--- FileUtils.rm_r( list, *options )
  Options: force noop verbose

  եޤϥǥ쥯ȥ list[0], list[1] Ĥõޤ
  force ץϤ StandardError ̵뤷ޤ

    FileUtils.rm_r Dir.glob('/tmp/*')
    FileUtils.rm_r '/', :force          #  :-)

