Cisco Cisco Web Security Appliance S170 사용자 가이드

 describes characters that are commonly used to form regular expressions: 

To match the literal version of any of the special characters, the character must be preceded by a 
backslash “\”. For example, to exactly match a period “.” the regular expression must use “\.” as in 
“\.example\.com”. However, the appliance does not support using a backward slash to escape a forward 
slash. If you need to use a forward slash in a regular expression, type the forward slash without a 
backward slash.

.

Matches a single character.

*

Matches zero or more occurrences of the preceding regular expression. 

For example:

[0-9]* matches any number of digits

“.*” matches any arbitrary string of characters

^

Matches the beginning of a line as the first character of a regular expression.

$

Matches the end of a line as the last character of a regular expression.

+

Matches one or more occurrences of the preceding regular expression.

?

Matches zero or one occurrence of the preceding regular expression.

|

Matches the preceding regular expression or the following regular expression. For 
example:

x|y matches either x or y

abc|xyz matches either of the strings abc or xyz

[ ]

Matches the characters or digits that are enclosed within the brackets. 

For example:

[a-z] matches any character between a and z

[r-u] matches any of the characters r, s, t, or u

[0-3] matches any of the single digits 0, 1, 2, 3

{ }

Specifies the number of times to match the previous pattern. 

For example:

D{1,3} matches one to three occurrences of the letter D

( )

Group characters in a regular expression.

For example:

(abc)* matches abc or abcabcabc

“...”

Literally interprets any characters enclosed within the quotation marks.

\

Escape character.