Special Characters

. any character except a newline

^ start of string

$ end of string

* 0 or more repetition

+ 1 or more repetition

? 0 or 1 repetition

all greedy

{m} pecifies that exactly m copies of the previous RE should be matched example: a{6} = aaaaaaa

{m,n} m to n repetations of the previous

\ escape special characters

[] indicate a set of characters example [amk] will match ‘a’, ‘m’, or ‘k’

| example A|B will match either A or B from left to right

\d [0-9]

\D nondigital char

\s any space char

\S any char other than space

\w any numalpha n \W any char other than numalpha