1.上锁
[root@cs70-moban etc]# useradd wangli
[root@cs70-moban etc]# chattr +i /etc/passwd /etc/shadow /etc/group /etc/gshadow /etc/inittab
[root@cs70-moban etc]# useradd sumin
useradd: cannot open /etc/passwd
2.查看对那些文件做了什么操作
[root@cs70-moban etc]# lsattr /etc/passwd /etc/shadow /etc/group /etc/gshadow /etc/inittab
----i----------- /etc/passwd
----i----------- /etc/shadow
----i----------- /etc/group
----i----------- /etc/gshadow
----i----------- /etc/inittab
这里做了+i操作
3.解锁
[root@cs70-moban etc]# chattr -i /etc/passwd /etc/shadow /etc/group /etc/gshadow /etc/inittab
[root@cs70-moban etc]# useradd sumin
[root@cs70-moban etc]# lsattr /etc/passwd /etc/shadow /etc/group /etc/gshadow /
etc/inittab
---------------- /etc/passwd
---------------- /etc/shadow
---------------- /etc/group
---------------- /etc/gshadow
---------------- /etc/inittab