diff --git a/Hish.cabal b/Hish.cabal
--- a/Hish.cabal
+++ b/Hish.cabal
@@ -1,5 +1,5 @@
 Name:                   Hish
-Version:                0.1.0
+Version:                0.1.0.1
 Author:                 Yun-Yan Chi
 Maintainer:             jaiyalas@gmail.com
 License:                BSD3
@@ -27,6 +27,7 @@
   exposed-modules:
         Hish.ANSICode
         Hish.SysInfo
+        Hish.VCS
 
 --
 executable hish
diff --git a/src/Hish/VCS.hs b/src/Hish/VCS.hs
new file mode 100644
--- /dev/null
+++ b/src/Hish/VCS.hs
@@ -0,0 +1,63 @@
+module Hish.VCS
+   (
+   -- * Version Control System
+     VCS   (..)
+   -- ** Git
+   , Git   (..)
+   -- ** Darcs
+   , Darcs (..)
+   ) where
+
+import Text.Regex.TDFA ((=~))
+import qualified Data.String.Utils as S (replace)
+import qualified Data.List as DL (lines)
+
+
+-- | Every version control system provides functions as follows
+--
+class VCS a where
+   -- | tracking ahead
+   vcsAhead :: a -> String -> Maybe String
+   -- | tracking behind
+   vcsBehind :: a -> String -> Maybe String
+   -- | determining the cleanliness of working-tree
+   --
+   --       * __#__ - /clean/ working directory
+   --       * __?__ - /clean/ but existing untracked file
+   --       * __*__ - /dirty/
+   vcsCleanliness :: a -> String -> Maybe String
+   vcsCurrentBranch :: a -> String -> Maybe String
+
+-- | Unit type for presenting Git.
+data Git = Git
+
+instance VCS Git where
+   vcsAhead _ s =
+      case (s =~ "ahead [0-9]+"  :: String) of
+         []    -> Nothing
+         ahead -> Just $ S.replace "ahead " "" ahead
+   vcsBehind _ s =
+      case (s =~ "behind [0-9]+"  :: String) of
+         []    -> Nothing
+         behind -> Just $ S.replace "behind " "" behind
+   vcsCleanliness _ s = let body = tail $ DL.lines s in
+      case body of
+         [] -> Just "#"
+         _  -> let (index,tree) = unzip $ map ((\ (a:b:_)->(a,b)).take 2) body in
+            if ("" == (filter (/='?') tree))
+               then Just "?"
+               else Just "*"
+   vcsCurrentBranch _ = Just
+      . drop 2
+      . head
+      . filter ((=='*').head)
+      . lines
+
+-- | Unit type for presenting Darcs.
+-- /UN-IMPLEMENTED/!
+data Darcs = Darcs
+
+instance VCS Darcs where
+   vcsAhead _ s = return "a"
+   vcsBehind _ s = return "b"
+   vcsCleanliness _ s = return "?"