Book Image

Learning AWK Programming

By : Shiwang Kalkhanda
5 (1)
Book Image

Learning AWK Programming

5 (1)
By: Shiwang Kalkhanda

Overview of this book

AWK is one of the most primitive and powerful utilities which exists in all Unix and Unix-like distributions. It is used as a command-line utility when performing a basic text-processing operation, and as programming language when dealing with complex text-processing and mining tasks. With this book, you will have the required expertise to practice advanced AWK programming in real-life examples. The book starts off with an introduction to AWK essentials. You will then be introduced to regular expressions, AWK variables and constants, arrays and AWK functions and more. The book then delves deeper into more complex tasks, such as printing formatted output in AWK, control flow statements, GNU's implementation of AWK covering the advanced features of GNU AWK, such as network communication, debugging, and inter-process communication in the GAWK programming language which is not easily possible with AWK. By the end of this book, the reader will have worked on the practical implementation of text processing and pattern matching using AWK to perform routine tasks.
Table of Contents (11 chapters)

Conditional statements

Conditional statements such as if and switch are used to test expressions and control the flow of execution in AWK programs. All control statements start with special keywords such as if and switch to differentiate them from simple expressions. Within one conditional statement block, we can have other multiple statements separated by braces, newlines, or semicolons. Such conditional statements are known as compound statements.

The if statement

if is a conditional statement used to control the flow of a program. AWK supports three types of if statements:

  • if
  • if...else
  • if...elseif...elseif...