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Introduction to Regular Expressions

The term regular expression refers to a special way of defining, searching for, and modifying patterns in text. At the simplest level, you can think of a regular expression as being simply a literal piece of text, like the characters in the word ``cat'' or the string ``0.0''. At a more complex level, they describe patterns such as ``the word 'cat' followed by one or more blanks, followed by any word ending in the string 'ed' ''. Regular expressions are found in many programs, with varying capabilities, but the implementation of regular expressions in perl is considered by most people to be the best and most complete.

Perl provides operators to let you check to see if a regular expression occurs in a particular piece of text, as well as to modify the text based on the presence of a regular expression. While it takes some time to fully appreciate and use all the features of regular expressions found in perl, you can start using simple regular expressions in your perl programs right away, and learn the complexities of regular expressions over time.


next up previous contents
Next: Operators to Work with Up: Regular Expressions Previous: Regular Expressions   Contents
Phil Spector 2002-10-18