Bracketing: Matching a Set of Characters

Bracketing: Matching a Set of Characters

Brackets enable you to specify a range of single characters. For example:

  ip as-path access-list 22 permit ^85[0123459]$  

This filter matches AS_PATHs with any single AS number 850, 851, 852, 853, 854, 855, or 859.

If the range of characters is contiguous, you can specify just the beginning and end character in the sequence:

  ip as-path access-list 23 permit ^85[0-5]$  

This filter matches the same group of AS numbers as the preceding filter, with the exception of 859.