     @command = "help" if not @command or @command is "-h" or @command is "--help"
     fn = @commands[@command]
 
-    throw new Error "Invalid argument" if typeof fn isnt "function"
+    throw new Error "Unknown method #{@command}" if typeof fn isnt "function"
 
     @config = @loadConfig "./decking.json" if @command isnt "help"
 

          # was a group wide key maybe?
          container[key] = value

    maxNameLength = container.name.length if container.name.length > maxNameLength

  # resolve dependency order

  # merge group overrides if present
  for _, container of containerDetails
    container.originalName = container.name

    if groupName
      container.group = groupName
      container.name += ".#{groupName}"
