What does 'Roodow (wrongly spelled, only the sound)' mean?

In Australia, I have met a lot of people saying a word (sound like) 'roudow' to respond (mostly to end, like 'alright' equivalent) a conversation. I have been searching around but haven't got any clue yet due to the spelling. Would you please kindly talk a bit about this for me?

Solution 1:

You might have misheard people saying righto http://australiandictionary.net/righto

I think part of the reason for mishearing in this case, is because Australian pronunciation often involves pronouncing letter t when it is inside a word, like a quiet letter d. That's something in common with American and Canadian accents.

You can learn more from the Consonants section of the article at this link http://en.wikipedia.org/wiki/Australian_English