Add version command to show git-annex version as well as repository version information.

Command/Version.hs

@@ -0,0 +1,34 @@
+{- git-annex command
+ -
+ - Copyright 2010 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Command.Version where
+
+import Control.Monad.State (liftIO)
+import Data.String.Utils
+
+import Command
+import qualified SysConfig
+import Version
+import Upgrade
+
+command :: [Command]
+command = [Command "version" paramNothing seek "show versions"]
+
+seek :: [CommandSeek]
+seek = [withNothing start]
+
+start :: CommandStartNothing
+start = do
+	liftIO $ putStrLn $ "git-annex version: " ++ SysConfig.packageversion
+	v <- getVersion
+	liftIO $ putStrLn $ "local repository version: " ++ v
+	liftIO $ putStrLn $ "default repository version: " ++ defaultVersion
+	liftIO $ putStrLn $ "supported repository versions: " ++ vs supportedVersions
+	liftIO $ putStrLn $ "upgrade supported from repository versions: " ++ vs upgradableVersions
+	return Nothing
+	where
+		vs l = join " " l