def relative_path(path)
      path = File.expand_path(path)
      root = full_path("")
      if path.size >= root.size && path[0...root.size] == root
        path[0...root.size] = ""
        path = "/" if path.size == 0
        path
      end
    end
def relative_path(path)
      path = File.expand_path(path)
      root = full_path("")
      if path.size >= root.size && path[0...root.size] == root
        path[0...root.size] = ""
        path = "/" if path.size == 0
        path
      end
    end
Returns a path relative to the base path, given the full path. This is the inverse of
 full_path.