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初始化密码为：E密码是随机产生的
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

文章标题：MySQL5.7初始密码查看及重置-创新互联
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