Book Image

Learning AWK Programming

By : Kalkhanda
5 (1)
Book Image

Learning AWK Programming

5 (1)
By: 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)

Pretty printing with the printf statement

Most of the programs we have written so far have used the print command to display the output. Sometimes, the columns don't line up properly with the print statement. So, to have more control over output formatting we have to use a printf statement. It is very flexible and is used to generate formatted output. It is similar to the C language's printf statement, with only one exception: the absence of a * format specifier. Like the print statement, it can be used with parentheses or without parentheses, as follows:

printf format, expr1, expr2, expr3 ……… exprn
printf ( format, expr1, expr2, expr3 ……… exprn )

The main difference between print and printf is the format argument. It is an expression whose value is taken as a string; it specifies how to output each of the other arguments. It...