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Linux Shell Scripting Essentials

Linux Shell Scripting Essentials

By : Sinny Kumari
4.5 (2)
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Linux Shell Scripting Essentials

Linux Shell Scripting Essentials

4.5 (2)
By: Sinny Kumari

Overview of this book

Shell scripting is a quick method to prototype complex applications or problems. Shell scripts are a collection of commands to automate tasks, usually those for which the user has a repeated need, when working on Linux-based systems. Using simple commands or a combination of them in a shell can solve complex problems easily. This book starts with the basics, including essential commands that can be executed on Linux systems to perform tasks within a few nanoseconds. You’ll learn to use outputs from commands and transform them to show the data you require. Discover how to write shell scripts easily, execute script files, debug, and handle errors. Next, you’ll explore environment variables in shell programming and learn how to customize them and add a new environment. Finally, the book walks you through processes and how these interact with your shell scripts, along with how to use scripts to automate tasks and how to embed other languages and execute them.
Table of Contents (10 chapters)
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9
Index

Chapter 3. Effective Script Writing

To write an effective script in shell, it is very important to know about the different utilities that shell provides. Similar to other programming languages, shell programming also requires a way to specify skipping or running certain commands under certain conditions. To perform a certain task on the list of elements, looping constructs are needed in shell as well.

In this chapter, we will cover topics such as if, else, case, and select that can be used to run a certain block of commands according to the condition. We will see the for, while, and until constructs, which are used to loop over a certain block of commands in a script. We will see how the exit code, after the execution of a command or script, plays an important role in knowing whether a command was executed successfully or not. We will also see how a function can be defined in shell, which will allow us to write modular and reusable code from now on.

This chapter will cover the...

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