A Note on Regular Expressions

A regular expression, “regexp”, is a formidable phrase denoting something which is conceptually very simple. A regular expression is an expression that denotes a pattern, coded in a small language designed for just that. The basic special symbols are as follows:

. any one character

* zero or more of the preceding character

^ beginning of line

$ end of line

[a-z] a set of characters [a-z] is the whole lower-case alphabet