^ Start of string
$ End of string
[] Range of characters
– Used to specify a range (i.e. [a-z])
() Local grouping
. Any single character
* Zero or more instances
+ One ore more instances
? Zero or one instance
\ the \ matches the charcter
– Comma, open or clase brace, open or close paranthese, start or end of string, or space
Some examples matches:
.* Anything
^$ Local originated routes
^200_ Learned from AS 200
_200$ Originated in AS 200
_100_ Any instance of AS 100
^[0-9]+(_[0-9])?$ Directly connected AS’s and their customers
^\(.*\)$ Routes originated in confederation peers
^(\(.*\))?$ Locally originated and/or routes originated in confederation peers