# File src/ruby_supportlib/phusion_passenger/abstract_installer.rb, line 460
    def list_parent_directories(dir)
      dirs = []
      components = File.expand_path(dir).split(File::SEPARATOR)
      components.shift # Remove leading /
      components.size.times do |i|
        dirs << File::SEPARATOR + components[0 .. i].join(File::SEPARATOR)
      end
      return dirs.reverse
    end