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diff --git a/src/Commands.hs b/src/Commands.hs
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+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Xmobar.Commands
+-- Copyright   :  (c) Andrea Rossato
+-- License     :  BSD-style (see LICENSE)
+--
+-- Maintainer  :  Jose A. Ortega Ruiz <jao@gnu.org>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- The 'Exec' class and the 'Command' data type.
+--
+-- The 'Exec' class rappresents the executable types, whose constructors may
+-- appear in the 'Config.commands' field of the 'Config.Config' data type.
+--
+-- The 'Command' data type is for OS commands to be run by xmobar
+--
+-----------------------------------------------------------------------------
+
+module Commands
+    ( Command (..)
+    , Exec    (..)
+    , tenthSeconds
+    ) where
+
+import Prelude hiding (catch)
+import Control.Concurrent
+import Control.Exception
+import Data.Char
+import System.Process
+import System.Exit
+import System.IO (hClose)
+import XUtil
+
+class Show e => Exec e where
+    alias :: e -> String
+    alias e    = takeWhile (not . isSpace) $ show e
+    rate  :: e -> Int
+    rate _     = 10
+    run   :: e -> IO String
+    run _      = return ""
+    start :: e -> (String -> IO ()) -> IO ()
+    start e cb = go
+        where go = do
+                run e >>= cb
+                tenthSeconds (rate e) >> go
+
+data Command = Com Program Args Alias Rate
+               deriving (Show,Read,Eq)
+
+type Args    = [String]
+type Program = String
+type Alias   = String
+type Rate    = Int
+
+instance Exec Command where
+    alias (Com p    _    a _)
+        | p /= ""             = if a == "" then p else a
+        | otherwise           = ""
+    start (Com prog args _ r) cb = if r > 0 then go else exec
+        where go = exec >> tenthSeconds r >> go
+              exec = do
+                (i,o,e,p) <- runInteractiveCommand (unwords (prog:args))
+                exit <- waitForProcess p
+                let closeHandles = hClose o >> hClose i >> hClose e
+                case exit of
+                  ExitSuccess -> do
+                            str <- catch (hGetLineSafe o)
+                                         (\(SomeException _) -> return "")
+                            closeHandles
+                            cb str
+                  _ -> do closeHandles
+                          cb $ "Could not execute command " ++ prog
+
+
+-- | Work around to the Int max bound: since threadDelay takes an Int, it
+-- is not possible to set a thread delay grater than about 45 minutes.
+-- With a little recursion we solve the problem.
+tenthSeconds :: Int -> IO ()
+tenthSeconds s | s >= x = do threadDelay y
+                             tenthSeconds (x - s)
+               | otherwise = threadDelay (s * 100000)
+               where y = maxBound :: Int
+                     x = y `div` 100000