And once again we are all reminded at just how much a sense of humor is so sorely lacking on this web site, by so many.
To be honest Marine, over the years, I've worked with dozens of Marine Vietnam vet's and I really can't recall ever hearing any of them shout "hooah" in a normal conversation.
Frankly, I never saw the movie that Al Pacino used that expression in either, but when I read your post, that was the first thing that popped into my head too.
Anyway, not being a Marine myself, I always kind of wondered exactly what it meant, and you gave us all an excellent explanation. Thanks.