Basics of Pattern Matching & Substitutions with Perl ...

Regular Expressions. A regular expression is a string of characters that matches a pattern of some kind. As a simple example, we could say that any string that consists of 0s and 1s constitutes a regular expression (this would actually be the set of strings that are binary numbers, such as 000, 101, 11111, 0, 1010101010, etc). ................
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