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

We are still making progress in leaps and bounds in script writing. I hope these ideas stay with you and you find the code examples useful. Functions are very important for the ease of maintenance of your scripts and their ultimate functionality. The easier the scripts are to maintain, the more likely you are to add improvements over time. We can define functions at the command line or within scripts but they need to be included in the script before they are used.

The functions themselves are loaded into memory while the script is running, but as long as the script is forked and not sourced, they will be released from memory once the script is finished. We have touched a little upon sed in this chapter and we will look more at using the stream editor (sed) in the next chapter. The sed command is very powerful and we can make good use of it within scripts.

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