Cisco 500 Series, Configuration Manual

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21-8
Cisco Security Appliance Command Line Configuration Guide
OL-12172-03
Chapter 21 Using Modular Policy Framework
Configuring Special Actions for Application Inspections
To test and create a regular expression, perform the following steps:
Step 1
To test a regular expression to make sure it matches what you think it will match, enter the following
command:
hostname(config)# test regex input_text regular_expression
Where the input_text argument is a string you want to match using the regular expression, up to 201
characters in length.
The regular_expression argument can be up to 100 characters in length.
Use Ctrl+V to escape all of the special characters in the CLI. For example, to enter a tab in the input
text in the test regex command, you must enter test regex "test[Ctrl+V Tab]" "test\t" .
If the regular expression matches the input text, you see the following message:
INFO: Regular expression match succeeded.
If the regular expression does not match the input text, you see the following message:
INFO: Regular expression match failed.
Step 2
To add a regular expression after you tested it, enter the following command:
[ a - c ] Character range class Matches any character in the range. [a-z] matches any
lowercase letter. You can mix characters and ranges:
[abcq-z] matches a, b, c, q, r, s, t, u, v, w, x, y, z, and so
does [ a-cq-z] .
The dash (-) character is literal only if it is the last or the
first character within the brackets:
[abc-] or [-abc] .
"" Quotation marks Preserves trailing or leading spaces in the string. For
example,
" test" preserves the leading space when it
looks for a match.
^ Caret Specifies the beginning of a line.
\ Escape character When used with a metacharacter, matches a literal
character. For example,
\[ matches the left square
bracket.
char Character When character is not a metacharacter, matches the
literal character.
\r Carriage return Matches a carriage return 0x0d.
\n Newline Matches a new line 0x0a.
\t Tab Matches a tab 0x09.
\f Formfeed Matches a form feed 0x0c.
\x NN Escaped hexadecimal number Matches an ASCII character using hexadecimal (exactly
two digits).
\ NNN Escaped octal number Matches an ASCII character as octal (exactly three
digits). For example, the character 040 represents a
space.
Table 21-1 regex Metacharacters (continued)
Character Description Notes