[Haskell-beginners] lazy IO by example

Hi community, In the following code, the main function only wants to print the first 5 numbers of a huge list. But since the computation is not lazy, this doesn't work in a satisfactory way. content :: Int -> IO [Int] content i = do fs <- files i ds <- directories i fss <- mapM content ds return $ fs ++ concat fss files i = return [1..i] directories i = return [1..i-1] main = content 1000000 >>= print . take 5 Now I'd like to know if it's possible to make this "IO" lazy, using unsafeInterleaveIO. I tried to do it, failed. Perhaps someone can help. I guess another weakness of this code is the bad performance of "dfs ++ concat fss", but currently I don't care about that. Thanks for any help Tim