diff --git a/b9.cabal b/b9.cabal
--- a/b9.cabal
+++ b/b9.cabal
@@ -1,5 +1,5 @@
 name:                b9
-version:             0.5.44
+version:             0.5.46
 
 synopsis:            A tool and library for building virtual machine images.
 
@@ -98,6 +98,7 @@
                    , B9.Vm
                    , B9.VmBuilder
                    , Data.ConfigFile.B9Extras
+                   , System.IO.B9Extras
   other-modules:   Paths_b9
   -- other-extensions:
   build-depends:     ConfigFile >= 1.1.4
diff --git a/src/cli/Main.hs b/src/cli/Main.hs
--- a/src/cli/Main.hs
+++ b/src/cli/Main.hs
@@ -7,7 +7,7 @@
 
 main :: IO ()
 main = do
-    b9Opts  <- parseCommandLine
+    b9Opts <- parseCommandLine
     applyB9RunParameters b9Opts
 
 
@@ -40,7 +40,7 @@
         (helper <*> (B9RunParameters <$> globals <*> cmds <*> buildVars))
         (  fullDesc
         <> progDesc
-               "Build and run VM-Images inside LXC containers. Custom arguments follow after '--' and are accessable in many strings in build files  trough shell like variable references, i.e. '${arg_N}' referes to positional argument $N.\n\nRepository names passed to the command line are looked up in the B9 configuration file, which is per default located in: '~/.b9/b9.conf'"
+               "Build and run VM-Images inside LXC containers. Custom arguments follow after '--' and are accessable in many strings in build files  trough shell like variable references, i.e. '${arg_N}' referes to positional argument $N.\n\nRepository names passed to the command line are looked up in the B9 configuration file, which is per default located in: '~/.b9/b9.conf'. The current working directory is used as ${buildDirRoot} if not otherwise specified in the config file, or via the '-b' option."
         <> headerDoc (Just b9HelpHeader)
         )
     )
@@ -78,14 +78,8 @@
                 )
         <*> optional
                 ( strOption
-                    (  help "Output file for a command/timing profile"
-                    <> long "profile-file"
-                    <> metavar "FILENAME"
-                    )
-                )
-        <*> optional
-                ( strOption
-                    (  help "Root directory for build directories"
+                    (  help
+                          "Root directory for build directories. If not specified '.'. The path will be canonicalized and stored in ${buildDirRoot}."
                     <> short 'b'
                     <> long "build-root-dir"
                     <> metavar "DIRECTORY"
@@ -122,13 +116,12 @@
         -> Bool
         -> Maybe FilePath
         -> Maybe FilePath
-        -> Maybe FilePath
         -> Bool
         -> Bool
         -> Maybe FilePath
         -> Maybe String
         -> B9ConfigOverride
-    toGlobalOpts cfg verbose quiet logF profF buildRoot keep notUnique mRepoCache repo
+    toGlobalOpts cfg verbose quiet logF buildRoot keep notUnique mRepoCache repo
         = let minLogLevel = if verbose
                   then Just LogTrace
                   else if quiet then Just LogError else Nothing
@@ -138,8 +131,6 @@
                       .~ minLogLevel
                       &  logFile
                       .~ logF
-                      &  profileFile
-                      .~ profF
                       &  buildDirRoot
                       .~ buildRoot
                       &  keepTempDirs
@@ -214,7 +205,9 @@
            )
     <> command
            "list"
-           (info (pure (void runListSharedImages)) (progDesc "List shared images."))
+           ( info (pure (void runListSharedImages))
+                  (progDesc "List shared images.")
+           )
     <> command
            "add-repo"
            ( info (runAddRepo <$> remoteRepoParser)
@@ -222,9 +215,8 @@
            )
     <> command
            "reformat"
-           ( info
-               ( runFormatBuildFiles    <$> buildFileParser              )
-               (progDesc "Re-Format all build files.")
+           ( info (runFormatBuildFiles <$> buildFileParser)
+                  (progDesc "Re-Format all build files.")
            )
     )
 
diff --git a/src/lib/B9.hs b/src/lib/B9.hs
--- a/src/lib/B9.hs
+++ b/src/lib/B9.hs
@@ -43,7 +43,7 @@
 import Text.Printf as X (printf)
 import Data.Version as X
 import B9.B9Monad as X
-import Data.ConfigFile.B9Extras as X
+import System.IO.B9Extras as X
 import B9.B9Config as X
 import B9.ExecEnv as X
 import B9.DiskImages as X
@@ -101,26 +101,24 @@
 runPush name = localRuntimeConfig (keepTempDirs .~ False) $ run $ do
   conf <- getConfig
   if isNothing (conf ^. repository)
-    then
-      errorExitL
-        "No repository specified! Use '-r' to specify a repo BEFORE 'push'."
-    else
-      pushSharedImageLatestVersion name
+    then errorExitL
+      "No repository specified! Use '-r' to specify a repo BEFORE 'push'."
+    else pushSharedImageLatestVersion name
 
 -- | Either pull a list of available 'SharedImageName's from the remote
 -- repository if 'Nothing' is passed as parameter, or pull the latest version
 -- of the image from the remote repository. Note: The remote repository is
 -- specified in the 'B9Config'.
 runPull :: MonadIO m => Maybe SharedImageName -> B9ConfigAction m ()
-runPull mName =
-  localRuntimeConfig (keepTempDirs .~ False)
-                     (run (pullRemoteRepos >> maybePullImage))
-  where maybePullImage =
-          mapM_ (\name -> pullLatestImage name >>= failIfFalse name) mName
-        failIfFalse _name True =
-          return ()
-        failIfFalse name False =
-          errorExitL (printf "failed to pull: %s" (show name))
+runPull mName = localRuntimeConfig (keepTempDirs .~ False)
+                                   (run (pullRemoteRepos >> maybePullImage))
+ where
+  maybePullImage = mapM_
+    ( \name ->
+      pullLatestImage name >>= maybe (failPull name) (const (return ()))
+    )
+    mName
+  failPull name = errorExitL (printf "failed to pull: %s" (show name))
 
 -- | Execute an interactive root shell in a running container from a
 -- 'SharedImageName'.
@@ -159,15 +157,16 @@
         putStrLn "DELETING FILES:"
         putStrLn (unlines filesToDelete)
         mapM_ removeIfExists filesToDelete
-  obsoleteSharedmages :: [SharedImage] -> [SharedImage]
-  obsoleteSharedmages =
-    concatMap (tail . reverse) . filter ((> 1) . length) . groupBy
-      ((==) `on` siName)
-  removeIfExists :: FilePath -> IO ()
-  removeIfExists fileName = removeFile fileName `catch` handleExists
    where
-    handleExists e | isDoesNotExistError e = return ()
-                   | otherwise             = throwIO e
+    obsoleteSharedmages :: [SharedImage] -> [SharedImage]
+    obsoleteSharedmages =
+      concatMap (tail . reverse) . filter ((> 1) . length) . groupBy
+        ((==) `on` sharedImageName)
+    removeIfExists :: FilePath -> IO ()
+    removeIfExists fileName = removeFile fileName `catch` handleExists
+     where
+      handleExists e | isDoesNotExistError e = return ()
+                     | otherwise             = throwIO e
 
 -- | Clear the shared image cache for a remote. Note: The remote repository is
 -- specified in the 'B9Config'.
@@ -195,11 +194,10 @@
       allRepos <- getRemoteRepos
       if isNothing remoteRepo
         then liftIO $ do
-          putStrLn "Showing local shared images only."
-          putStrLn
-            "\nTo view the contents of a remote repo add \n\
-                        \the '-r' switch with one of the remote \n\
-                        \repository ids."
+          putStrLn "Showing local shared images only.\n"
+          putStrLn "To view the contents of a remote repo add"
+          putStrLn "the '-r' switch with one of the remote"
+          putStrLn "repository ids."
         else liftIO $ putStrLn
           (  "Showing shared images on: "
           ++ remoteRepoRepoId (fromJust remoteRepo)
diff --git a/src/lib/B9/ArtifactGenerator.hs b/src/lib/B9/ArtifactGenerator.hs
--- a/src/lib/B9/ArtifactGenerator.hs
+++ b/src/lib/B9/ArtifactGenerator.hs
@@ -179,7 +179,7 @@
 getArtifactSourceFiles (FromContent   f _) = [f]
 getArtifactSourceFiles (FromFile      f _) = [f]
 getArtifactSourceFiles (IntoDirectory pd as) =
-    (pd</>) <$> (as >>= getArtifactSourceFiles)
+    (pd </>) <$> (as >>= getArtifactSourceFiles)
 getArtifactSourceFiles (FromDirectory _ as) = as >>= getArtifactSourceFiles
 getArtifactSourceFiles (SetPermissions _ _ _ as) =
     as >>= getArtifactSourceFiles
@@ -275,11 +275,11 @@
 getAssemblyOutput (VmImages ts _) =
     AssemblyGeneratesOutputFiles . getImageDestinationOutputFiles <$> ts
 getAssemblyOutput (CloudInit ts o) = getCloudInitOutputFiles o <$> ts
- where
-  getCloudInitOutputFiles baseName t = case t of
-      CI_ISO  -> AssemblyGeneratesOutputFiles [baseName <.> "iso"]
-      CI_VFAT -> AssemblyGeneratesOutputFiles [baseName <.> "vfat"]
-      CI_DIR  -> AssemblyCopiesSourcesToDirectory baseName
+  where
+    getCloudInitOutputFiles baseName t = case t of
+        CI_ISO  -> AssemblyGeneratesOutputFiles [baseName <.> "iso"]
+        CI_VFAT -> AssemblyGeneratesOutputFiles [baseName <.> "vfat"]
+        CI_DIR  -> AssemblyCopiesSourcesToDirectory baseName
 
 
 -- * QuickCheck instances
@@ -297,21 +297,21 @@
 
 arbitraryEachT :: Gen ([ArtifactGenerator] -> ArtifactGenerator)
 arbitraryEachT =
-    sized $
-    \n ->
-         EachT <$> vectorOf n (halfSize (listOf1 (choose ('a', 'z')))) <*>
-         oneof
-             [ listOf (vectorOf n (halfSize arbitrary))
-             , listOf1 (listOf (halfSize arbitrary))]
+    sized
+        $ \n ->
+              EachT
+                  <$> vectorOf n (halfSize (listOf1 (choose ('a', 'z'))))
+                  <*> oneof
+                          [ listOf (vectorOf n (halfSize arbitrary))
+                          , listOf1 (listOf (halfSize arbitrary))
+                          ]
 
 arbitraryEach :: Gen ([ArtifactGenerator] -> ArtifactGenerator)
-arbitraryEach =
-    sized $
-    \n ->
-         Each <$>
-         listOf
-             ((,) <$> listOf1 (choose ('a', 'z')) <*>
-              vectorOf n (halfSize (listOf1 (choose ('a', 'z')))))
+arbitraryEach = sized $ \n -> Each <$> listOf
+    ( (,) <$> listOf1 (choose ('a', 'z')) <*> vectorOf
+        n
+        (halfSize (listOf1 (choose ('a', 'z'))))
+    )
 
 
 instance Arbitrary ArtifactSource where
@@ -336,3 +336,4 @@
 
 instance Arbitrary CloudInitType where
     arbitrary = elements [CI_ISO, CI_VFAT, CI_DIR]
+
diff --git a/src/lib/B9/ArtifactGeneratorImpl.hs b/src/lib/B9/ArtifactGeneratorImpl.hs
--- a/src/lib/B9/ArtifactGeneratorImpl.hs
+++ b/src/lib/B9/ArtifactGeneratorImpl.hs
@@ -9,7 +9,7 @@
 import B9.VmBuilder
 import B9.Vm
 import B9.DiskImageBuilder
-import Data.ConfigFile.B9Extras hiding (tell)
+import System.IO.B9Extras (ensureDir, getDirectoryFiles)
 import B9.Content.StringTemplate
 import B9.Content.Generator
 import B9.Content.AST
@@ -47,15 +47,13 @@
 getArtifactOutputFiles :: ArtifactGenerator -> Either String [FilePath]
 getArtifactOutputFiles g =
   concatMap getOutputs <$> evalArtifactGenerator undefined undefined [] g
-  where
-    getOutputs  (IG _ sgs a) =
-      let
-          toOutFile (AssemblyGeneratesOutputFiles fs) = fs
-          toOutFile (AssemblyCopiesSourcesToDirectory pd) =
-            let sourceFiles = sourceGeneratorOutputFile <$> sgs
-            in (pd </>) <$> sourceFiles
-
-      in getAssemblyOutput  a >>= toOutFile
+ where
+  getOutputs (IG _ sgs a) =
+    let toOutFile (AssemblyGeneratesOutputFiles fs) = fs
+        toOutFile (AssemblyCopiesSourcesToDirectory pd) =
+          let sourceFiles = sourceGeneratorOutputFile <$> sgs
+          in  (pd </>) <$> sourceFiles
+    in  getAssemblyOutput a >>= toOutFile
 
 -- | Run an artifact generator to produce the artifacts.
 assemble :: ArtifactGenerator -> B9 [AssembledArtifact]
@@ -124,7 +122,7 @@
   in  ce { agEnv = newEnv }
 
 withXBindings :: [(String, [String])] -> CGParser () -> CGParser ()
-withXBindings bs cp = (`local`cp) `mapM_` (addBindings <$> allXBindings bs)
+withXBindings bs cp = (`local` cp) `mapM_` (addBindings <$> allXBindings bs)
  where
   allXBindings ((k, vs):rest) =
     [ (k, v) : c | v <- vs, c <- allXBindings rest ]
@@ -135,7 +133,7 @@
   -> [String]
   -> [[String]]
   -> CGParser [[(String, String)]]
-eachBindingSetT g vars valueSets = if all ((==length vars) . length) valueSets
+eachBindingSetT g vars valueSets = if all ((== length vars) . length) valueSets
   then return (zip vars <$> valueSets)
   else cgError
     ( printf
@@ -143,7 +141,7 @@
       (ppShow g)
       (ppShow vars)
       (length vars)
-      (ppShow (head (dropWhile ((==length vars) . length) valueSets)))
+      (ppShow (head (dropWhile ((== length vars) . length) valueSets)))
     )
 
 eachBindingSet
@@ -363,7 +361,7 @@
           ensureDir t
           copyFile f t
         )
-        (((instanceDir</>) &&& (ciDir</>)) <$> files)
+        (((instanceDir </>) &&& (ciDir </>)) <$> files)
       )
     infoL (printf "CREATED CI_DIR: '%s'" (takeFileName ciDir))
     return (CloudInitTarget CI_DIR ciDir)
@@ -395,7 +393,7 @@
     let vfatFile = outPath <.> "vfat"
         tmpFile  = buildDir </> takeFileName vfatFile
     ensureDir tmpFile
-    files <- map (instanceDir</>) <$> getDirectoryFiles instanceDir
+    files <- map (instanceDir </>) <$> getDirectoryFiles instanceDir
     dbgL (printf "creating cloud init vfat image '%s'" tmpFile)
     traceL (printf "adding '%s'" (show files))
     cmd (printf "truncate --size 2M '%s'" tmpFile)
@@ -409,6 +407,3 @@
     liftIO (copyFile tmpFile vfatFile)
     infoL (printf "CREATED CI_VFAT IMAGE: '%s'" (takeFileName vfatFile))
     return (CloudInitTarget CI_ISO vfatFile)
-
-
-
diff --git a/src/lib/B9/B9Config.hs b/src/lib/B9/B9Config.hs
--- a/src/lib/B9/B9Config.hs
+++ b/src/lib/B9/B9Config.hs
@@ -8,7 +8,6 @@
                    , buildDirRoot
                    , keepTempDirs
                    , execEnvType
-                   , profileFile
                    , envVars
                    , uniqueBuildDirs
                    , repositoryCache
@@ -16,6 +15,7 @@
                    , interactive
                    , libVirtLXCConfigs
                    , remoteRepos
+                   , maxLocalSharedImageRevisions
                    , B9ConfigOverride(..)
                    , noB9ConfigOverride
                    , B9ConfigAction()
@@ -35,12 +35,12 @@
                    , defaultRepositoryCache
                    , defaultB9Config
                    , openOrCreateB9Config
-                   , writeB9ConfigParser
+                   , writeB9CPDocument
                    , readB9Config
                    , parseB9Config
                    , appendPositionalArguments
-                   , modifyConfigParser
-                   , b9ConfigToConfigParser
+                   , modifyCPDocument
+                   , b9ConfigToCPDocument
                    , LogLevel(..)
                    , ExecEnvType (..)
                    , BuildVariables
@@ -56,13 +56,14 @@
 import Control.Monad.Reader
 import Control.Monad.Writer
 import System.Directory
+import System.IO.B9Extras (SystemPath(..), resolve, ensureDir)
 import qualified Data.Semigroup as Sem
 import Data.List (partition, sortBy)
 import Data.ConfigFile.B9Extras
-          ( SystemPath(..), ConfigParser, CPError, Get_C
-          , OptionSpec, resolve, ensureDir, readIniFile
-          , IniFileException(..), merge, to_string
-          , add_section, emptyCP, setshow, get)
+          ( CPDocument, CPError, CPGet
+          , CPOptionSpec, readCPDocument
+          , CPReadException(..), mergeCP, toStringCP
+          , addSectionCP, emptyCP, setShowCP, readCP )
 import B9.B9Config.LibVirtLXC as X
 import B9.B9Config.Repository as X
 import Text.Printf (printf)
@@ -79,12 +80,12 @@
                          , _buildDirRoot :: Maybe FilePath
                          , _keepTempDirs :: Bool
                          , _execEnvType :: ExecEnvType
-                         , _profileFile :: Maybe FilePath
                          , _envVars :: BuildVariables
                          , _uniqueBuildDirs :: Bool
                          , _repositoryCache :: Maybe SystemPath
                          , _repository :: Maybe String
                          , _interactive :: Bool
+                         , _maxLocalSharedImageRevisions :: Maybe Int
                          , _libVirtLXCConfigs :: Maybe LibVirtLXCConfig
                          , _remoteRepos :: [RemoteRepo]
                          } deriving (Show)
@@ -96,20 +97,20 @@
       , _buildDirRoot = getLast $ on mappend (Last . _buildDirRoot) c c'
       , _keepTempDirs = getAny $ on mappend (Any . _keepTempDirs) c c'
       , _execEnvType = LibVirtLXC
-      , _profileFile = getLast $ on mappend (Last . _profileFile) c c'
       , _envVars = on mappend _envVars c c'
       , _uniqueBuildDirs = getAll ((mappend `on` (All . _uniqueBuildDirs)) c c')
       , _repositoryCache = getLast $ on mappend (Last . _repositoryCache) c c'
       , _repository = getLast ((mappend `on` (Last . _repository)) c c')
       , _interactive = getAny ((mappend `on` (Any . _interactive)) c c')
+      , _maxLocalSharedImageRevisions = getLast ((mappend `on` (Last . _maxLocalSharedImageRevisions)) c c')
       , _libVirtLXCConfigs = getLast ((mappend `on` (Last . _libVirtLXCConfigs)) c c')
       , _remoteRepos = (mappend `on` _remoteRepos) c c'
       }
 
 instance Monoid B9Config where
   mappend = (Sem.<>)
-  mempty = B9Config Nothing Nothing Nothing False LibVirtLXC Nothing [] True
-                    Nothing Nothing False Nothing []
+  mempty = B9Config Nothing Nothing Nothing False LibVirtLXC [] True
+                    Nothing Nothing False Nothing Nothing []
 
 -- | Override b9 configuration items and/or the path of the b9 configuration file.
 -- This is useful, i.e. when dealing with command line parameters.
@@ -204,7 +205,7 @@
       (res, permanentB9ConfigUpdates) <- runWriterT
         (runReaderT (runB9ConfigAction act) runtimeCfg)
 
-      let cpExtErr = modifyConfigParser cp <$> permanentB9ConfigUpdate
+      let cpExtErr = modifyCPDocument cp <$> permanentB9ConfigUpdate
           permanentB9ConfigUpdate = if null permanentB9ConfigUpdates
             then Nothing
             else Just (mconcat permanentB9ConfigUpdates)
@@ -219,7 +220,7 @@
           (return . Just)
         )
         cpExtErr
-      mapM_ (writeB9ConfigParser (cfg ^. customB9ConfigPath)) cpExt
+      mapM_ (writeB9CPDocument (cfg ^. customB9ConfigPath)) cpExt
       return res
 -- | Run a 'B9ConfigAction' using 'noB9ConfigOverride'.
 -- See 'execB9ConfigAction' for more details.
@@ -229,45 +230,45 @@
 -- | Open the configuration file that contains the 'B9Config'.
 -- If the configuration does not exist, write a default configuration file,
 -- and create a all missing directories.
-openOrCreateB9Config :: MonadIO m => Maybe SystemPath -> m ConfigParser
+openOrCreateB9Config :: MonadIO m => Maybe SystemPath -> m CPDocument
 openOrCreateB9Config cfgPath = do
   cfgFile <- resolve (fromMaybe defaultB9ConfigFile cfgPath)
   ensureDir cfgFile
   liftIO $ do
     exists <- doesFileExist cfgFile
     if exists
-      then readIniFile (Path cfgFile)
+      then readCPDocument (Path cfgFile)
       else
-        let res = b9ConfigToConfigParser defaultB9Config
+        let res = b9ConfigToCPDocument defaultB9Config
         in  case res of
-              Left  e  -> throwIO (IniFileException cfgFile e)
-              Right cp -> writeFile cfgFile (to_string cp) >> return cp
+              Left  e  -> throwIO (CPReadException cfgFile e)
+              Right cp -> writeFile cfgFile (toStringCP cp) >> return cp
 
--- | Write the configuration in the 'ConfigParser' to either the user supplied
+-- | Write the configuration in the 'CPDocument' to either the user supplied
 -- configuration file path or to 'defaultB9ConfigFile'.
 -- Create all missing (parent) directories.
-writeB9ConfigParser :: MonadIO m => Maybe SystemPath -> ConfigParser -> m ()
-writeB9ConfigParser cfgFileIn cp = do
+writeB9CPDocument :: MonadIO m => Maybe SystemPath -> CPDocument -> m ()
+writeB9CPDocument cfgFileIn cp = do
   cfgFile <- resolve (fromMaybe defaultB9ConfigFile cfgFileIn)
   ensureDir cfgFile
-  liftIO (writeFile cfgFile (to_string cp))
+  liftIO (writeFile cfgFile (toStringCP cp))
 
 
 defaultB9Config :: B9Config
 defaultB9Config = B9Config
-  { _verbosity         = Just LogInfo
-  , _logFile           = Nothing
-  , _buildDirRoot      = Nothing
-  , _keepTempDirs      = False
-  , _execEnvType       = LibVirtLXC
-  , _profileFile       = Nothing
-  , _envVars           = []
-  , _uniqueBuildDirs   = True
-  , _repository        = Nothing
-  , _repositoryCache   = Just defaultRepositoryCache
-  , _interactive       = False
-  , _libVirtLXCConfigs = Just defaultLibVirtLXCConfig
-  , _remoteRepos       = []
+  { _verbosity                    = Just LogInfo
+  , _logFile                      = Nothing
+  , _buildDirRoot                 = Nothing
+  , _keepTempDirs                 = False
+  , _execEnvType                  = LibVirtLXC
+  , _envVars                      = []
+  , _uniqueBuildDirs              = True
+  , _repository                   = Nothing
+  , _repositoryCache              = Just defaultRepositoryCache
+  , _interactive                  = False
+  , _maxLocalSharedImageRevisions = Just 2
+  , _libVirtLXCConfigs            = Just defaultLibVirtLXCConfig
+  , _remoteRepos                  = []
   }
 
 defaultRepositoryCache :: SystemPath
@@ -284,73 +285,78 @@
 keepTempDirsK = "keep_temp_dirs"
 execEnvTypeK :: String
 execEnvTypeK = "exec_env"
-profileFileK :: String
-profileFileK = "profile_file"
 envVarsK :: String
 envVarsK = "environment_vars"
 uniqueBuildDirsK :: String
 uniqueBuildDirsK = "unique_build_dirs"
 repositoryCacheK :: String
 repositoryCacheK = "repository_cache"
+maxLocalSharedImageRevisionsK :: String
+maxLocalSharedImageRevisionsK = "max_cached_shared_images"
 repositoryK :: String
 repositoryK = "repository"
 cfgFileSection :: String
 cfgFileSection = "global"
 
--- | Parse a 'B9Config', modify it, and merge it back to the given 'ConfigParser'.
-modifyConfigParser
-  :: ConfigParser -> Endo B9Config -> Either CPError ConfigParser
-modifyConfigParser cp f = do
+-- | Parse a 'B9Config', modify it, and merge it back to the given 'CPDocument'.
+modifyCPDocument :: CPDocument -> Endo B9Config -> Either CPError CPDocument
+modifyCPDocument cp f = do
   cfg <- parseB9Config cp
-  cp2 <- b9ConfigToConfigParser (appEndo f cfg)
-  return (merge cp cp2)
+  cp2 <- b9ConfigToCPDocument (appEndo f cfg)
+  return (mergeCP cp cp2)
 
--- | Append a config file section for the 'B9Config' to an empty 'ConfigParser'.
-b9ConfigToConfigParser :: B9Config -> Either CPError ConfigParser
-b9ConfigToConfigParser c = do
-  cp1 <- add_section emptyCP cfgFileSection
-  cp2 <- setshow cp1 cfgFileSection verbosityK (_verbosity c)
-  cp3 <- setshow cp2 cfgFileSection logFileK (_logFile c)
-  cp4 <- setshow cp3 cfgFileSection buildDirRootK (_buildDirRoot c)
-  cp5 <- setshow cp4 cfgFileSection keepTempDirsK (_keepTempDirs c)
-  cp6 <- setshow cp5 cfgFileSection execEnvTypeK (_execEnvType c)
-  cp7 <- setshow cp6 cfgFileSection profileFileK (_profileFile c)
-  cp8 <- setshow cp7 cfgFileSection envVarsK (_envVars c)
-  cp9 <- setshow cp8 cfgFileSection uniqueBuildDirsK (_uniqueBuildDirs c)
-  cpA <- setshow cp9 cfgFileSection repositoryCacheK (_repositoryCache c)
+-- | Append a config file section for the 'B9Config' to an empty 'CPDocument'.
+b9ConfigToCPDocument :: B9Config -> Either CPError CPDocument
+b9ConfigToCPDocument c = do
+  cp1 <- addSectionCP emptyCP cfgFileSection
+  cp2 <- setShowCP cp1 cfgFileSection verbosityK (_verbosity c)
+  cp3 <- setShowCP cp2 cfgFileSection logFileK (_logFile c)
+  cp4 <- setShowCP cp3 cfgFileSection buildDirRootK (_buildDirRoot c)
+  cp5 <- setShowCP cp4 cfgFileSection keepTempDirsK (_keepTempDirs c)
+  cp6 <- setShowCP cp5 cfgFileSection execEnvTypeK (_execEnvType c)
+  cp7 <- setShowCP cp6 cfgFileSection envVarsK (_envVars c)
+  cp8 <- setShowCP cp7 cfgFileSection uniqueBuildDirsK (_uniqueBuildDirs c)
+  cp9 <- setShowCP cp8
+                   cfgFileSection
+                   maxLocalSharedImageRevisionsK
+                   (_maxLocalSharedImageRevisions c)
+  cpA <- setShowCP cp9 cfgFileSection repositoryCacheK (_repositoryCache c)
   cpB <-
     ( foldr (>=>)
             return
-            (libVirtLXCConfigToConfigParser <$> (_libVirtLXCConfigs c))
+            (libVirtLXCConfigToCPDocument <$> (_libVirtLXCConfigs c))
       )
       cpA
-  cpFinal <- (foldr (>=>) return (remoteRepoToConfigParser <$> _remoteRepos c))
+  cpFinal <- (foldr (>=>) return (remoteRepoToCPDocument <$> _remoteRepos c))
     cpB
-  setshow cpFinal cfgFileSection repositoryK (_repository c)
+  setShowCP cpFinal cfgFileSection repositoryK (_repository c)
 
-readB9Config :: MonadIO m => Maybe SystemPath -> m ConfigParser
-readB9Config cfgFile = readIniFile (fromMaybe defaultB9ConfigFile cfgFile)
+readB9Config :: MonadIO m => Maybe SystemPath -> m CPDocument
+readB9Config cfgFile = readCPDocument (fromMaybe defaultB9ConfigFile cfgFile)
 
-parseB9Config :: ConfigParser -> Either CPError B9Config
+parseB9Config :: CPDocument -> Either CPError B9Config
 parseB9Config cp =
-  let getr :: (Get_C a) => OptionSpec -> Either CPError a
-      getr = get cp cfgFileSection
-      getB9Config =
-        B9Config
-          <$> getr verbosityK
-          <*> getr logFileK
-          <*> getr buildDirRootK
-          <*> getr keepTempDirsK
-          <*> getr execEnvTypeK
-          <*> getr profileFileK
-          <*> getr envVarsK
-          <*> getr uniqueBuildDirsK
-          <*> getr repositoryCacheK
-          <*> getr repositoryK
-          <*> pure False
-          <*> Right (either (const Nothing) Just (parseLibVirtLXCConfig cp))
-          <*> parseRemoteRepos cp
-  in  getB9Config
+  let
+    getr :: (CPGet a) => CPOptionSpec -> Either CPError a
+    getr = readCP cp cfgFileSection
+    getB9Config =
+      B9Config
+        <$> getr verbosityK
+        <*> getr logFileK
+        <*> getr buildDirRootK
+        <*> getr keepTempDirsK
+        <*> getr execEnvTypeK
+        <*> getr envVarsK
+        <*> getr uniqueBuildDirsK
+        <*> getr repositoryCacheK
+        <*> getr repositoryK
+        <*> pure False
+        <*> pure
+              (either (const Nothing) id (getr maxLocalSharedImageRevisionsK))
+        <*> pure (either (const Nothing) Just (parseLibVirtLXCConfig cp))
+        <*> parseRemoteRepos cp
+  in
+    getB9Config
 
 
 -- | If environment variables @arg_1 .. arg_n@ are bound
diff --git a/src/lib/B9/B9Config/LibVirtLXC.hs b/src/lib/B9/B9Config/LibVirtLXC.hs
--- a/src/lib/B9/B9Config/LibVirtLXC.hs
+++ b/src/lib/B9/B9Config/LibVirtLXC.hs
@@ -1,5 +1,5 @@
 module B9.B9Config.LibVirtLXC (
-                        libVirtLXCConfigToConfigParser
+                        libVirtLXCConfigToCPDocument
                         , defaultLibVirtLXCConfig
                         , parseLibVirtLXCConfig
                      , LibVirtLXCConfig(..)
@@ -98,22 +98,22 @@
 guestRamSizeK :: String
 guestRamSizeK = "guest_ram_size"
 
-libVirtLXCConfigToConfigParser
-    :: LibVirtLXCConfig -> ConfigParser -> Either CPError ConfigParser
-libVirtLXCConfigToConfigParser c cp = do
-    cp1 <- add_section cp cfgFileSection
-    cp2 <- setshow cp1 cfgFileSection useSudoK $ useSudo c
-    cp3 <- set cp2 cfgFileSection virshPathK $ virshPath c
-    cp4 <- set cp3 cfgFileSection emulatorK $ emulator c
-    cp5 <- set cp4 cfgFileSection virshURIK $ virshURI c
-    cp6 <- setshow cp5 cfgFileSection networkIdK $ networkId c
-    cp7 <- setshow cp6 cfgFileSection guestCapabilitiesK $ guestCapabilities c
-    setshow cp7 cfgFileSection guestRamSizeK $ guestRamSize c
+libVirtLXCConfigToCPDocument
+    :: LibVirtLXCConfig -> CPDocument -> Either CPError CPDocument
+libVirtLXCConfigToCPDocument c cp = do
+    cp1 <- addSectionCP cp cfgFileSection
+    cp2 <- setShowCP cp1 cfgFileSection useSudoK $ useSudo c
+    cp3 <- setCP cp2 cfgFileSection virshPathK $ virshPath c
+    cp4 <- setCP cp3 cfgFileSection emulatorK $ emulator c
+    cp5 <- setCP cp4 cfgFileSection virshURIK $ virshURI c
+    cp6 <- setShowCP cp5 cfgFileSection networkIdK $ networkId c
+    cp7 <- setShowCP cp6 cfgFileSection guestCapabilitiesK $ guestCapabilities c
+    setShowCP cp7 cfgFileSection guestRamSizeK $ guestRamSize c
 
-parseLibVirtLXCConfig :: ConfigParser -> Either CPError LibVirtLXCConfig
+parseLibVirtLXCConfig :: CPDocument -> Either CPError LibVirtLXCConfig
 parseLibVirtLXCConfig cp =
-    let getr :: (Get_C a) => OptionSpec -> Either CPError a
-        getr = get cp cfgFileSection
+    let getr :: (CPGet a) => CPOptionSpec -> Either CPError a
+        getr = readCP cp cfgFileSection
     in  LibVirtLXCConfig
         <$> (getr useSudoK)
         <*> (getr virshPathK)
diff --git a/src/lib/B9/B9Config/Repository.hs b/src/lib/B9/B9Config/Repository.hs
--- a/src/lib/B9/B9Config/Repository.hs
+++ b/src/lib/B9/B9Config/Repository.hs
@@ -4,13 +4,13 @@
                               , SshPrivKey(..)
                               , SshRemoteHost(..)
                               , SshRemoteUser(..)
-                              , remoteRepoToConfigParser
+                              , remoteRepoToCPDocument
                               , parseRemoteRepos
                               ) where
 
 import Data.Data
 import Data.List (isSuffixOf)
-import Data.ConfigFile
+import Data.ConfigFile.B9Extras
 
 newtype RepoCache = RepoCache FilePath
   deriving (Read, Show, Typeable, Data)
@@ -36,45 +36,46 @@
 
 
 -- | Persist a repo to a configuration file.
-remoteRepoToConfigParser :: RemoteRepo
-                      -> ConfigParser
-                      -> Either CPError ConfigParser
-remoteRepoToConfigParser repo cpIn = cpWithRepo
-  where section = repoId ++ repoSectionSuffix
-        (RemoteRepo repoId
-                    remoteRootDir
-                    (SshPrivKey keyFile)
-                    (SshRemoteHost (host,port))
-                    (SshRemoteUser user)) = repo
-        cpWithRepo = do cp1 <- add_section cpIn section
-                        cp2 <- set cp1 section repoRemotePathK remoteRootDir
-                        cp3 <- set cp2 section repoRemoteSshKeyK keyFile
-                        cp4 <- set cp3 section repoRemoteSshHostK host
-                        cp5 <- setshow cp4 section repoRemoteSshPortK port
-                        set cp5 section repoRemoteSshUserK user
+remoteRepoToCPDocument :: RemoteRepo -> CPDocument -> Either CPError CPDocument
+remoteRepoToCPDocument repo cpIn = cpWithRepo
+ where
+  section = repoId ++ repoSectionSuffix
+  (RemoteRepo repoId remoteRootDir (SshPrivKey keyFile) (SshRemoteHost (host, port)) (SshRemoteUser user))
+    = repo
+  cpWithRepo = do
+    cp1 <- addSectionCP cpIn section
+    cp2 <- setCP cp1 section repoRemotePathK remoteRootDir
+    cp3 <- setCP cp2 section repoRemoteSshKeyK keyFile
+    cp4 <- setCP cp3 section repoRemoteSshHostK host
+    cp5 <- setShowCP cp4 section repoRemoteSshPortK port
+    setCP cp5 section repoRemoteSshUserK user
 
 -- | Load a repository from a configuration file that has been written by
 -- 'writeRepositoryToB9Config'.
-parseRemoteRepos :: ConfigParser -> Either CPError [RemoteRepo]
+parseRemoteRepos :: CPDocument -> Either CPError [RemoteRepo]
 parseRemoteRepos cp = traverse parseRepoSection repoSections
-  where
-    repoSections =
-          filter (repoSectionSuffix `isSuffixOf`) (sections cp)
-    parseRepoSection section = parseResult
-      where
-        getsec :: Get_C a =>  OptionSpec -> Either CPError a
-        getsec = get cp section
-        parseResult =
-          RemoteRepo repoId
-            <$> getsec repoRemotePathK
-            <*> (SshPrivKey <$> getsec repoRemoteSshKeyK)
-            <*> (SshRemoteHost <$> ((,) <$> getsec repoRemoteSshHostK
-                                        <*> getsec repoRemoteSshPortK))
-            <*> (SshRemoteUser <$> getsec repoRemoteSshUserK)
-          where
-            repoId = let prefixLen = length section - suffixLen
-                         suffixLen = length repoSectionSuffix
-                         in take prefixLen section
+ where
+  repoSections = filter (repoSectionSuffix `isSuffixOf`) (sectionsCP cp)
+  parseRepoSection section = parseResult
+   where
+    getsec :: CPGet a => CPOptionSpec -> Either CPError a
+    getsec = readCP cp section
+    parseResult =
+      RemoteRepo repoId
+        <$> getsec repoRemotePathK
+        <*> (SshPrivKey <$> getsec repoRemoteSshKeyK)
+        <*> (   SshRemoteHost
+            <$> (   (,)
+                <$> getsec repoRemoteSshHostK
+                <*> getsec repoRemoteSshPortK
+                )
+            )
+        <*> (SshRemoteUser <$> getsec repoRemoteSshUserK)
+     where
+      repoId =
+        let prefixLen = length section - suffixLen
+            suffixLen = length repoSectionSuffix
+        in  take prefixLen section
 
 repoSectionSuffix :: String
 repoSectionSuffix = "-repo"
diff --git a/src/lib/B9/B9Monad.hs b/src/lib/B9/B9Monad.hs
--- a/src/lib/B9/B9Monad.hs
+++ b/src/lib/B9/B9Monad.hs
@@ -19,7 +19,7 @@
 import Control.Monad
 import Control.Monad.IO.Class
 import Control.Monad.State
-import Control.Lens((&), (.~))
+import Control.Lens((&), (.~), (^.), (%~))
 import qualified Data.ByteString.Char8 as B
 import Data.Functor ()
 import Data.Maybe
@@ -45,64 +45,65 @@
              ,bsLogFileHandle :: Maybe SysIO.Handle
              ,bsSelectedRemoteRepo :: Maybe RemoteRepo
              ,bsRepoCache :: RepoCache
-             ,bsProf :: [ProfilingEntry]
              ,bsStartTime :: UTCTime
              ,bsInheritStdIn :: Bool}
 
-data ProfilingEntry
-  = IoActionDuration NominalDiffTime
-  | LogEvent LogLevel
-             String
-  deriving (Eq,Show)
-
-
 run :: MonadIO m => B9 a -> B9ConfigAction m a
 run action = do
   cfg <- askRuntimeConfig
   liftIO $ do
-    buildId <- generateBuildId
-    now     <- getCurrentTime
-    withBuildDir cfg buildId (withLogFile cfg . runImpl cfg buildId now)
+    buildId <- liftIO $ generateBuildId
+    now     <- liftIO $ getCurrentTime
+    liftIO
+      $ withBuildDir cfg buildId (withLogFile cfg . runImpl cfg buildId now)
  where
+  resolveBuildDirRoot cfg = case _buildDirRoot cfg of
+    Nothing    -> getCurrentDirectory >>= canonicalizePath
+    Just root' -> do
+      createDirectoryIfMissing True root'
+      canonicalizePath root'
   withLogFile cfg f = maybe
     (f Nothing)
     (\logf -> SysIO.withFile logf SysIO.AppendMode (f . Just))
     (_logFile cfg)
   withBuildDir cfg buildId =
     bracket (createBuildDir cfg buildId) (removeBuildDir cfg)
-  runImpl cfg buildId now buildDir logFileHandle =
-    bracket getCurrentDirectory setCurrentDirectory $ \_ -> do
-      traverse setCurrentDirectory (_buildDirRoot cfg)
+  runImpl cfg buildId now buildDir logFileHandle = do
       -- Check repositories
-      repoCache <- initRepoCache
-        (fromMaybe defaultRepositoryCache (_repositoryCache cfg))
-      let buildDate = formatTime undefined "%F-%T" now
-      remoteRepos' <- mapM (initRemoteRepo repoCache) (_remoteRepos cfg)
-      let
-        ctx = BuildState buildId
-                         buildDate
-                         (cfg & remoteRepos .~ remoteRepos')
-                         buildDir
-                         logFileHandle
-                         selectedRemoteRepo
-                         repoCache
-                         []
-                         now
-                         (_interactive cfg)
-        selectedRemoteRepo = do
-          sel <- _repository cfg
-          lookupRemoteRepo remoteRepos' sel <|> error
-            ( printf
-              "selected remote repo '%s' not configured, valid remote repos are: '%s'"
-              sel
-              (show remoteRepos')
-            )
-      (r, ctxOut) <- runStateT (runB9 wrappedAction) ctx
-      -- Write a profiling report
-      when (isJust (_profileFile cfg)) $ writeFile
-        (fromJust (_profileFile cfg))
-        (unlines $ show <$> reverse (bsProf ctxOut))
-      return r
+    repoCache <- initRepoCache
+      (fromMaybe defaultRepositoryCache (_repositoryCache cfg))
+    let buildDate = formatTime undefined "%F-%T" now
+    remoteRepos'    <- mapM (initRemoteRepo repoCache) (_remoteRepos cfg)
+    buildDirRootAbs <- resolveBuildDirRoot cfg
+    let finalCfg =
+          (  cfg
+          &  remoteRepos
+          .~ remoteRepos'
+          &  buildDirRoot
+          .~ Just buildDirRootAbs
+          &  envVars
+          %~ mappend [("buildDirRoot", buildDirRootAbs)]
+          )
+    let
+      ctx = BuildState buildId
+                       buildDate
+                       finalCfg
+                       buildDir
+                       logFileHandle
+                       selectedRemoteRepo
+                       repoCache
+                       now
+                       (_interactive finalCfg)
+      selectedRemoteRepo = do
+        sel <- _repository cfg
+        lookupRemoteRepo remoteRepos' sel <|> error
+          ( printf
+            "selected remote repo '%s' not configured, valid remote repos are: '%s'"
+            sel
+            (show remoteRepos')
+          )
+    (r, ctxOut) <- runStateT (runB9 wrappedAction) ctx
+    return r
   createBuildDir cfg buildId = if _uniqueBuildDirs cfg
     then do
       let subDir = "BUILD-" ++ buildId
@@ -115,18 +116,18 @@
       createDirectoryIfMissing True buildDir
       canonicalizePath buildDir
    where
-    resolveBuildDir f = case _buildDirRoot cfg of
-      Nothing    -> return f
-      Just root' -> do
-        createDirectoryIfMissing True root'
-        root <- canonicalizePath root'
-        return $ root </> f
+    resolveBuildDir f = do
+      root <- resolveBuildDirRoot cfg
+      return $ root </> f
   removeBuildDir cfg buildDir =
     when (_uniqueBuildDirs cfg && not (_keepTempDirs cfg))
       $ removeDirectoryRecursive buildDir
   generateBuildId = printf "%08X" <$> (randomIO :: IO Word32)
   -- Run the action build action
-  wrappedAction = do
+  wrappedAction   = do
+    b9cfg <- getConfig
+    traverse (traceL . printf "Root Build Directory: %s")
+             (b9cfg ^. buildDirRoot)
     startTime <- gets bsStartTime
     r         <- action
     now       <- liftIO getCurrentTime
@@ -158,22 +159,6 @@
 getRepoCache :: B9 RepoCache
 getRepoCache = gets bsRepoCache
 
--- getDownloader :: B9 Downloader
--- getDownloader = gets bsDownloader
---
--- -- | Configuration for a tool that retreives arbitrary URL and returns them to
--- -- @stdout@.
--- data Downloader =
---   Downloader {downloaderCmd :: FilePath
---              ,downloaderArgsBeforeUrl :: [String]
---              ,downloaderUrlArgPrintfFormatString :: [String]
---              ,downloaderArgsAfterUrl :: [String]}
---   deriving (Read,Show,Eq,Ord,Typeable,Generic)
---
--- readContentFromUrl :: String -> B9 B.ByteString
--- readContentFromUrl url = do
---   return expression
-
 cmd :: String -> B9 ()
 cmd str = do
   inheritStdIn <- gets bsInheritStdIn
@@ -225,14 +210,13 @@
 errorL :: String -> B9 ()
 errorL = b9Log LogError
 
-errorExitL :: String -> B9 ()
+errorExitL :: String -> B9 a
 errorExitL e = b9Log LogError e >> fail e
 
 b9Log :: LogLevel -> String -> B9 ()
 b9Log level msg = do
   lv  <- gets $ _verbosity . bsCfg
   lfh <- gets bsLogFileHandle
-  modify $ \ctx -> ctx { bsProf = LogEvent level msg : bsProf ctx }
   B9 $ liftIO $ logImpl lv lfh level msg
 
 logImpl :: Maybe LogLevel -> Maybe SysIO.Handle -> LogLevel -> String -> IO ()
@@ -262,10 +246,4 @@
   deriving (Functor,Applicative,Monad,MonadState BuildState)
 
 instance MonadIO B9 where
-  liftIO m =
-    do start <- B9 $ liftIO getCurrentTime
-       res <- B9 $ liftIO m
-       stop <- B9 $ liftIO getCurrentTime
-       let durMS = IoActionDuration (stop `diffUTCTime` start)
-       modify $ \ctx -> ctx {bsProf = durMS : bsProf ctx}
-       return res
+  liftIO m = B9 $ liftIO m
diff --git a/src/lib/B9/Content/StringTemplate.hs b/src/lib/B9/Content/StringTemplate.hs
--- a/src/lib/B9/Content/StringTemplate.hs
+++ b/src/lib/B9/Content/StringTemplate.hs
@@ -25,12 +25,10 @@
 import           Data.Text.Encoding as E
 import           Data.Text.Lazy.Encoding as LE
 import           Data.Text.Template (render,templateSafe,renderA)
+import           System.IO.B9Extras
 import           Test.QuickCheck
 import           Text.Printf
 import           Text.Show.Pretty (ppShow)
-
-import           Data.ConfigFile.B9Extras
-
 import           B9.QCUtil
 -- | A wrapper around a file path and a flag indicating if template variable
 -- expansion should be performed when reading the file contents.
diff --git a/src/lib/B9/DiskImageBuilder.hs b/src/lib/B9/DiskImageBuilder.hs
--- a/src/lib/B9/DiskImageBuilder.hs
+++ b/src/lib/B9/DiskImageBuilder.hs
@@ -22,6 +22,10 @@
                            ,pullLatestImage
                            ,) where
 
+import System.IO.Error (isDoesNotExistError)
+import System.Directory (removeFile)
+import System.IO.B9Extras (ensureDir, prettyPrintToFile, consult)
+import Control.Lens ((^.))
 import Control.Exception
 import Control.Monad
 import Control.Monad.IO.Class
@@ -29,23 +33,28 @@
 import System.FilePath
 import Text.Printf (printf)
 import Data.Maybe
-
 import Data.Function
-
 import Text.Show.Pretty (ppShow)
 import Data.List
 import Data.Data
 import Data.Generics.Schemes
 import Data.Generics.Aliases
-
 import B9.B9Monad
+import B9.B9Config
 import B9.Repository
 import B9.RepositoryIO
 import B9.DiskImages
 import qualified B9.PartitionTable as P
-import Data.ConfigFile.B9Extras
 import B9.Content.StringTemplate
 
+-- -- | Convert relative file paths of images, sources and mounted host directories
+-- -- to absolute paths relative to '_buildDirRoot'.
+-- makeImagePathsAbsoluteToBuildDirRoot :: ImageTarget -> B9 ImageTarget
+-- makeImagePathsAbsoluteToBuildDirRoot img =
+--   getConfig >>= maybe (return img) (return . go) . _buildDirRoot
+--   where
+--     go rootDir = everywhere mkAbs img
+--       where mkAbs = mkT
 
 -- | Replace $... variables inside an 'ImageTarget'
 substImageTarget :: [(String,String)] -> ImageTarget -> ImageTarget
@@ -73,8 +82,8 @@
 
     sub = subst env
 
--- | Resolve an ImageSource to an 'Image'. Note however that this source will
--- may not exist as is the case for 'EmptyImage'.
+-- | Resolve an ImageSource to an 'Image'. The ImageSource might
+-- not exist, as is the case for 'EmptyImage'.
 resolveImageSource :: ImageSource -> B9 Image
 resolveImageSource src =
   case src of
@@ -82,12 +91,14 @@
       let img = Image fsLabel imgType fsType
       in return (changeImageFormat imgType img)
     (SourceImage srcImg _part _resize) ->
-      liftIO (ensureAbsoluteImageDirExists srcImg)
+      ensureAbsoluteImageDirExists srcImg
     (CopyOnWrite backingImg) ->
-      liftIO (ensureAbsoluteImageDirExists backingImg)
-    (From name _resize) -> do
-      latestImage <- getLatestImageByName (SharedImageName name)
-      liftIO (ensureAbsoluteImageDirExists latestImage)
+      ensureAbsoluteImageDirExists backingImg
+    (From name _resize) ->
+      getLatestImageByName (SharedImageName name)
+        >>= maybe (errorExitL (printf "Nothing found for %s."
+                                      (show (SharedImageName name))))
+                  ensureAbsoluteImageDirExists
 
 -- | Return all valid image types sorted by preference.
 preferredDestImageTypes :: ImageSource -> B9 [ImageType]
@@ -103,10 +114,15 @@
         (nub [fmt, Raw, QCow2, Vmdk]
          `intersect`
          allowedImageTypesForResize resize)
-    (From name resize) -> do
-      sharedImg <- getLatestImageByName (SharedImageName name)
-      preferredDestImageTypes (SourceImage sharedImg NoPT resize)
+    (From name resize) ->
+      getLatestImageByName (SharedImageName name)
+        >>= maybe (errorExitL (printf "Nothing found for %s."
+                                       (show (SharedImageName name))))
+                  (\sharedImg ->
+                    preferredDestImageTypes (SourceImage sharedImg NoPT resize))
 
+-- | Return all supported source 'ImageType's compatible to a 'ImageDestinaion'
+-- in the preferred order.
 preferredSourceImageTypes :: ImageDestination -> [ImageType]
 preferredSourceImageTypes dest =
   case dest of
@@ -128,13 +144,24 @@
     ShrinkToMinimum -> [Raw]
     _ -> [Raw, QCow2, Vmdk]
 
-ensureAbsoluteImageDirExists :: Image -> IO Image
+-- | Create the parent directories for the file that contains the 'Image'.
+-- If the path to the image file is relative, prepend '_buildDirRoot' from
+-- the 'B9Config'.
+ensureAbsoluteImageDirExists :: Image -> B9 Image
 ensureAbsoluteImageDirExists img@(Image path _ _) = do
-  let dir = takeDirectory path
-  createDirectoryIfMissing True dir
-  dirAbs <- canonicalizePath dir
-  return $ changeImageDirectory dirAbs img
+  b9cfg <- getConfig
+  let dir =
+              let dirRel = takeDirectory path
+              in if isRelative dirRel then
+                    let prefix = fromMaybe "." (b9cfg ^. buildDirRoot)
+                    in prefix </> dirRel
+                  else dirRel
 
+  liftIO $ do
+    createDirectoryIfMissing True dir
+    dirAbs <- canonicalizePath dir
+    return $ changeImageDirectory dirAbs img
+
 -- | Create an image from an image source. The destination image must have a
 -- compatible image type and filesystem. The directory of the image MUST be
 -- present and the image file itself MUST NOT alredy exist.
@@ -149,8 +176,12 @@
     (CopyOnWrite backingImg) ->
       createCOWImage backingImg dest
     (From name resize) -> do
-      sharedImg <- getLatestImageByName (SharedImageName name)
-      materializeImageSource (SourceImage sharedImg NoPT resize) dest
+      getLatestImageByName (SharedImageName name)
+        >>= maybe (errorExitL (printf "Nothing found for %s."
+                                       (show (SharedImageName name))))
+                  (\sharedImg ->
+                        materializeImageSource
+                          (SourceImage sharedImg NoPT resize) dest)
 
 createImageFromImage :: Image -> Partition -> ImageResize -> Image -> B9 ()
 createImageFromImage src part size out = do
@@ -181,6 +212,8 @@
                  outFile
                  (imageFileExtension fmt))
 
+-- | Convert some 'Image', e.g. a temporary image used during the build phase
+-- to the final destination.
 createDestinationImage :: Image -> ImageDestination -> B9 ()
 createDestinationImage buildImg dest =
     case dest of
@@ -383,25 +416,29 @@
   return (SharedImage name (SharedImageDate date) (SharedImageBuildId buildId) imgType imgFS)
 
 -- | Convert the disk image and serialize the base image data structure.
+-- If the 'maxLocalSharedImageRevisions' configuration is set to @Just n@
+-- also delete all but the @n - 1@ newest images from the local cache.
 createSharedImageInCache :: Image -> SharedImageName -> B9 SharedImage
 createSharedImageInCache img sname@(SharedImageName name) = do
   dbgL (printf "CREATING SHARED IMAGE: '%s' '%s'" (ppShow img) name)
   sharedImg <- getSharedImageFromImageInfo sname img
   dir <- getSharedImagesCacheDir
   convertImage img (changeImageDirectory dir (sharedImageImage sharedImg))
-  tell (dir </> sharedImageFileName sharedImg) sharedImg
-  dbgL (printf "CREATED SHARED IMAGE IN CAHCE '%s'" (ppShow sharedImg))
+  prettyPrintToFile (dir </> sharedImageFileName sharedImg) sharedImg
+  dbgL (printf "CREATED SHARED IMAGE IN CACHE '%s'" (ppShow sharedImg))
+  cleanOldSharedImageRevisionsFromCache sname
   return sharedImg
 
-
 -- | Publish the latest version of a shared image identified by name to the
 -- selected repository from the cache.
 pushSharedImageLatestVersion :: SharedImageName -> B9 ()
-pushSharedImageLatestVersion name@(SharedImageName imgName) = do
-  sharedImage <- getLatestSharedImageByNameFromCache name
-  dbgL (printf "PUSHING '%s'" (ppShow sharedImage))
-  pushToSelectedRepo sharedImage
-  infoL (printf "PUSHED '%s'" imgName)
+pushSharedImageLatestVersion name@(SharedImageName imgName) =
+  getLatestSharedImageByNameFromCache name
+    >>= maybe (errorExitL (printf "Nothing found for %s." (show imgName)))
+              (\sharedImage -> do
+                    dbgL (printf "PUSHING '%s'" (ppShow sharedImage))
+                    pushToSelectedRepo sharedImage
+                    infoL (printf "PUSHED '%s'" imgName))
 
 -- | Upload a shared image from the cache to a selected remote repository
 pushToSelectedRepo :: SharedImage -> B9 ()
@@ -428,13 +465,13 @@
 
 -- | Pull the latest version of an image, either from the selected remote
 -- repo or from the repo that has the latest version.
-pullLatestImage :: SharedImageName -> B9 Bool
+pullLatestImage :: SharedImageName -> B9 (Maybe SharedImageBuildId)
 pullLatestImage name@(SharedImageName dbgName) = do
   repos <- getSelectedRepos
   let repoPredicate Cache = False
       repoPredicate (Remote repoId) = repoId `elem` repoIds
       repoIds = map remoteRepoRepoId repos
-      hasName sharedImage = name == siName sharedImage
+      hasName sharedImage = name == sharedImageName sharedImage
   candidates <- lookupSharedImages repoPredicate hasName
   let (Remote repoId, image) = last candidates
   if null candidates
@@ -442,7 +479,7 @@
       errorL
         (printf "No shared image named '%s' on these remote repositories: '%s'" dbgName
            (ppShow repoIds))
-      return False
+      return Nothing
     else do
       dbgL (printf "PULLING SHARED IMAGE: '%s'" (ppShow image))
       cacheDir <- getSharedImagesCacheDir
@@ -456,28 +493,33 @@
       pullFromRepo repo repoImgFile cachedImgFile
       pullFromRepo repo repoInfoFile cachedInfoFile
       infoL (printf "PULLED '%s' FROM '%s'" dbgName repoId)
-      return True
-
+      cleanOldSharedImageRevisionsFromCache name
+      return (Just (sharedImageBuildId image))
 
 -- | Return the 'Image' of the latest version of a shared image named 'name'
 -- from the local cache.
-getLatestImageByName :: SharedImageName -> B9 Image
+getLatestImageByName :: SharedImageName -> B9 (Maybe Image)
 getLatestImageByName name = do
   sharedImage <- getLatestSharedImageByNameFromCache name
   cacheDir <- getSharedImagesCacheDir
-  let image = changeImageDirectory cacheDir (sharedImageImage sharedImage)
-  dbgL (printf "USING SHARED SOURCE IMAGE '%s'" (show image))
+  let image = changeImageDirectory cacheDir . sharedImageImage <$> sharedImage
+  case image of
+    Just i ->
+      dbgL (printf "USING SHARED SOURCE IMAGE '%s'" (show i))
+    Nothing ->
+      errorL (printf "SOURCE IMAGE '%s' NOT FOUND" (show name))
   return image
 
 -- | Return the latest version of a shared image named 'name' from the local cache.
-getLatestSharedImageByNameFromCache :: SharedImageName -> B9 SharedImage
+getLatestSharedImageByNameFromCache :: SharedImageName -> B9 (Maybe SharedImage)
 getLatestSharedImageByNameFromCache name@(SharedImageName dbgName) = do
-  imgs <- lookupSharedImages (== Cache) ((== name) . siName)
+  imgs <- lookupSharedImages (== Cache) ((== name) . sharedImageName)
   case reverse imgs of
     (Cache, sharedImage):_rest ->
-      return sharedImage
-    _ ->
-      error (printf "No image(s) named '%s' found." dbgName)
+      return (Just sharedImage)
+    _ -> do
+      errorL (printf "No image(s) named '%s' found." dbgName)
+      return Nothing
 
 -- | Return a list of all existing sharedImages from cached repositories.
 getSharedImages :: B9 [(Repository, [SharedImage])]
@@ -530,3 +572,30 @@
 getSharedImagesCacheDir = do
   cacheDir <- localRepoDir <$> getRepoCache
   return (cacheDir </> sharedImagesRootDirectory)
+
+-- | Depending on the 'maxLocalSharedImageRevisions' 'B9Config' settings either
+-- do nothing or delete all but the configured number of most recent shared
+-- images with the given name from the local cache.
+cleanOldSharedImageRevisionsFromCache :: SharedImageName -> B9 ()
+cleanOldSharedImageRevisionsFromCache sn = do
+    b9Cfg <- getConfig
+    forM_ (b9Cfg ^. maxLocalSharedImageRevisions) $ \maxRevisions -> do
+      toDelete <- take maxRevisions <$> newestSharedImages
+      imgDir <- getSharedImagesCacheDir
+      let filesToDelete = (imgDir </>) <$> (infoFiles ++ imgFiles)
+          infoFiles     = sharedImageFileName <$> toDelete
+          imgFiles      = imageFileName . sharedImageImage <$> toDelete
+      unless (null filesToDelete) $ do
+          traceL (printf "DELETING %d OBSOLETE REVISIONS OF: %s"
+                        (length filesToDelete) (show sn))
+          mapM_ traceL filesToDelete
+          mapM_ removeIfExists filesToDelete
+   where
+    newestSharedImages :: B9 [SharedImage]
+    newestSharedImages =
+      reverse . map snd <$> lookupSharedImages (== Cache) ((sn ==) . sharedImageName)
+
+    removeIfExists fileName = liftIO $ removeFile fileName `catch` handleExists
+     where
+      handleExists e | isDoesNotExistError e = return ()
+                     | otherwise             = throwIO e
diff --git a/src/lib/B9/DiskImages.hs b/src/lib/B9/DiskImages.hs
--- a/src/lib/B9/DiskImages.hs
+++ b/src/lib/B9/DiskImages.hs
@@ -295,16 +295,16 @@
 -- * Constructors and accessors for 'SharedImage's
 
 -- | Return the name of a shared image.
-siName :: SharedImage -> SharedImageName
-siName (SharedImage n _ _ _ _) = n
+sharedImageName :: SharedImage -> SharedImageName
+sharedImageName (SharedImage n _ _ _ _) = n
 
--- | Return the date of a shared image.
-siDate :: SharedImage -> SharedImageDate
-siDate (SharedImage _ n _ _ _) = n
+-- | Return the build date of a shared image.
+sharedImageDate :: SharedImage -> SharedImageDate
+sharedImageDate (SharedImage _ n _ _ _) = n
 
 -- | Return the build id of a shared image.
-siBuildId :: SharedImage -> SharedImageBuildId
-siBuildId (SharedImage _ _ n _ _) = n
+sharedImageBuildId :: SharedImage -> SharedImageBuildId
+sharedImageBuildId (SharedImage _ _ n _ _) = n
 
 -- | Print the contents of the shared image in one line
 prettyPrintSharedImages :: [SharedImage] -> String
@@ -314,9 +314,9 @@
       where
         cols = [nameC, dateC, idC]
           where
-            nameC = col "Name" ((\(SharedImageName n) -> n) . siName)
-            dateC = col "Date" ((\(SharedImageDate n) -> n) . siDate)
-            idC = col "ID" ((\(SharedImageBuildId n) -> n) . siBuildId)
+            nameC = col "Name" ((\(SharedImageName n) -> n) . sharedImageName)
+            dateC = col "Date" ((\(SharedImageDate n) -> n) . sharedImageDate)
+            idC = col "ID" ((\(SharedImageBuildId n) -> n) . sharedImageBuildId)
             col title accessor =
               (Boxes.text title) Boxes.// (Boxes.vcat Boxes.left cells)
               where
diff --git a/src/lib/B9/LibVirtLXC.hs b/src/lib/B9/LibVirtLXC.hs
--- a/src/lib/B9/LibVirtLXC.hs
+++ b/src/lib/B9/LibVirtLXC.hs
@@ -11,15 +11,13 @@
 import Text.Printf ( printf )
 import Data.Char (toLower)
 import Control.Lens (view)
-
 import B9.ShellScript
 import B9.B9Monad
 import B9.B9Config (libVirtLXCConfigs)
 import B9.DiskImages
 import B9.ExecEnv
 import B9.B9Config.LibVirtLXC as X
-import Data.ConfigFile.B9Extras
-
+import System.IO.B9Extras (UUID(), randomUUID)
 
 logLibVirtLXCConfig :: LibVirtLXCConfig -> B9 ()
 logLibVirtLXCConfig c = traceL $ printf "USING LibVirtLXCConfig: %s" (show c)
@@ -215,5 +213,3 @@
 
 cpuCountStr :: ExecEnv -> String
 cpuCountStr = show . cpuCount . envResources
-
-
diff --git a/src/lib/B9/Repository.hs b/src/lib/B9/Repository.hs
--- a/src/lib/B9/Repository.hs
+++ b/src/lib/B9/Repository.hs
@@ -21,7 +21,7 @@
 import System.FilePath
 import System.Directory
 import B9.B9Config.Repository as X
-import Data.ConfigFile.B9Extras
+import System.IO.B9Extras
 
 -- | Initialize the local repository cache directory.
 initRepoCache :: MonadIO m => SystemPath -> m RepoCache
diff --git a/src/lib/B9/RepositoryIO.hs b/src/lib/B9/RepositoryIO.hs
--- a/src/lib/B9/RepositoryIO.hs
+++ b/src/lib/B9/RepositoryIO.hs
@@ -10,9 +10,7 @@
 
 import B9.Repository
 import B9.B9Monad
-import Data.ConfigFile.B9Extras
-
-
+import System.IO.B9Extras (ensureDir)
 import Data.List
 import Control.Monad.IO.Class
 import System.Directory
diff --git a/src/lib/B9/VmBuilder.hs b/src/lib/B9/VmBuilder.hs
--- a/src/lib/B9/VmBuilder.hs
+++ b/src/lib/B9/VmBuilder.hs
@@ -58,7 +58,7 @@
       srcImg <- resolveImageSource imageSource
       let buildImg = changeImageFormat buildImgType
                                        (changeImageDirectory buildDir srcImg)
-      buildImgAbsolutePath <- liftIO (ensureAbsoluteImageDirExists buildImg)
+      buildImgAbsolutePath <- ensureAbsoluteImageDirExists buildImg
       materializeImageSource imageSource buildImg
       return buildImgAbsolutePath
 
diff --git a/src/lib/Data/ConfigFile/B9Extras.hs b/src/lib/Data/ConfigFile/B9Extras.hs
--- a/src/lib/Data/ConfigFile/B9Extras.hs
+++ b/src/lib/Data/ConfigFile/B9Extras.hs
@@ -1,151 +1,91 @@
-{-# Language DeriveDataTypeable #-}
+{-# Language DeriveDataTypeable, ConstraintKinds #-}
 {-| Extensions to 'Data.ConfigFile' and utility functions for dealing with
     configuration in general and reading/writing files. -}
-module Data.ConfigFile.B9Extras ( allOn
-                                , lastOn
-                                , SystemPath (..)
-                                , resolve
-                                , ensureDir
-                                , readIniFile
-                                , getOptionM
-                                , getOption
-                                , getOptionOr
-                                , IniFileException(..)
-                                , module Data.ConfigFile
-                                , UUID (..)
-                                , randomUUID
-                                , tell
-                                , consult
-                                , getDirectoryFiles
-                                , maybeConsult
-                                , maybeConsultSystemPath
+module Data.ConfigFile.B9Extras ( addSectionCP
+                                , setShowCP
+                                , setCP
+                                , readCP
+                                , mergeCP
+                                , toStringCP
+                                , sectionsCP
+                                , emptyCP
+                                , type CPGet
+                                , type CPOptionSpec
+                                , type CPSectionSpec
+                                , type CPDocument
+                                , CPError()
+                                , readCPDocument
+                                , CPReadException(..)
                                 ) where
 
+#if !MIN_VERSION_base(4,10,0)
 import Data.Monoid
-import Data.Function ( on )
+#endif
 import Data.Typeable
 #if !MIN_VERSION_base(4,8,0)
 import Control.Applicative
 #endif
-import Control.Exception
-import Control.Monad.IO.Class
-import System.Directory
-import Text.Read ( readEither )
-import System.Random ( randomIO )
-import Data.Word ( Word16, Word32 )
-import System.FilePath
-import Text.Printf
 import Data.ConfigFile
-import Data.Data
-import Text.Show.Pretty (ppShow)
+import Control.Exception
+import Control.Monad.Except
+import System.IO.B9Extras
 
-allOn :: (a -> Maybe Bool) -> a -> a -> Maybe Bool
-allOn getter x y = getAll <$> on mappend (fmap All . getter) x y
+-- * Aliases for functions and types from 'ConfigParser' in 'Data.ConfigFile'
 
-lastOn :: (a -> Maybe b) -> a -> a -> Maybe b
-lastOn getter x y = getLast $ on mappend (Last . getter) x y
+-- | An alias for  'ConfigParser'
+type CPDocument = ConfigParser
 
-data SystemPath = Path FilePath
-                | InHomeDir FilePath
-                | InB9UserDir FilePath
-                | InTempDir FilePath
-  deriving (Eq, Read, Show, Typeable, Data)
+-- | An alias for 'SectionSpec'.
+type CPSectionSpec = SectionSpec
 
-resolve :: MonadIO m => SystemPath -> m FilePath
-resolve (Path p) = return p
-resolve (InHomeDir p) = liftIO $ do
-  d <- getHomeDirectory
-  return $ d </> p
-resolve (InB9UserDir p) = liftIO $ do
-  d <- getAppUserDataDirectory "b9"
-  return $ d </> p
-resolve (InTempDir p) = liftIO $ do
-  d <- getTemporaryDirectory
-  return $ d </> p
+-- | An alias for 'OptionSpec'
+type CPOptionSpec = OptionSpec
 
--- | Get all files from 'dir' that is get ONLY files not directories
-getDirectoryFiles :: MonadIO m => FilePath -> m [FilePath]
-getDirectoryFiles dir = do
-  entries <- liftIO (getDirectoryContents dir)
-  fileEntries <- mapM (liftIO . doesFileExist . (dir </>)) entries
-  return (snd <$> filter fst (fileEntries `zip` entries))
+-- | An alias for 'setshow'.
+setShowCP :: (Show a, MonadError CPError m) => CPDocument -> CPSectionSpec -> CPOptionSpec -> a -> m CPDocument
+setShowCP = setshow
 
-ensureDir :: MonadIO m => FilePath -> m ()
-ensureDir p = liftIO (createDirectoryIfMissing True $ takeDirectory p)
+-- | An alias for 'set'.
+setCP :: (MonadError CPError m) => CPDocument -> CPSectionSpec -> CPOptionSpec -> String -> m CPDocument
+setCP = set
 
-data ReaderException = ReaderException FilePath String
-  deriving (Show, Typeable)
-instance Exception ReaderException
+-- | An alias for 'get'.
+readCP :: (CPGet a, MonadError CPError m) => CPDocument -> CPSectionSpec -> CPOptionSpec -> m a
+readCP = get
 
-tell :: (MonadIO m, Show a) => FilePath -> a -> m ()
-tell f x = do
-  ensureDir f
-  liftIO (writeFile f (ppShow x))
+-- | An alias for 'Get_C'
+type CPGet a = Get_C a
 
-consult :: (MonadIO m, Read a) => FilePath -> m a
-consult f = liftIO $ do
-  c <- readFile f
-  case readEither c of
-    Left e ->
-      throwIO $ ReaderException f e
-    Right a ->
-      return a
+-- | An alias for 'add_section'.
+addSectionCP :: MonadError CPError m => CPDocument -> CPSectionSpec -> m CPDocument
+addSectionCP = add_section
 
-maybeConsult :: (MonadIO m, Read a) => Maybe FilePath -> a -> m a
-maybeConsult Nothing defaultArg = return defaultArg
-maybeConsult (Just f) defaultArg = liftIO $ do
-  exists <- doesFileExist f
-  if exists
-    then consult f
-    else return defaultArg
+-- | An alias for 'merge'.
+mergeCP :: CPDocument -> CPDocument -> CPDocument
+mergeCP = merge
 
-maybeConsultSystemPath :: (MonadIO m, Read a) => Maybe SystemPath -> a -> m a
-maybeConsultSystemPath Nothing defaultArg = return defaultArg
-maybeConsultSystemPath (Just f) defaultArg = liftIO $ do
-  f' <- resolve f
-  exists <- doesFileExist f'
-  if exists
-    then consult f'
-    else return defaultArg
+-- | An alias for 'to_string'
+toStringCP :: CPDocument -> String
+toStringCP = to_string
 
-data IniFileException = IniFileException FilePath CPError
-                      deriving (Show, Typeable)
-instance Exception IniFileException
+-- | An alias for 'sections'.
+sectionsCP :: CPDocument -> [SectionSpec]
+sectionsCP = sections
 
-readIniFile :: MonadIO m => SystemPath -> m ConfigParser
-readIniFile cfgFile' = do
+-- * Reading a 'CPDocument' from a 'SystemPath'
+
+-- | Read a file and try to parse the contents as a 'CPDocument', if something
+-- goes wrong throw a 'CPReadException'
+readCPDocument :: MonadIO m => SystemPath -> m CPDocument
+readCPDocument cfgFile' = do
   cfgFilePath <- resolve cfgFile'
   liftIO $ do
     res <- readfile emptyCP cfgFilePath
     case res of
-      Left e -> throwIO (IniFileException cfgFilePath e)
+      Left e -> throwIO (CPReadException cfgFilePath e)
       Right cp -> return cp
 
-getOption :: (Get_C a, Monoid a) => ConfigParser -> SectionSpec -> OptionSpec -> a
-getOption cp sec key = either (const mempty) id $ get cp sec key
-
-getOptionM :: (Read a) => ConfigParser -> SectionSpec -> OptionSpec -> Maybe a
-getOptionM cp sec key = either (const Nothing) id $ get cp sec key
-
-getOptionOr :: (Get_C a) => ConfigParser -> SectionSpec -> OptionSpec -> a -> a
-getOptionOr cp sec key dv = either (const dv) id $ get cp sec key
-
-newtype UUID = UUID (Word32, Word16, Word16, Word16, Word32, Word16)
-             deriving (Read, Show, Eq, Ord)
-
-instance PrintfArg UUID where
-  formatArg (UUID (a, b, c, d, e, f)) fmt
-    | fmtChar (vFmt 'U' fmt) == 'U' =
-        let str = (printf "%08x-%04x-%04x-%04x-%08x%04x" a b c d e f :: String)
-        in formatString str (fmt { fmtChar = 's', fmtPrecision = Nothing })
-    | otherwise = errorBadFormat $ fmtChar fmt
-
-
-randomUUID :: MonadIO m => m UUID
-randomUUID = liftIO
-               (UUID <$> ((,,,,,) <$> randomIO
-                                  <*> randomIO
-                                  <*> randomIO
-                                  <*> randomIO
-                                  <*> randomIO
-                                  <*> randomIO))
+-- | An exception thrown by 'readCPDocument'.
+data CPReadException = CPReadException FilePath CPError
+                      deriving (Show, Typeable)
+instance Exception CPReadException
diff --git a/src/lib/System/IO/B9Extras.hs b/src/lib/System/IO/B9Extras.hs
new file mode 100644
--- /dev/null
+++ b/src/lib/System/IO/B9Extras.hs
@@ -0,0 +1,118 @@
+-- | Some utilities to deal with IO in B9.
+module System.IO.B9Extras (SystemPath (..)
+                                , resolve
+                                , ensureDir
+                                , getDirectoryFiles
+                                , prettyPrintToFile
+                                , consult
+                                , ConsultException(..)
+                                , randomUUID
+                                 , UUID()
+                                ) where
+
+import Data.Typeable
+#if !MIN_VERSION_base(4,8,0)
+import Control.Applicative
+#endif
+import Control.Exception
+import Control.Monad.Except
+import System.Directory
+import Text.Read ( readEither )
+import System.Random ( randomIO )
+import Data.Word ( Word16, Word32 )
+import System.FilePath
+import Text.Printf
+import Data.Data
+import Text.Show.Pretty (ppShow)
+
+-- * Relative Paths
+
+-- | A data type encapsulating different kinds of relative or absolute paths.
+data SystemPath = Path FilePath  -- ^ A path that will just be passed through
+                | InHomeDir FilePath -- ^ A OS specific path relative to
+                                      -- the home directory of a user.
+                | InB9UserDir FilePath -- ^ A path relative to the @b9@ sub of
+                                       -- the users application configuration
+                                       -- directory 'getAppUserDataDirectory'
+                | InTempDir FilePath -- ^ A path relative to the systems
+                                     -- temporary directory.
+  deriving (Eq, Read, Show, Typeable, Data)
+
+-- | Convert a 'SystemPath' to a 'FilePath'.
+resolve :: MonadIO m => SystemPath -> m FilePath
+resolve (Path p) = return p
+resolve (InHomeDir p) = liftIO $ do
+  d <- getHomeDirectory
+  return $ d </> p
+resolve (InB9UserDir p) = liftIO $ do
+  d <- getAppUserDataDirectory "b9"
+  return $ d </> p
+resolve (InTempDir p) = liftIO $ do
+  d <- getTemporaryDirectory
+  return $ d </> p
+
+-- * File System Directory Utilities
+
+-- | Get all files from 'dir' that is get ONLY files not directories
+getDirectoryFiles :: MonadIO m => FilePath -> m [FilePath]
+getDirectoryFiles dir = do
+  entries <- liftIO (getDirectoryContents dir)
+  fileEntries <- mapM (liftIO . doesFileExist . (dir </>)) entries
+  return (snd <$> filter fst (fileEntries `zip` entries))
+
+-- | Create all missing parent directories of a file path.
+-- Note that the file path is assumed to be of a regular file, and
+-- 'takeDirectory' is applied before creating the directory.
+ensureDir :: MonadIO m => FilePath -> m ()
+ensureDir p = liftIO (createDirectoryIfMissing True $ takeDirectory p)
+
+-- * Reading and Writing from/to Files
+
+-- | Write a value of a type that is an instance of 'Show' to file.
+-- This function uses 'ppShow' instead of the given 'Show' instance.
+prettyPrintToFile :: (MonadIO m, Show a) => FilePath -> a -> m ()
+prettyPrintToFile f x = do
+  ensureDir f
+  liftIO (writeFile f (ppShow x))
+
+-- | Read a value of a type that is an instance of 'Read' from a file.
+-- This function throws a 'ConsultException' when the read the file failed.
+consult :: (MonadIO m, Read a) => FilePath -> m a
+consult f = liftIO $ do
+  c <- readFile f
+  case readEither c of
+    Left e ->
+      throwIO $ ConsultException f e
+    Right a ->
+      return a
+
+-- | An 'Exception' thrown by 'consult' to indicate the file does not
+-- contain a 'read'able String
+data ConsultException = ConsultException FilePath String
+  deriving (Show, Typeable)
+
+instance Exception ConsultException
+
+-- * Unique Random IDs
+
+-- | A bunch of numbers, enough to make globally unique IDs. Create one of these
+-- using 'randomUUID'.
+newtype UUID = UUID (Word32, Word16, Word16, Word16, Word32, Word16)
+             deriving (Read, Show, Eq, Ord)
+
+instance PrintfArg UUID where
+  formatArg (UUID (a, b, c, d, e, f)) fmt
+    | fmtChar (vFmt 'U' fmt) == 'U' =
+        let str = (printf "%08x-%04x-%04x-%04x-%08x%04x" a b c d e f :: String)
+        in formatString str (fmt { fmtChar = 's', fmtPrecision = Nothing })
+    | otherwise = errorBadFormat $ fmtChar fmt
+
+-- | Generate a random 'UUID'.
+randomUUID :: MonadIO m => m UUID
+randomUUID = liftIO
+               (UUID <$> ((,,,,,) <$> randomIO
+                                  <*> randomIO
+                                  <*> randomIO
+                                  <*> randomIO
+                                  <*> randomIO
+                                  <*> randomIO))