Haskell＋ffmpeg hmpeg.hs

import System.Process
import System.Directory
import System.FilePath.Posix
import Control.Monad
import Data.List
doCom x f = createProcess 
    (proc "ffmpeg" ["-i",x,"-sample_fmt", "s16", "-ar", "44100",nf])
    where nf = f:".flac"
filtFile fi = return . filter (\x -> takeExtension x == fi) 
sort' = return . sort 
main = do
    fs <- getCurrentDirectory >>= listDirectory >>= filtFile ".flac" >>= sort' 
    print fs
    zipWithM_ (\x y -> doCom x y) fs ['a' .. 'z']