What Is Awk Scripting?


Heather Bennett

What Is Awk Scripting?

Awk scripting is a powerful text processing language that allows you to manipulate and analyze data in files or streams. It was developed in the 1970s at Bell Labs and is named after its inventors: Alfred Aho, Peter Weinberger, and Brian Kernighan. Awk combines features of programming languages like C, sed, and grep to provide a concise and expressive way to perform complex tasks on textual data.

The Basics of Awk

If you’re new to awk scripting, let’s start with the basics. Awk works by scanning input files line by line and applying patterns to match specific data.

When a pattern matches, awk performs actions based on predefined rules. These rules are defined using a combination of patterns and actions enclosed in curly braces.

Here’s a simple example:

awk '/pattern/ { action }' file.txt

In the above command, /pattern/ is the pattern to match in each line of the file.txt file. When a match is found, the associated action is executed.

Awk Variables

Awk provides several built-in variables that you can use within your scripts:

  • NF: Represents the number of fields in the current record.
  • NR: Represents the number of records processed so far.
  • $0: Represents the entire current record.
  • $1-$n: Represent individual fields within the current record.

You can also define your own variables within awk using the syntax variable=value. These variables can then be used in your patterns and actions.

Awk Functions

Awk provides a rich set of built-in functions that you can use to manipulate data. Some commonly used functions include:

  • length: Returns the length of a string or the number of elements in an array.
  • split: Splits a string into an array based on a specified delimiter.
  • substr: Extracts a substring from a string.
  • printf: Formats and prints output.

You can also create your own user-defined functions within awk for more complex data manipulation tasks.

Using Awk in Practice

Awk is commonly used for tasks like data extraction, reporting, and text processing. Here are some practical examples:

Extracting Specific Fields

You can use awk to extract specific fields from a file. Let’s say we have a file called employees.txt, where each line represents an employee record with fields separated by commas. To extract the names and ages of all employees, we can use the following awk command:

awk -F ',' '{ print $1, $3 }' employees.txt

In this command, we use the -F ‘,’ option to specify that fields are delimited by commas. The { print $1, $3 } action prints the first and third fields of each line.

Data Summarization

Awk is also useful for summarizing data. Let’s say we have a file called sales.txt, where each line represents a sale with the salesperson’s name, product, and amount. To calculate the total sales amount for each salesperson, we can use the following awk command:

awk '{ sales[$1] += $3 } END { for (person in sales) print person, sales[person] }' sales.txt

This command creates an array called sales to store the total sales amount for each salesperson. The { sales[$1] += $3 } action increments the corresponding element in the array based on the first field (salesperson’s name) and the third field (sale amount). The END pattern is triggered after processing all records and is used to print the final results.


Awk scripting is a versatile tool for manipulating and analyzing text data. With its powerful pattern matching, variables, functions, and array support, awk provides a concise and expressive way to perform complex tasks. By mastering awk scripting, you can save time and effort when working with textual data.

So go ahead and explore awk further to unlock its full potential!

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