1．修改MySQL的登录设置

vi /etc/my.cnf

在[mysqld]的段中加上一句：skip-grant-tables

例如：

[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
skip-grant-tables

保存并且退出vi。

2．重新启动mysqld

/etc/init.d/mysqld restart

Stopping MySQL: [ OK ]
Starting MySQL: [ OK ]

3．登录并修改MySQL的root密码

/usr/bin/mysql

Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3 to server version: 3.23.56
Type ‘help;’ or ‘\h’ for help. Type ‘\c’ to clear the buffer.
mysql> use mysql ;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> UPDATE user SET Password = password ('new-password') WHERE User = 'root' ;
Query OK, 0 rows affected (0.00 sec)
Rows matched: 2 Changed: 0 Warnings: 0
mysql> flush privileges ;
Query OK, 0 rows affected (0.01 sec)
mysql> quit
Bye

4．将MySQL的登录设置修改回来

vi /etc/my.cnf

将刚才在[mysqld]的段中加上的skip-grant-tables删除
保存并且退出vi。

5．重新启动mysqld

/etc/init.d/mysqld restart

Stopping MySQL: [ OK ]
Starting MySQL: [ OK ]