Book Image

Mastering Linux Shell Scripting - Second Edition

By : Mokhtar Ebrahim, Andrew Mallett
5 (1)
Book Image

Mastering Linux Shell Scripting - Second Edition

5 (1)
By: Mokhtar Ebrahim, Andrew Mallett

Overview of this book

In this book, you’ll discover everything you need to know to master shell scripting and make informed choices about the elements you employ. Grab your favorite editor and start writing your best Bash scripts step by step. Get to grips with the fundamentals of creating and running a script in normal mode, and in debug mode. Learn about various conditional statements' code snippets, and realize the power of repetition and loops in your shell script. You will also learn to write complex shell scripts. This book will also deep dive into file system administration, directories, and system administration like networking, process management, user authentications, and package installation and regular expressions. Towards the end of the book, you will learn how to use Python as a BASH Scripting alternative. By the end of this book, you will know shell scripts at the snap of your fingers and will be able to automate and communicate with your system with keyboard expressions.
Table of Contents (17 chapters)

Summary

One of the most important and time-consuming tasks in scripting is building all of the conditional statements that we need to make the script usable and robust. There is an 80/20 rule that is often spoken of. This is where 20 percent of your time is spent in writing the main script and 80 percent of the time is spent in ensuring that all of the possible eventualities are correctly handled in the script. This is what we refer to as the procedural integrity of the script, where we try to cover each scenario carefully and accurately.

We started by looking at a simple test with command-line lists. If the actions needed are simple, then these provide great functionality and are easily added. Where more complexity is required, we add if statements.

Using the if statements, we can extend them as required using the else and elif keywords. Don't forget that elif keywords need...