I try to stay cross platform too, but since his question used tee, I figure there's not much harm in having my solution use it :)

The Tie::Tee example on the link you posted is really slick, and is probably the best solution. You wouldn't have the buffering question since there's only one place where you'd write to STDOUT, it wouldn't be exec-ing an external program, and it would be cross-platform.

/\/\averick