Regular Expressions
-------------------

What?
-----
x		an x (literal)
.		any character
[aeiou]		1 of these char's 
			(character class)
[a-n]		1 of these char's 
			(ASCII range character class)
[^aeiou]	NOT 1 of these char's (negative char. class)
\d		a digit (class shorthand)
\D		NOT a digit (negative class)
\w		a word character (class shorthand)
\W		NOT a word character (negative class)
\s		a "whitespace" character (class shorthand)
\S		NOT a "whitespace" character (negative class)

How many?
---------
x*		0 or more x's
x+		1 or more x's
x?		0 or 1 x
x{4,8}		as few as 4 or as many as 8 x's
x{10,}		10 or more x's
x{75}		exactly 75 x's

Grouping
--------
(bamm)+		1 or more 'bamm'

Alternation
-----------
this|that	'this' or 'that'

Where? (Anchors)
----------------
^x		x at the beginning
x$		x at the end
\b		a word boundary
\B		NOT a word boundary

Back reference
--------------
(b[aio]m)\1	'bambam' or 'bimbim' or 'bombom' 
		(NOT 'bimbam', etc.)