The shell is something of a hot topic at the moment, which is as it should be given that it presents a primary and incredibly versatile interface to the OS. Indeed, such an interface can readily be regarded as an essential part of any operating system, mediating as it does between user and hardware abstractions. However, many publishers on witnessing this surge of interest have chosen to respond poorly, either producing incorrectly pitched material which rarely rises to the true flexibility of the shell, or with an exercise-ridden schoolroom approach, often recycling material from the early days of Unix-like OSes.

Thankfully Apress, renowned for publishing niche works which address the needs of professionals, have released this quality work, which rises to the practical shell challenge and perhaps provides the most comprehensive coverage of the highly usable but often overlooked Z shell, zsh. Indeed, though the work is titled From Bash to Z Shell, it should really be refered somewhat less elegantly as The Bash and Z Shells, given that only a brief comparison is made to other shells in the earlier, more generic chapters of this work. That said, enough ground is covered here, to allow for efficient work on any system, and as Bash is the default GNU/Linux shell, and zsh is so powerful and does incorporate the best features from other C-type shells, the choice here is a good one which allows for digging deep into the practical subject at hand.

From Bash to Z Shell is well written, beautifully presented and material is intelligently divided into three manageable chunks. It takes itself seriously as resource and technical work of merit, and thus even includes valuable advice for those not used to such an information-rich environment. The first part, which covers basic shell use for the absolute beginner, explains core concepts such as processes and inheritance in meticulous detail, and more practical aspects of shell use are demonstrated with clearly formatted example material.

Whilst advanced topics such as globbing, or pattern matching, and shell history manipulation, which are covered in the second part, are barely touched upon here, the first generic portion does manage to push beyond more experienced users levels of knowledge, helpfully providing background which the self-taught may have overlooked. The second segment of this generous work really does constitute the meat of this volume, and readily lives up to the promise of conquering the command line. The zsh shell's hugely comprehensive and eminently usable completion functions are well documented with extensive examples, and jobs and processes receive a complete rundown. The Z shell really does come across in a good light in comparison with the more familiar bash, but both shells are well represented as to solidly backed up tircks and tips.

It's also good to see that From Bash to Z Shell doesn't try to spread itself too thin, in contrast to other siuch works which provide often unnecessary guides to shell scripting padded out with generic programming material. Scripting is covered both in the introduction and in the final part, which is concerned with extending the shell, but the material here does not dominate and is of good quality. Advanced topics such as writing editor commands or completion functions are thus able to receive good attention. Further appendices detailing common Unix programs and offering a glossary of terms round out a proud, rich work which should enable any level of user to share deeply in the riches of the command line.

Authors: Oliver Kiddle al.
Publisher: Apress
ISBN: 1590593766

Review by Martin House