Brocade Virtual ADX Switch and Router Guide (Supporting ADX v03.1.00) - Manual (Page 262)

248 Brocade Virtual ADX Switch and Router Guide
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Filtering
8
Special characters
When you enter a single-character expression or a list of characters, you also can use the special
characters listed in
Table 36 . The description for each character includes an example. Some
special characters must be placed in front of the characters they control and others must be
placed after the characters they control. The examples show where to place the special character.
TABLE 36 BGP4 special characters for regular expressions
Character Operation
. The period matches on any single character, including a blank space. For example, the following
regular expression matches for “aa”, “ab”, “ac”, and so on, but not just “a”.
a.
* The asterisk matches on zero or more sequences of a pattern. For example, the following regular
expression matches on an AS-path that contains the string “1111” followed by any value:
1111*
+ The plus sign matches on one or more sequences of a pattern. For example, the following regular
expression matches on an AS-path that contains a sequence of “g”s, such as “deg”, “degg”,
“deggg”, and so on:
deg+
? The question mark matches on zero occurrences or one occurrence of a pattern. For example,
the following regular expression matches on an AS-path that contains “dg” or “deg”:
de?g
^ A caret (when not used within brackets) matches on the beginning of an input string. For
example, the following regular expression matches on an AS-path that begins with “3”:
^3
$ A dollar sign matches on the end of an input string. For example, the following regular expression
matches on an AS-path that ends with “deg”:
deg$
_ An underscore matches on one or more of the following:
•
, (comma)
•
{ (left curly brace)
•
} (right curly brace)
•
( (left parenthesis)
•
) (right parenthesis)
•
The beginning of the input string
•
The end of the input string
•
A blank space
For example, the following regular expression matches on “100” but not on “1002”, “2100”, and
so on.
_100_
[ ] Square brackets enclose a range of single-character patterns. For example, the following regular
expression matches on an AS-path that contains “1”, “2”, “3”, “4”, or “5”:
[1-5]
You can use the following expression symbols within the brackets. These symbols are allowed
only inside the brackets:
•
^ – The caret matches on any characters except the ones in the brackets. For example, the
following regular expression matches on an AS-path that does not contain “1”, “2”, “3”, “4”,
or “5”:
[^1-5]
•
- The hyphen separates the beginning and ending of a range of characters. A match occurs
if any of the characters within the range is present. Refer to the example above.