or download this
use warnings;
use strict;
...
In '51:50:47:42', I've seen '51:50:47'/'51:50'/'50:47' before, '42' is
+ new.
I have not seen '37:30' before, it is new.
In '51:50:47:42:37:30', I've seen '51:50:47:42'/'51:50:47'/'50:47:42'/
+'51:50'/'50:47'/'47:42'/'37:30' before, nothing is new.