Regular Expressions

Overview

The Guardium implementation of regular expressions conforms with POSIX 1003.2. For more detailed information, see the Open Group web site: www.opengroup.org.

This help topic provides instructions for using the Build Regular Expression Tool, and several tables of commonly used special characters and constructs. It does not provide a comprehensive description of how regular expressions are constructed or used. See the web site referenced above for more detailed information.

The important point to keep in mind about pattern matching using regular expressions, is that the search for a match starts at the beginning of a string and stops when the first sequence matching the expression is found.

Using the Build Regular Expression Tool

When an input field requires a regular expression, you can use the Build Regular Expression tool to code and test a regular expression.

To open the Build Regular Expression tool, click the (Regex) button beside the field that will contain the regular expression. If you have already entered anything in the field, it will be copied to the Regular Expression box in the Build Regular Expression panel.

Enter or modify the expression in the Regular Expression box.
To test the expression, enter text in the Text To Match Against box, and then click the Test button:

If the expression contains an error (a missing closing brace, for example), you will be informed with a Syntax Error message.
The Match Found message indicates that your regular expression has found a match in the text that you have entered.
If no match is found, the No Match Found message displays.

We suggest that you repeat the above step a number of times to verify that your regular expression both matches and does not match, as expected for your purpose.
To enter a special character at the end of your expression, you can select it from the Select element list. To enter a special character anywhere else, you will have to type it or copy it there.
When you are done making changes and testing, click the Accept button to close the Build Regular Expression panel and copy the regular expression to the definition panel.

Special Characters and Constructs

The following table provides a summary of the more commonly used special characters and constructs.

Char	How do I ...	Example	Matches	No Match
literal	Match an exact sequence of characters (case sensitive), except for the special characters described below	can	can	Can cab caN
. (dot)	Match any character including carriage return or newline (\n) characters	ca.	can cab	c cb
*	Match zero or more instances of preceding character(s)	Ca*n	Cn Can Caan	Cb Cabn
^	Match string beginning with following character(s)	^C.	Ca	ca a
$	Match string ending with preceding character(s)	C.*n$	Can Cn	Cab
+	Match one or more instances of preceding character(s)	^Ca+n	Can Caan	Cn
?	Match either zero or one instance of preceding character(s)	Ca?n	Cn Can	Caan
\|	Match either the preceding or following pattern	Can \| cab	Can cab	Cab
(x…)	Match the sequence enclosed in parentheses	(Ca)*n	Can XaCan	Cn CCnn
{n}	Match exactly n instances of the preceding character(s)	Ca{3}n	Caaan	Caan Caaaan
{n,}	Match n or more instances of the preceding character(s)	Ca{2,}n	Caan Caaaan	Can Cn
{n,m}	Match from n to m instances of the preceding character(s)	Ca{2,3}n	Caan Caaan	Can Caaaan
[a-ce]	Match a single character in the set, where the dash indicates a contiguous sequence; for example, [0-9] matches any digit	[C-FL]an	Can Dan Lan	Ban
[^a-ce]	Match any character that is NOT in the specified set	[^C-FL]an	aan Ban	Can Dan
[[.char.]]	Match the enclosed character or the named character from the Named Characters Table, below	[[.~.]]an or [[.tilde.]]an	~an	@an
[[:class:]]	Match any character in the specified character class, from the Character Classes Table, below	[[:alpha:]]+	abc	ab3

Named Characters Table (English)

The following table describes the standard character names that can be used within regular expression bracket pairs ([[.char]] - see above). Character names are location specific, so non-English versions of Guardium may use a different set of character names.

Name	Value
NUL	\0
SOH	\001
STX	\002
ETX	\003
EOT	\004
ENQ	\005
ACK	\006
BEL	\007
alert	\007
BS	\010
backspace	\b
HT	\011
tab	\t
LF	\012
newline	\n
VT	\013
vertical-tab	\v
FF	\014
form-feed	\f
CR	\015
carriage-return	\r
SO	\016
SI	\017
DLE	\020
DC1	\021
DC2	\022
DC3	\023
DC4	\024
NAK	\025
SYN	\026
ETB	\027
CAN	\030
EM	\031
SUB	\032
ESC	\033
IS4	\034
FS	\034
IS3	\035
GS	\035
IS2	\036
RS	\036
IS1	\037
US	\037
space	' '
exclamation-mark	!
quotation-mark	"
number-sign	#
dollar-sign	$
percent-sign	%
ampersand	&
apostrophe	\'
left-parenthesis	(
right-parenthesis	)
asterisk	*
plus-sign	+
comma	,
hyphen	-
hyphen-minus	-
period	.
full-stop	.
slash	/
solidus	/
zero	0
one	1
two	2
three	3
four	4
five	5
six	6
seven	7
eight	8
nine	9
colon	:
semicolon	;
less-than-sign	<
equals-sign	=
greater-than-sign	>
question-mark	?
commercial-at	@
left-square-bracket	[
backslash	\\
reverse-solidus	\\
right-square-bracket	]
circumflex	^
circumflex-accent	^
underscore	_
low-line	_
grave-accent	`
left-brace	{
left-curly-bracket	{
vertical-line	\|
right-brace	}
right-curly-bracket	}
tilde	~
DEL	177
NULL	0

Named Character Class Table (English)

The following table describes the standard character classes that you can reference within regular expression bracket pairs ([[:class:]] - see above). Note that character classes are location specific, so non-English versions of Guardium may use a different set of character names.

Class	Characters Included
alnum	Alphanumeric (a-z, A-Z, 0-9)
alpha	Alphabetic (a-z, A-Z)
blank	Whitespace (blank, line feed, carriage return)
cntrl	Control
digit	0-9
graph	Graphics
lower	Lowercase alphabetic (a-z)
print	Printable characters
punct	Punctuation characters
space	Space, tab, newline, and carriage return
upper	Uppercase alphabetic
xdigit	Hexadecimal digit (0-9, a-f)

Regular Expression Examples

You can copy and paste any of the expressions from the right-hand column to a field requiring a regular expression. When using any of these examples, we strongly suggest that you experiment by using it in the Build Regular Expression tool, entering a variety of matching and non-matching values, so that you understand exactly what is being matched by the expression.

Description	Regular Expression
Social Security Number (must have hyphens)	[0-9]{3}-[0-9]{2}-[0-9]{4}
Phone Number (North America - Matches 3334445555, 333.444.5555, 333-444-5555, 333 444 5555, (333) 444 5555, and all combinations thereof)	$?[0-9]{3}$?[-. ]?[0-9]{3}[-. ]?[0-9]{4}
Postal Code (Canada)	[ABCEGHJKLMNPRSTVXY][0-9][A-Z] [0-9][A-Z][0-9]
Postal Code (UK)	[A-Z]{1,2}[0-9][A-Z0-9]? [0-9][ABD-HJLNP-UW-Z]{2}
Zip Code (US) (5 digits required, hyphen followed by four digits optional)l	[0-9]{5}(?:-[0-9]{4})?
Credit Card Numbers	[0-9]{4}[-, ]?[0-9]{4}[-, ]?[0-9]{4}[-, ]?[0-9]{4}