Book Image

Mastering Linux Shell Scripting

By : Andrew Mallett
Book Image

Mastering Linux Shell Scripting

By: Andrew Mallett

Overview of this book

Shell scripting is a quick method to prototype a complex application or a problem by automating tasks when working on Linux-based systems. Using both simple one-line commands and command sequences complex problems can be solved with ease, from text processing to backing up sysadmin tools. In this book, you’ll discover everything you need to know to master shell scripting and make informed choices about the elements you employ. 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. Implement functions and edit files using the Stream Editor, script in Perl, program in Python – as well as complete coverage of other scripting languages to ensure you can choose the best tool for your project.
Table of Contents (21 chapters)
Mastering Linux Shell Scripting
About the Author
About the Reviewer

More conditions with elif

Moving onto 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 a pseudo-code:

if condition; then
elif condition; then
exit 0

A script may make life easier for the operator by providing a simplified selection for a more complex 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 rewarded with the reliability of the scripted application.

Creating the using elif

We can revisit the script that we created...