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Linux Command Line and Shell Scripting Techniques

You're reading from   Linux Command Line and Shell Scripting Techniques Master practical aspects of the Linux command line and then use it as a part of the shell scripting process

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Product type Paperback
Published in Mar 2022
Publisher Packt
ISBN-13 9781800205192
Length 552 pages
Edition 1st Edition
Tools
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Authors (2):
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Jasmin Redzepagic Jasmin Redzepagic
Author Profile Icon Jasmin Redzepagic
Jasmin Redzepagic
Vedran Dakic Vedran Dakic
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Vedran Dakic
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Table of Contents (19) Chapters Close

Preface 1. Chapter 1: Basics of Shell and Text Terminal 2. Chapter 2: Using Text Editors FREE CHAPTER 3. Chapter 3: Using Commands and Services for Process Management 4. Chapter 4: Using Shell to Configure and Troubleshoot a Network 5. Chapter 5: Using Commands for File, Directory, and Service Management 6. Chapter 6: Shell-Based Software Management 7. Chapter 7: Network-Based File Synchronization 8. Chapter 8: Using the Command Line to Find, Extract, and Manipulate Text Content 9. Chapter 9: An Introduction to Shell Scripting 10. Chapter 10: Using Loops 11. Chapter 11: Working with Variables 12. Chapter 12: Using Arguments and Functions 13. Chapter 13: Using Arrays 14. Chapter 14: Interacting with Shell Scripts 15. Chapter 15: Troubleshooting Shell Scripts 16. Chapter 16: Shell Script Examples for Server Management, Network Configuration, and Backups 17. Chapter 17: Advanced Shell Script Examples 18. Other Books You May Enjoy

Checking if you're running as root

There are different ways of checking if we're running a script as root. We can use environment variables, just as we can use the whoami or id commands to check if it equals root/number 0 or not.

Getting ready

We'll continue using the cli1 machine for this recipe, so make sure that it's powered on.

How to do it…

Let's create a short snippet of Bash shell script code that's going to help us find out whether we're running a script as root or not. It's a rather simple thing to do in Linux, considering that we have easy access to an environment variable called EUID, and reading its value is enough to determine whether we're running as root (EUID=0) or not (EUID value > 1):

#!/bin/bash
# V1.0 / Jasmin Redzepagic / 01/11/2021 Initial script version 
# Distribution allowed under GNU Licence V2.0 
# First, we need to check if our environment variable UID is set to
# 0 or not and branch...
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