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)

String concatenation

There is no specific operation to represent string concatenation. Space is a string concatenation operator that is used to merge two strings.

In the following example, we create three string variables to perform concatenation at different locations. In the statement, str3 contains the concatenated value of str1 and str2. Each print statement performs string concatenation with a static string value and AWK variable:

$ vi string.awk

BEGIN {
OFS=","
str1 = "Good"
str2 = "Morning"
num1 = "10"
str3 = str1 " " str2;
print "Concatenated string is : " str3
num1 = num1+1
print "string to number conversion on addition : " num1
}

$ awk -f string.awk

The output on execution of the preceding code is as follows :

Concatenated string is : Good Morning
string to number conversion...