Book Image

Linux Shell Scripting Cookbook, Second Edition - Second Edition

Book Image

Linux Shell Scripting Cookbook, Second Edition - Second Edition

Overview of this book

The shell remains one of the most powerful tools on a computer system — yet a large number of users are unaware of how much one can accomplish with it. Using a combination of simple commands, we will see how to solve complex problems in day to day computer usage.Linux Shell Scripting Cookbook, Second Edition will take you through useful real-world recipes designed to make your daily life easy when working with the shell. The book shows the reader how to effectively use the shell to accomplish complex tasks with ease.The book discusses basics of using the shell, general commands and proceeds to show the reader how to use them to perform complex tasks with ease.Starting with the basics of the shell, we will learn simple commands with their usages allowing us to perform operations on files of different kind. The book then proceeds to explain text processing, web interaction and concludes with backups, monitoring and other sysadmin tasks.Linux Shell Scripting Cookbook, Second Edition serves as an excellent guide to solving day to day problems using the shell and few powerful commands together to create solutions.
Table of Contents (16 chapters)
Linux Shell Scripting Cookbook
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Using regular expressions


Regular expressions are the heart of text-processing techniques based on pattern matching. For fluency in writing text-processing tools, one must have a basic understanding of regular expressions. Using wild card techniques, the scope of matching text with patterns is very limited. Regular expressions are a form of tiny, highly-specialized programming language used to match text. A typical regular expression for matching an e-mail address might look like [a-z0-9_]+@[a-z0-9]+\.[a-z]+.

If this looks weird, don't worry, it is really simple once you understand the concepts through this recipe.

How to do it...

Regular expressions are composed of text fragments and symbols, which have special meanings. Using these, we can construct any suitable regular expression string to match any text according to the context. As regex is a generic language to match texts, we are not introducing any tools in this recipe. However, it follows in the other recipes in this chapter.

Let's...