Carl Albing - Bash Cookbook

Copyright 2008 O'Reilly Media, Inc.

This book is for anyone who uses a Unix or Linux system, as well as system administrators who may use several systems on any given day. With it, you will be able to create scripts that allow you to accomplish more, in less time, more easily, consistently, and repeatably than ever before.

Anyone? Yes. New users will appreciate the sections on automating repetitive tasks, making simple substitutions, and customizing their environment to be more friendly and perhaps behave in more familiar ways. Power users and administrators will find new and different solutions to common tasks and challenges. Advanced users will have a collection of techniques they can use at a moment's notice to put out the latest fire, without having to remember every little detail of syntax.

Ideal readers include:

This book will only briefly cover basic and intermediate shell scriptingsee Learning the bash Shell by Cameron Newham (O'Reilly) and Classic Shell Scripting by Nelson H.F. Beebe and Arnold Robbins (O'Reilly) for more in-depth coverage. Instead, our goal is to provide solutions to common problems, with a strong focus on the "how to" rather than the theory. We hope this book will save you time when figuring out solutions or trying to remember syntax. In fact, that's why we wrote this book. It's one we wanted to read through to get ideas, then refer to practical working examples when needed. That way we don't have to remember the subtle differences between the shell, Perl, C, and so forth.

This book assumes you have access to a Unix or Linux system (or see , "Testing Scripts in VM ware") and are familiar with logging in, typing basic commands, and using a text editor. You do not have to be root to use the vast majority of the recipes, though there are a few, particularly dealing with installing bash, where root access will be needed.

This book covers bash , the GNU Bourne Again Shell, which is a member of the Bourne family of shells that includes the original Bourne shell sh , the Korn shell ksh , and the Public Domain Korn Shell pdksh . While these and other shells such as dash , and zsh are not specifically covered, odds are that most of the scripts will work pretty well with them.

You should be able to read this book cover to cover, and also just pick it up and read anything that catches your eye. But perhaps most importantly, we hope that when you have a question about how to do something or you need a hint, you will be able to easily find the right answeror something close enoughand save time and effort.

A great part of the Unix philosophy is to build simple tools that do one thing well, then combine them as needed. This combination of tools is often accomplished via a shell script because these commands, called pipelines, can be long or difficult to remember and type. Where appropriate, we'll cover the use of many of these tools in the context of the shell script as the glue that holds the pieces together to achieve the goal.

This book was written using OpenOffice.org Writer running on whatever Linux or Windows machine happened to be handy, and kept in Subversion (see , "Processing Files with No Line Breaks."