userdel -r 和userdel的区别:
userdel删除用户不删除家目录;userdel -r 删除家目录并删除用户
[root@localhost ~]# useradd jin
[root@localhost ~]# userdel jin
[root@localhost ~]# grep bash /etc/passwd
root:x:0:0:root:/root:/bin/bash
[root@localhost ~]# ls /home/
jin
[root@localhost ~]# useradd jin1
[root@localhost ~]# userdel -r jin1
[root@localhost ~]# ls /home/
jin
创建系统用户并不可登录
[root@localhost ~]# useradd -s /sbin/nologin -M nginx1
[root@localhost ~]# grep nginx1 /etc/passwd
nginx1:x:1000:1000::/home/nginx1:/sbin/nologin