nptools-0.1: tac.hs

import qualified Data.ByteString.Char8 as S
import System.Environment
import Control.Monad

main :: IO ()
main = do args <- getArgs
          when (null args)  $ tac =<< S.getContents
          forM_ args        $ tac <=< S.readFile
  where tac  = S.putStr . S.intercalate nl . reverse . S.split '\n'
        nl   = S.pack "\n"