第一步：(停掉正在运行的mysql)

[root@maomao ~]# /etc/init.d/mysqld
stop

Stopping
MySQL:                                           
[  OK  ]

 

第二步：使用 “--skip-grant-tables”参数重新启动mysql

[root@mcy400 ~]# cd 到mysql目录，这里到bin目录，会提示“Please do a cd to the mysql installation directory and restart”
[root@mcy400 ~]# ./bin/mysqld_safe
--skip-grant-tables

[root@cy400 ~]# Starting mysqld daemon with
databases from /var/lib/mysql

注意：如果停在这一步的时候，请克隆一个新的会话接着下一步操作

 

第三步：用帐号登录mysql

[root@cy400 ~]# mysql -u root

Welcome to the MySQL monitor.  Commands end with ;
or \g.

Your MySQL connection id is 1

Server version: 5.0.77 Source distribution

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

 

第四步：改变用户数据库

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

 

第五步：修改密码，下面()内的root123为新密码
mysql>
update user set password=password('root123') where
user='root';

 

第六步：刷新权限表

mysql> flush privileges;

ERROR 1064 (42000): You have an error in your SQL syntax; check the
manual that corresponds to your MySQL server version for the right
syntax to use near 'previleges' at line 1

 

第七步：退出mysql
mysql> quit

Bye

 

第八步：对mysql进行重启
[root@cy400 ~]# /etc/init.d/mysqld
restart;

Stopping
MySQL:                                           
[  OK  ]

Starting
MySQL:                                           
[  OK  ]

 

第九步：用更改过的密码重新登录即可。
[root@cy400 ~]# mysql -u root -p

Enter password: admin123

Welcome to the MySQL monitor.  Commands end with ;
or \g.

Your MySQL connection id is 2

Server version: 5.0.77 Source distribution

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql> quit

Bye

[root@cy400 ~]#

加入如下自动启动命令 /etc/rc.d/init.d/mysqld start

转载：http://blog.sina.com.cn/s/blog_4488002e0100z574.html

参考：http://blog.chinaunix.net/uid-25266990-id-2921603.html