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)

Summary

In this chapter, we learned about different types of built-in and user-defined functions that accept zero or more arguments and return a value. Function arguments can be made up of expressions that are evaluated before calling a function. We began by looking at built-in functions such as arithmetic functions, which are used for numeric processing. We followed this up by looking at string functions that are used for string manipulations and for matching the occurrences of a pattern in a string. Then, we looked at various input/output functions, such as the close() function for closing files and pipes. After this, we looked at the time functions, which can be quite useful when it comes to timestamping or creating log files. We followed this by bit-manipulation functions, which perform bitwise operations on two or more integers. Finally, we looked at how to define and call...