Cisco ASA 5506-X Configuration Manual page 144

Configure Regular Expressions
Table 6-3
Character Description
*
+
{x} or {x,} Minimum repeat quantifier
[abc]
[^abc]
[a-c]
""
^
\
char
\r
\n
\t
\f
\xNN
\NNN
Procedure
Test a regular expression to make sure it matches what you think it will match.
Step 1
Cisco ASA Series Firewall CLI Configuration Guide
6-16
Regular Expression Metacharacters (continued)
Asterisk
Plus
Character class
Negated character class
Character range class
Quotation marks
Caret
Escape character
Character
Carriage return
Newline
Tab
Formfeed
Escaped hexadecimal number
Escaped octal number
Chapter 6 Getting Started with Application Layer Protocol Inspection
Notes
A quantifier that indicates that there are 0, 1 or any
number of the previous expression. For example, lo*se
matches lse, lose, loose, and so on.
A quantifier that indicates that there is at least 1 of the
previous expression. For example, lo+se matches lose
and loose, but not lse.
Repeat at least x times. For example, ab(xy){2,}z
matches abxyxyz, abxyxyxyz, and so on.
Matches any character in the brackets. For example,
[abc] matches a, b, or c.
Matches a single character that is not contained within
the brackets. For example, [^abc] matches any character
other than a, b, or c. [^A-Z] matches any single
character that is not an uppercase letter.
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].
Preserves trailing or leading spaces in the string. For
example, " test" preserves the leading space when it
looks for a match.
Specifies the beginning of a line.
When used with a metacharacter, matches a literal
character. For example, \[ matches the left square
bracket.
When character is not a metacharacter, matches the
literal character.
Matches a carriage return 0x0d.
Matches a new line 0x0a.
Matches a tab 0x09.
Matches a form feed 0x0c.
Matches an ASCII character using hexadecimal (exactly
two digits).
Matches an ASCII character as octal (exactly three
digits). For example, the character 040 represents a
space.