PCRE
Perl Compat. Regular Expression
[a-c]
Match a range from a to c
\w
Matches all letters, numbers, and underscore [A-Za-z0-9_]
a{3}
Match exactly three a’s
a{1,3}
Match exactly 1-3 a’s
[wxy]{5}
Five characters which can be w, x, or y
.{2,6}
2-6 of anything
*
0 or more of a character
+
1 or more of a character
[abc]+
1 or more a, b, or c
?
Preceding character is optional
Match “starts with”
$
Matches “ends with”
|
Or