在其他用户下，报错，于是在root用户下进行修改权限
chmod 777 /看一下：
total 98
dr-xr-xr-x. 2 root root 4096 May 1 08:07 bin
dr-xr-xr-x. 5 root root 1024 May 1 05:31 boot
drwxr-xr-x. 19 root root 3800 May 1 05:46 dev
drwxr-xr-x. 116 root root 12288 May 1 08:13 etc
drwxr-xr-x. 4 root root 4096 May 1 08:09 home
dr-xr-xr-x. 13 root root 4096 May 1 08:07 lib
dr-xr-xr-x. 9 root root 12288 May 1 08:07 lib64
drwx------. 2 root root 16384 May 1 05:02 lost+found
drwxr-xr-x. 2 root root 4096 Sep 23 2011 media
drwxr-xr-x. 2 root root 0 May 1 05:46 misc
drwxr-xr-x. 2 root root 4096 Sep 23 2011 mnt
drwxr-xr-x. 2 root root 0 May 1 05:46 net
drwxr-x---. 17 root root 4096 May 1 08:14 opt
dr-xr-xr-x. 158 root root 0 May 1 05:45 proc
dr-xr-x---. 28 root root 4096 May 1 08:18 root
dr-xr-xr-x. 2 root root 12288 May 1 08:07 sbin
drwxr-xr-x. 7 root root 0 May 1 05:45 selinux
drwxr-xr-x. 2 root root 4096 Sep 23 2011 srv
drwxr-xr-x. 13 root root 0 May 1 05:45 sys
drwxrwxrwt. 14 root root 4096 May 1 08:07 tmp
drwxr-xr-x. 13 root root 4096 May 1 05:03 usr
drwxr-xr-x. 22 root root 4096 May 1 05:24 var发现根本没有起作用
看来是没法chmod /
还是直接修改/opt路径下
chmod 777 /opt/看一下效果：
total 98
dr-xr-xr-x. 2 root root 4096 May 1 08:07 bin
dr-xr-xr-x. 5 root root 1024 May 1 05:31 boot
drwxr-xr-x. 19 root root 3800 May 1 05:46 dev
drwxr-xr-x. 116 root root 12288 May 1 08:13 etc
drwxr-xr-x. 4 root root 4096 May 1 08:09 home
dr-xr-xr-x. 13 root root 4096 May 1 08:07 lib
dr-xr-xr-x. 9 root root 12288 May 1 08:07 lib64
drwx------. 2 root root 16384 May 1 05:02 lost+found
drwxr-xr-x. 2 root root 4096 Sep 23 2011 media
drwxr-xr-x. 2 root root 0 May 1 05:46 misc
drwxr-xr-x. 2 root root 4096 Sep 23 2011 mnt
drwxr-xr-x. 2 root root 0 May 1 05:46 net
drwxrwxrwx. 17 root root 4096 May 1 08:14 opt
dr-xr-xr-x. 158 root root 0 May 1 05:45 proc
dr-xr-x---. 28 root root 4096 May 1 08:18 root
dr-xr-xr-x. 2 root root 12288 May 1 08:07 sbin
drwxr-xr-x. 7 root root 0 May 1 05:45 selinux
drwxr-xr-x. 2 root root 4096 Sep 23 2011 srv
drwxr-xr-x. 13 root root 0 May 1 05:45 sys
drwxrwxrwt. 14 root root 4096 May 1 08:07 tmp
drwxr-xr-x. 13 root root 4096 May 1 05:03 usr
drwxr-xr-x. 22 root root 4096 May 1 05:24 var看来已经起了作用了
小结：看来对根目录是没法修改权限的