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Learn Linux Quickly

You're reading from   Learn Linux Quickly A beginner-friendly guide to getting up and running with the world's most powerful operating system

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Product type Paperback
Published in Aug 2020
Publisher Packt
ISBN-13 9781800566002
Length 338 pages
Edition 1st Edition
Tools
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Author (1):
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Ahmed AlKabary Ahmed AlKabary
Author Profile Icon Ahmed AlKabary
Ahmed AlKabary
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Toc

Table of Contents (24) Chapters Close

Preface 1. Your First Keystrokes 2. Climbing the Tree FREE CHAPTER 3. Meet the Editors 4. Copying, Moving, and Deleting Files 5. Read Your Manuals! 6. Hard versus Soft Links 7. Who Is Root? 8. Controlling the Population 9. Piping and I/O Redirection 10. Analyzing and Manipulating Files 11. Let's Play Find and Seek 12. You Got a Package 13. Kill the Process 14. The Power of Sudo 15. What's Wrong with the Network? 16. Bash Scripting Is Fun 17. You Need a Cron Job 18. Archiving and Compressing Files 19. Create Your Own Commands 20. Everyone Needs Disk Space 21. echo "Goodbye My Friend" 22. Assessments 23. Other Books You May Enjoy

visudo versus /etc/sudoers

You may have noticed that I used the command visudo to edit the file /etc/sudoers, and you might ask yourself a very valid question: why not just edit the file /etc/sudoers directly without using visudo? Well, I will answer your question in a practical way.

First, run the visudo command and add the following line:

THISLINE=WRONG

Now try to save and exit:

root@ubuntu-linux:~# visudo
>>> /etc/sudoers: syntax error near line 14 <<<
What now?
Options are:
(e)dit sudoers file again
e(x)it without saving changes to sudoers file
(Q)uit and save changes to sudoers file (DANGER!)
What now?

As you can see, the visudo command detects an error, and it specifies the line number where the error has occurred.

Why is this important? Well, if you saved the file with an error in it, all the sudo rules in /etc/sudoers will not work! Let’s hit Q to save the changes and then try to list the sudo commands that can be run by user smurf:

What now? Q
root@ubuntu...
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