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

Chapter 7. Creating Building Blocks with Functions

In this chapter, we will dive into the wonderful world of functions. We can look at these as modular building blocks creating powerful and adaptive scripts. By creating functions, we add the code in a single building block isolated from the rest of the script. Focusing on improvements of a single function is a lot easier than trying to improve the script as a single object. Without functions, it is difficult to hone in on problem areas and the code is often repeated, it means that updates need to happen in many locations. Functions are named as blocks of code or scripts within scripts and they can overcome many problems associated with a more complex code.

As we make our way through the chapter, we will cover the following topics:

  • Functions

  • Passing parameters to functions

  • Returning values

  • Menu using functions