prime.hs

import System.Environment (getArgs)

primes = filterPrime [2..]
    where filterPrime (p:xs) = p : filterPrime [x | x <- xs, x `mod` p /= 0]

main :: IO ()
main = do
    args <- getArgs
    if length args < 1
    then
      putStrLn "Usage: ./prime N"
    else do
      print $ take (read $ args !! 0) primes