1.查看初始化密码：
[root@lone-centos67 ~]# grep 'temporary password' /var/log/mysqld.log
2016-10-13T06:30:03.521325Z 1 [Note] A temporary password is generated for root@localhost: E<apj1+mshge
<apj1+mshge

初始化密码为：E<apj1+mshge
密码是随机产生的

</apj1+mshge
2.登录及修改密码
[root@lone-centos67 ~]# mysql -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 9
Server version: 5.7.15 MySQL Community Server (GPL)


Copyright (c) 2000, 2016, 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.


mysql>

mysql> show databases;

修改密码
mysql> alter user root@localhost identified by 'xxx';
新密码要求，必须包含大小写字母数字及符号。

关闭密码复杂度验证：
在my.cnf添加validate_password=off
</apj1+mshge
</apj1+mshge