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Learning AWK Programming

You're reading from   Learning AWK Programming A fast, and simple cutting-edge utility for text-processing on the Unix-like environment

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Product type Paperback
Published in Mar 2018
Publisher Packt
ISBN-13 9781788391030
Length 416 pages
Edition 1st Edition
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Author (1):
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Shiwang Kalkhanda Shiwang Kalkhanda
Author Profile Icon Shiwang Kalkhanda
Shiwang Kalkhanda
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Table of Contents (11) Chapters Close

Preface 1. Getting Started with AWK Programming FREE CHAPTER 2. Working with Regular Expressions 3. AWK Variables and Constants 4. Working with Arrays in AWK 5. Printing Output in AWK 6. AWK Expressions 7. AWK Control Flow Statements 8. AWK Functions 9. GNU's Implementation of AWK – GAWK (GNU AWK) 10. Practical Implementation of AWK

Regular expression operators

When we use the == condition, AWK looks for an exact match. However, when we use the match operator (~), AWK looks for a partial match. Here, ~ means contains. To match a specific pattern using regular expression, ~ and !~ are used. Regular expression comparisons are performed using a matching expression built with either of these two operators. The right-hand side of the ~ or !~ operator could be a regular expression or string enclosed between forward slashes (/…/).

Match operator (~):

It is represented as a tilde (~) symbol. It matches a pattern in a specific field. Its syntax is as follows:

expression ~ /regexpr/

It matches if the string value of the expression contains a sub-string matched by regular expression regexpr.

For example, if you want to print the records containing Singh or Kapur in last name field from the employees database...

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