bytestring.hs

import System.Environment
import System.Directory
import System.IO
import Control.Exception
import qualified Data.ByteString.Lazy as B

main :: IO ()
main = do
  (fileName : fileName2: _) <- getArgs
  copy fileName fileName2

copy :: String -> String -> IO()
copy source dest = do
  contents <- B.readFile source
  bracketOnError
    (openTempFile "." "temp")
    (\ (tempName, tempHandle) -> do
        hClose tempHandle
        removeFile tempName)
    (\ (tempName, tempHandle) -> do
        B.hPutStr tempHandle contents
        hClose tempHandle
        renameFile tempName dest)