Regular Expressions

Some people, when confronted with a problem, think "I know, I’ll use regular expressions." Now they have two problems.
Jamie Zawinski

Symbol	Matches
. (dot	Any single character
\d	Any single digit
[A-Z]	Any character between A and Z (upercase)
[a-z]	Any character between a and z (lowercase)
[A-Za-z]	Any character between a and z (case-insensitive)
+	One or more of the previous expression
[^/]+	One or more characters until (and not including) a forward slash
?	Zero or one of the previous expression
*	Zero or more of the previous expression
{1,3}	Between one and three (inclusive) of the previous expression