1.、确保 mysql server 已经停止运行
查询mysql server 是否处于运行状态： /usr/local/mysql/support-files/mysql.server status
2、如果正在运行，则将其停止： /usr/local/mysql/support-files/mysql.server stop
3、以 skip-grant-tables 模式启动mysql： /usr/local/mysql/support-files/mysql.server start --skip-grant-tables
4、 修改密码
登录 mysql
mysql -u root
设置密码为空
mysql> UPDATE mysql.user SET authentication_string=null WHERE User='root';
mysql> flush privileges;
mysql> exit;
5、再次登录 mysql
mysql -u root
更改密码
mysql> ALTER USER 'root'@'%' IDENTIFIED WITH mysql_native_password BY '123';
mysql> flush privileges;
mysql> exit;
6、以正常模式启动 mysql
sudo /usr/local/mysql/support-files/mysql.server stop
sudo /usr/local/mysql/support-files/mysql.server start