gistfile1.hs

import System.Environment
import System.IO
import Control.Monad (when)

matchGlob :: String -> String -> Bool
matchGlob = undefined

main :: IO ()
main = do
  args <- getArgs
  case length args of
    0 -> putStrLn "usage: glob <glob-pattern> [file 1] [file 2] ... [file N]"
    1 -> stdinglob (args !! 0)
    _ -> mapM_ (fileglob (args !! 0)) (tail args)

  where
    stdinglob glob = do
      string <- getLine
      when (matchGlob glob string) $ putStrLn string
      stdinglob glob

    fileglob glob fileName = do
      withFile fileName ReadMode $ \fileHandle -> do
        contents <- hGetContents fileHandle
        let matches = filter (matchGlob glob) . words $ contents
        mapM_ (\match -> putStrLn $ fileName ++ ": " ++ match) matches