visudo
用户 机器=（极权那个角色的权利）
root ALL=(ALL) ALL
stephen ALL=(ALL) /usr/sbin/useradd,/usr/sbin/userdel
[stephen@52game ~]$ sudo /usr/sbin/useradd kkk
[sudo] password for stephen:
Sorry, try again.
[sudo] password for stephen:
[stephen@52game ~]$ id kkk
uid=501(kkk) gid=501(kkk) 组=501(kkk)
[stephen@52game ~]$ sudo /usr/sbin/useradd 380233718
[stephen@52game ~]$ id 380233718
uid=502(380233718) gid=502(380233718) 组=502(380233718)
[stephen@52game ~]$
注意：sudo是钦差大臣，不能少，不能修改修改rooot。
皇帝的太子
leader ALL=(ALL) ALL
[root@52game ~]# useradd leader
[root@52game ~]# passwd leader
不用告诉leader root密码，可以切换到root
[root@52game ~]# su - leader
[leader@52game ~]$ su -
密码：
[leader@52game ~]$ sudo su -
We trust you have received the usual lecture from the local System
Administrator. It usually boils down to these three things:
#1) Respect the privacy of others.
#2) Think before you type.
#3) With great power comes great responsibility.
[sudo] password for leader:
[root@52game ~]#
查询自己权限
sudo -l
管理员用户切换不需要密码
stephen ALL=(ALL) NOPASSWD:ALL
[root@52game ~]# su - stephen
[stephen@52game ~]$ su -
密码：
[stephen@52game ~]$ sudo su -
[root@52game ~]#
立即使环境变量生效
. .bash_profile
source .bash_profile
