有时候有人想偷懒，直接免密登录mysql。可以按照以下方法操作

1.编辑配置文件

vim /root/.my.cnf
[client]
user=root
password=123

2.修改权限

chmod 400 ~/.my.cnf

3.登录查看

[root@localhost ~]# mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 15
Server version: 5.7.20-log MySQL Community Server (GPL)
Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.root@localhost :(none)12:09:35>

可以了，现在能免密登录了！