Linux普通用户切换省略输入用户名密码

今天没事，做了个小实验，普通用户切换如何省略密码
1、省略密码验证

很简单，只需把/etc/passwd中的root:x:0:0:root:/root:/bin/bash，改为root::0:0:root:/root:/bin/bash，就可以了，就是去掉了里面的x，这样root用户就不用密码了。其他用户也一样。
[root@localhost ~]# useradd   user01
[root@localhost ~]# passwd   user01
Changing password for user user01.
New UNIX password:
BAD PASSWORD: it is based on a dictionary word
Retype new UNIX password:
passwd: all authentication tokens updated successfully.
[root@localhost ~]# useradd   user02
[root@localhost ~]# passwd  user02
Changing password for user user02.
New UNIX password:
BAD PASSWORD: it is based on a dictionary word
Retype new UNIX password:
passwd: all authentication tokens updated successfully.
创建完用户名密码后，现在切换下用户
[root@localhost ~]# su - user01
[user01@localhost ~]$ whoami
user01
[user01@localhost ~]$ su - user02
口令：
[user02@localhost ~]$
输入用户口令后，才能切换
[user02@localhost ~]$ su -
口令：
[root@localhost ~]#
[root@localhost ~]# vim /etc/passwd
将x去掉
user01:x:502:502::/home/user01:/bin/bash
user02:x:503:503::/home/user02:/bin/bash
修改为如下格式
user01::502:502::/home/user01:/bin/bash
user02::503:503::/home/user02:/bin/bash
保存后再进行切换实验，
[root@localhost ~]# su - user01
[user01@localhost ~]$ whoami
user01
[user01@localhost ~]$ su - user02
[user02@localhost ~]$ whoami
user02
[user02@localhost ~]$
现在可以实现无密码切换用户