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 arrays. We learned that AWK provides one-dimensional associative arrays (arrays indexed by string values). We also learned how array elements are referenced using arr[index], and that it creates the element if it does not exist. Then we used the for loop to scan through all the individual elements of an array, and tested the array membership using the in operator with the if expression. We used the split function to create an array. We also learned how to delete an individual element or a whole array using the delete command. Finally, we covered how AWK simulates multidimensional arrays by separating subscript values with commas. In this index, values are concatenated into a single string, separated by the value of SUBSEP.

In the next chapter, we will learn about how to do pretty printing in AWK using formatted reports, and we will learn...