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Learn Linux Shell Scripting – Fundamentals of Bash 4.4

You're reading from   Learn Linux Shell Scripting ‚àö¬¢‚Äö√ᬮ‚Äö√Ñ√∫ Fundamentals of Bash 4.4 A comprehensive guide to automating administrative tasks with the Bash shell

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Product type Paperback
Published in Dec 2018
Publisher Packt
ISBN-13 9781788995597
Length 452 pages
Edition 1st Edition
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Author (1):
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Sebastiaan Tammer Sebastiaan Tammer
Author Profile Icon Sebastiaan Tammer
Sebastiaan Tammer
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Table of Contents (20) Chapters Close

Preface 1. Introduction 2. Setting Up Your Local Environment FREE CHAPTER 3. Choosing the Right Tools 4. The Linux Filesystem 5. Understanding the Linux Permissions Scheme 6. File Manipulation 7. Hello World! 8. Variables and User Input 9. Error Checking and Handling 10. Regular Expressions 11. Conditional Testing and Scripting Loops 12. Using Pipes and Redirection in Scripts 13. Functions 14. Scheduling and Logging 15. Parsing Bash Script Arguments with getopts 16. Bash Parameter Substitution and Expansion 17. Tips and Tricks with Cheat Sheet 18. Assessments 19. Other Books You May Enjoy

Summary

In this chapter, we have presented Bash functions. Functions are generic chains of commands that can be defined once, before being called multiple times. Functions are reusable and can be shared between multiple scripts.

Variable scopes were introduced. The variables we've seen thus far were always globally scoped: they were available to the entire script. However, with the introduction of functions, we encounter locally scoped variables. These are only accessible within a function and marked with the local keyword.

We learned that functions can have their own independent set of parameters, which can be passed as arguments when the function is called. We proved that these are in fact different from the global arguments passed to the script (unless all arguments are passed through to the function, of course). We gave an example about returning output from...

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