History[edit | edit source]
Regular expressions originated in 1956 when an American Mathematician Stephen Kleene was working on formalizing Regular languages. Computer Science borrows most of the good ideas from Mathematics. Mathematicians have the biggest impact on computer science. The regular language is any language that can be expressed using regular expressions. The first application of regular expression was an editor named QED developed by Ken Thompson. Regular expressions are present in every programming language and most of the *nix tools make use of them like find, grep, etc.