@Sidewinder Yep. You could say "Oi!" to someone touching your expensive car as a way to tell them to scram, or you could say "Oi!" to your boys as a way of saying hi.
it's commonly used here in england too. "Oi" is used to get people's attention. like say your friend is walking by, you call their name and they don't respond. you'd say "Oi" a little louder. it's kinda seen as rude if you're talking to someone you don't know. it's very informal obviously.
@Bluedreamz Just remember that Australia is 90% of the land area of the US. It’s the same distance from Boston to LA as it is from Brisbane to Perth and there is a LOT to see in Australia. So pick your city or state and give yourself a couple of months to travel and experience Australia. You have the tropics of North Queensland or the deserts of Western Australia or the big city bustle of Sydney.