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Mastering Linux Shell Scripting

You're reading from   Mastering Linux Shell Scripting Master the complexities of Bash shell scripting and unlock the power of shell for your enterprise

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Product type Paperback
Published in Dec 2015
Publisher
ISBN-13 9781784396978
Length 198 pages
Edition 1st Edition
Tools
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Author (1):
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Andrew Mallett Andrew Mallett
Author Profile Icon Andrew Mallett
Andrew Mallett
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Table of Contents (21) Chapters Close

Mastering Linux Shell Scripting
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
1. 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 sed 9. Automating Apache Virtual Hosts 10. Awk Fundamentals 11. Summarizing Logs with Awk 12. A Better lastlog with Awk 13. Using Perl as a Bash Scripting Alternative 14. Using Python as a Bash Scripting Alternative Index

The history behind awk


The awk command is a mainstay in the command suite in both Unix and Linux. The Unix command awk was first developed by Bell Labs in the 1970's and is named after the surnames of the main authors: Alfred Aho, Peter Weinberger, and Brian Kernighan. The awk command allows access to the awk programming language, which is designed to process data within text streams.

To demonstrate the programming language that is provided with awk, we should create a hello world program. We know this is compulsory for all languages:

$ awk 'BEGIN { print "Hello World!" }'

Not only can we see that this code will print the ubiquitous hello message, we can also generate header information with the BEGIN block. Later, we will see that we can create summary information with an END code block by allowing for a main code block.

We can see the output of this basic command in the following screenshot:

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