Doug and Buffalo Bob

Sean Straw suggested to Doug Hagen,

| * ^From:.*BOB@(VAXHOST\.|UNIXHOST\.|)BUFFALO\.EDU

That would certainly work.  Personally, though, I don't like the technique of
alternating with null and would feel more comfortable with this equivalent
syntax, using the question mark:

  * ^From:.*BOB@(VAXHOST\.|UNIXHOST\.)?BUFFALO\.EDU

This is equivalent as well, but it is harder to read and probably slower to
run:

  * ^From:.*BOB@((VA|UNI)XHOST\.)?BUFFALO\.EDU