Regex syntax

This article is currently a stub; it means I'm aware it's short and I probably intend to expand on the subject in the future!

I can never remember which programs use which regex variants, so here's a quick recap sheet.

	grep (GNU)	sed (GNU)	vim	python
capture	\( ... \)	\( ... \)	\( ... \)	( ... )
option	\|	\|	\|	|
word boundary	\< or \>	\< or \>	\< or \>	\b
zero or more	*	*	*	*
zero or more (non-greedy)			\{-}	*?
one or more	\+	\+	\+	+