就像在windows下创建两个点以上的文件无法删除一样，linux下也可以有同样的技巧：
[root@localhost ~]# touch test/.immutable [root@localhost ~]# chattr +i test/.immutable [root@localhost ~]# chattr +i test/ [root@localhost ~]# mkdir test/foobar mkdir: cannot create directory `test/foobar': Permission denied [root@localhost ~]# touch test/barfoo touch: cannot touch `test/barfoo': Permission denied