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Mastering Linux Shell Scripting

You're reading from   Mastering Linux Shell Scripting A practical guide to Linux command-line, Bash scripting, and Shell programming

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Product type Paperback
Published in Apr 2018
Publisher
ISBN-13 9781788990554
Length 284 pages
Edition 2nd Edition
Languages
Tools
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Authors (2):
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Mokhtar Ebrahim Mokhtar Ebrahim
Author Profile Icon Mokhtar Ebrahim
Mokhtar Ebrahim
Andrew Mallett Andrew Mallett
Author Profile Icon Andrew Mallett
Andrew Mallett
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Table of Contents (17) Chapters Close

Preface 1. The What and Why of Scripting with Bash FREE CHAPTER 2. Creating Interactive Scripts 3. Conditions Attached 4. Creating Code Snippets 5. Alternative Syntax 6. Iterating with Loops 7. Creating Building Blocks with Functions 8. Introducing the Stream Editor 9. Automating Apache Virtual Hosts 10. AWK Fundamentals 11. Regular Expressions 12. Summarizing Logs with AWK 13. A Better lastlog with AWK 14. Using Python as a Bash Scripting Alternative 15. Assessments 16. Other Books You May Enjoy

Summary

We are still making progress in leaps and bounds in script writing. I hope these ideas stay with you and you find the code examples useful. Functions are very important for the ease of maintenance of your scripts and their ultimate functionality. The easier the scripts are to maintain, the more likely you are to add improvements over time. We can define functions at the command line or within scripts but they need to be included in the script before they are used.

The functions themselves are loaded into memory while the script is running, but as long as the script is forked and not sourced, they will be released from memory once the script is finished. We have touched a little upon sed in this chapter and we will look more at using the stream editor (sed) in the next chapter. The sed command is very powerful and we can make good use of it within scripts.

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