Regular expression operators

The rules for using regular expression operators are:

• When making a query, the asterisk (*), period (.) and question mark (?) behave as they do in Windows. The asterisk (*) matches any number of characters. The period (.) matches end of string. The question mark (?) matches any single character.
• Any character except asterisk (*), period (.), question mark (?), and vertical bar (|) defaults to matching itself.
• Regular expressions can be enclosed in matching quotation marks (" "), and must be enclosed in quotation marks if they contain a space or closing parenthesis ( ) ).

When preceded by a vertical bar (|), the following characters have special meaning:

Character	Description
(	Opens a group. Must be followed by a matching closing parenthesis ( ) ).
)	Closes a group. Must be preceded by a matching opening parenthesis ( ( ).
[	Opens a character class. Must be followed by a matching closing bracket (]).
]	Closes a character class. Must be preceded by a matching opening bracket ([).
{	Opens a counted match. Must be followed by a matching closing brace (}).
}	Closes a counted match. Must be preceded by a matching opening brace ({).
,	Separates OR clauses.
*	Matches zero or more occurrences of the preceding expression.
?	Matches zero or one occurrence of the preceding expression.
+	Matches one or more occurrences of the preceding expression.
All else	Matches itself.

Brackets

Between brackets ([ ]), the following characters have special meaning:

Character	Description
^	Must be the first character. Matches everything but following classes.
]	Closes the class. May only be preceded by a caret (^).
-	Range operator. Preceded and followed by other characters.
All else	Matches itself, begins, or ends a range.

Braces

Between braces ({ }), the following meanings apply.

Character	Description
m	Matches exactly m occurrences of the preceding expression (0< m < 256).
m,	Matches at least m occurrences of the preceding expression (1< m < 256).
m,n	Matches between m and n occurrences of the preceding expression, inclusive (0 < m < 256, 0 < n < 256).

To match the asterisk (*), the period (.), and the question mark (?), enclose them in brackets. For example, to search for "hello?", type hello[?] in the query.