????1??????????????????
????chgrp(change group):???????????飻
????chgrp [-R] dirname/filename;
????-R:???г????????????????????μ??????

????chown(change owner):?????????
????chown [-R] ?????[??????]dirname/filename;
????-R:???г????????????????????μ??????
????[??????]:????????????????????????

????chmod(change mode):??????

????r:4 w:2 x:1
????u:?????? g:????? o:???? a:??????
???????????????????????????
????2??ls????????
????-a???г????????????????????
????-d?????г??????
????-l:?г????????????
????-s?????????С?????г?
????-t????????????г?
????--full-time????????????????
????--time=(atime??ctime)?????????????