this guide than any other that I've read, and not for lack of trying, I've read several bash guides. I was happy to see that examples given were explained line-by-line so you don't lose track of what is happening in each example. I was delighted by the useful appendices covering useful commands and giving side by side shell comparisons.

This is my favorite shell book to date.