In This Section: |
This table shows the Check Point implementation of standard regular expression metacharacters.
Metacharacter |
Name |
Description |
---|---|---|
\ |
Backslash |
escape metacharacters non-printable characters character types |
[ ] |
Square Brackets |
character class definition |
( ) |
Parenthesis |
sub-pattern, to use metacharacters on the enclosed string |
{min[,max]} |
Curly Brackets |
min/max quantifier {n} - exactly n occurrences {n,m} - from n to m occurrences {n,} - at least n occurrences |
. |
Dot |
match any character |
? |
Question Mark |
zero or one occurrences (equals {0,1}) |
* |
Asterisk |
zero or more occurrences of preceding character |
+ |
Plus Sign |
one or more occurrences (equals {1,}) |
| |
Vertical Bar |
alternative |
^ |
Circumflex |
anchor pattern to beginning of buffer (usually a word) |
$ |
Dollar |
anchor pattern to end of buffer (usually a word) |
- |
hyphen |
range in character class |
To use non-printable characters in patterns, escape the reserved character set.
Character |
Description |
---|---|
\a |
alarm; the BEL character (hex code |
\cX |
"control-X", where X is any character |
\e |
escape (hex code |
\f |
formfeed (hex code |
\n |
newline (hex code |
\r |
carriage return (hex code |
\t |
tab (hex code |
\ddd |
character with octal code |
\xhh |
character with hex code |
To specify types of characters in patterns, escape the reserved character.
Character |
Description |
---|---|
\d |
any decimal digit [0-9] |
\D |
any character that is not a decimal digit |
\s |
any whitespace character |
\S |
any character that is not whitespace |
\w |
any word character (underscore or alphanumeric character) |
\W |
any non-word character (not underscore or alphanumeric) |
Select URLs are defined as Regular Expression only if the application or site URL is entered as a regular expression using the correct syntax.
The meaning of the asterisk ( * ) depends on its use.
For example, to block a domain that ends with "example.com" (such as www.example.com):
Regular Expression |
|
|
Wildcard |
|
Important! If you use this string as a regular expression, policy install fails. The gateway cannot resolve the regular expression to a URL, because there is no preceding character to find. |
More examples of regular expressions:
To match subdomains of mydomain.com: (^|.*\.)mydomain\.com
To match domain and subdomains of mydomain.com: (^|.*\.)*mydomain\.com