Dell PowerConnect B-RX Configuration Manual page 859

TABLE 119
Character
_
[ ]
|
( )
If you want to filter for a special character instead of using the special character as described in
Table 26.2 on page 26-45, enter "\" (backslash) in front of the character. For example, to filter on
AS-path strings containing an asterisk, enter the asterisk portion of the regular expression as "\*".
BigIron RX(config-bgp)# ip as-path access-list acl2 deny \*
To use the backslash as a string character, enter two slashes. For example, to filter on AS-path
strings containing a backslash, enter the backslash portion of the regular expression as "\\".
BigIron RX(config-bgp)# ip as-path access-list acl2 deny \\
BigIron RX Series Configuration Guide
53-1001986-01
BGP4 special characters for regular expressions (Continued)
Operation
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. See the example above.
A vertical bar (sometimes called a pipe or a "logical or") separates two
alternative values or sets of values. The AS-path can match one or the other
value. For example, the following regular expression matches on an AS-path that
contains either "abc" or "defg".
(abc)|(defg)
NOTE: The parentheses group multiple characters to be treated as one value. See the
following row for more information about parentheses.
Parentheses allow you to create complex expressions. For example, the following complex
expression matches on "abc", "abcabc", or "abcabcabcdefg", but not on "abcdefgdefg".
((abc)+)|((defg)?)
26
Filtering
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