++ for the mac portion (although I can't test it), but this was already done in Finding Windows XP CD Key and I also copied that into m Sys::Info where you can just say:

perl -MSys::Info -wle "my$o=Sys::Info->new->os;print for$o->cdkey,$o->
+cdkey(office=>1)"
[download]

however, it'll only create results under windows.