--- File.chmod(mode[, filename[, ...]])
--- File.lchmod(mode[, filename[, ...]])             ruby 1.7 feature

    եΥ⡼ɤ mode ѹޤ⡼ɤѹե
    ο֤ޤ⡼ɤѹ˼Ԥ㳰 
    Errno::EXXX ȯޤ

    mode  chmod(2) [manual page] Ʊͤ˿ͤǻꤷޤ

    lchmod ϡܥå󥯤˴ؤƥ󥯤ΤΤ
    ⡼ɤѹޤlchmod(2) [manual page] 
    ƤʤƥǤΥ᥽åɤƤӽФ 
    NotImplementedError 㳰ȯޤ

