Oniguruma (鬼車) is a free and open-source regular expression library that supports a variety of character encodings, written by K. Kosako. The Ruby programming language, in version 1.9, as well as PHP's multi-byte string module, use Oniguruma as their regular expression engine. It is also used in products such as Atom, EDK2 UEFI, GyazMail, Take Command Console, Tera Term, TextMate, SubEthaEdit, jq, Sublime Text and VS Code.