Book Review: Classic Shell Scripting

Reviewed by Peter H. Salus

Classic Shell Scripting
Arnold Robbins & Nelson H.F. Beebe
O'Reilly & Associates, 2005
ISBN 0596005954
534 pages

If you program on a Unix box or a Linux box, you use the shell. It doesn't matter whether it's sh, csh, ksh, bash, or... You use the shell. And, in all likelihood, if you use the shell, you use scripts.

Robbins and Beebe have produced a book that is really good in a variety of ways: it is well-written; it is well-organized; it is full of worthwhile examples and instances; and the code is lucid and clear.

For those of you puzzled about all this, let me point out that languages like C, C++ and Java are compiled — the source code is translated into object code and then executed. Scripting languages (like awk, Perl, Python, and Ruby) are interpreted. Compiled languages are convenient; scripting languages work at a higher level.

And, because every type of Unix and Linux has a shell, shell scripts are portable to a very, very large extent. Moreover, scripts save time and effort; and shell scripts save work across platforms.

Robbins and Beebe have organized Classic Shell Scripting into 15 chapters:

Background
Getting Started
Searching and Substitutions
Text Processing Tools
Pipelines Can Do Amazing things
Variables, Making Decisions, and Repeating Actions
Input and Output...
Production Scripts
Enough awk to be Dangerous
Working with Files
Extended Example: Merging User Databases
Spellchecking
Processes
Shell Portability Issues ...
Secure Shell Scripts ...

There are also three Appendices; a Bibliography; a Glossary; and an elaborate Index.

I've been using a number of flavors of Unix and Linux for more than 25 years. I learned a lot from this book. I enjoyed the chapter on Text Processing Tools a great deal, and I worked my way through the Spellchecking chapter. (As Robbins and Beebe state, every OS has a spellchecker built in, but you can learn a lot by constructing one. I did.)

This is an excellent book. Buy it now!

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