I want to set a file's modification time to the time I got from exif data. To get the time from exif, I found : Graphics.Exif.getTag :: Exif -> String -> IO (Maybe String) To set the file modification time, I found : System.Posix.Files.setFileTimes :: FilePath -> EpochTime -> EpochTime -> IO () Assuming I do find a Time in Exif, I need to convert a String to an EpochTime. - With parseTime I can get a UTCTime. - With utcTimeToPOSIXSeconds I can get a POSIXTime - With a POSIXTime I can more or less get an EpochTime To convert from a UTCTime to EpochTime this typechecks, but I'm not sure it's correct : fromIntegral . fromEnum . utcTimeToPOSIXSeconds $ etime This is part of a function getTime that will return the time from Exif data, if present, otherwise the file's modification time : getTime (path,stat) = do let ftime = modificationTime $ stat err (SomeException _) = return ftime time <- liftIO $ handle err $ do exif <- Exif.fromFile path let getExifTime = MaybeT . liftIO . Exif.getTag exif res <- runMaybeT $ do tmp <- msum . map getExifTime $ [ "DateTimeOriginal", "DateTimeDigitized", "DateTime" ] MaybeT . return . parseTime defaultTimeLocale "%Y:%m:%d %H:%M:%S" $ tmp case res of Nothing -> return ftime Just etime -> return . fromIntegral . fromEnum . utcTimeToPOSIXSeconds $ etime return (path,time) Questions : 1) is there a better way to convert the time ? 2) any general comments on getTime ? Thanks, David.