The first three lines were covered in detail in Part 1 of this tutorial. Their function is to initialize the rewriting engine. This specific spider is an email harvester culling addresses from web pages. CondPattern is a regular expression. Before we continue with its specifics, let us take a look at regular expressions and their function in general.
Regular expressions are a means of describing text patterns.
They are used to check if a text pattern is present in any given text. Once determined, this pattern can then be manipulated. Regular expressions are similar to a small, compact programming language in its own right. Regular expressions are construed with the help of these elements and alphanumeric characters. In this case the condition would not be met.