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)

More conditions with elif

Moving on to where we require a greater degree of control, we can use the elif keyword. Unlike else, elif requires an additional condition to be tested for each elif. In this way, we can provide for different circumstances. We can add in as many elif conditions as required. The following shows some pseudocode:

if condition; then 
statement 
elif condition; then 
statement 
else 
statement 
fi 
exit 0 

A script may make life easier for the operator by providing a simplified selection for a more complex piece of code. Even though the script becomes gradually more complex to meet the requirements, to the operator the execution is greatly simplified. It is our job to enable users to run more complex operations easily from the command line when creating scripts. Often, this will necessitate the addition of more complexity to our scripts; however, we will be...