Rread file at path, compress, write to path.gz

compress.hs

{-#  LANGUAGE OverloadedStrings #-}
import System.Environment (getArgs)
import qualified Codec.Compression.GZip as GZ (compress)
import qualified Data.ByteString.Lazy as LB

main :: IO ()
main = do
     -- Get arguments - a path; lift the pure operation 'head' into the IO context
     path <- fmap head getArgs

     -- read the contents of the file in lazily
     contents <- LB.readFile path

     -- write the compressed contents of the file to <path>.gz
     -- lazily
     LB.writeFile (path ++ ".gz") $ GZ.compress contents