Use parentheses to create the string matches you need in regular expressions. Parentheses allows you to use pipes for multiple matches.

The Linux utility sed provides a great way to substitute text strings in a file. Using the "s" option and by listing the current string and the string to use as the new text allows sed to perform this task.

When you want to reuse functions in multiple scripts you can create a library which allows you to access those created functions.

The Linux utility nl is an easy tool to use to number lines in scripts or flexible enough to create headers, body and footers in your documents.

Using a for loop to examine a series of IP Addresses to use in a firewall script to block Zombie networks.

The awk file can be modified to include a BEGIN section and an END section that allows you to perform tasks before and after the records are processed.

By performing these basic commands you will begin to see the power and flexibility of the Linux utility awk. This exercise is designed to start you down the path of using awk.

This tutorial describes how awk can use operators to increment or decrement as well as other arithmetic functions. awk uses four arithmetic functions:
+ addition
- subtraction
* multiplication and
/ division.