http://www.cnblogs.com/yuxc/archive/2012/07/25/2607587.html
1、结束当前正在运行的mysql进程。
# /etc/init.d/mysql stop
2、用mysql安全模式运行并跳过权限验证。
# /usr/bin/mysqld_safe --skip-grant-tables
3、重开一个终端以root身份登录mysql。
# mysql -u root
4、修改root用户口令。
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(‘root‘) where User =‘root‘;
Query OK, 3 rows affected (0.00 sec)
Rows matched: 3 Changed: 3 Warnings: 0
mysql> exit
5、结束mysql安全模式，用正常模式运行mysql。
# /etc/init.d/mysql restart
6、试试你新修改的口令
mysql> show grants for ‘root‘@‘127.0.0.1‘;
mysql> flush privileges；
mysql> quit
1 mysql> use mysql 2 Reading table information for completion of table and column names 3 You can turn off this feature to get a quicker startup with -A 4 5 Database changed 6 mysql> update user set Password = PASSWORD(‘root‘) where User =‘root‘ 7 -> ; 8 Query OK, 4 rows affected (0.06 sec) 9 Rows matched: 4 Changed: 4 Warnings: 0 10 11 12 13 ysql> select user,password from user; 14 +------------------+-------------------------------------------+ 15 | user | password | 16 +------------------+-------------------------------------------+ 17 | root | *81F5E21E35407D884A6CD4A731AEBFB6AF209E1B | 18 | root | *81F5E21E35407D884A6CD4A731AEBFB6AF209E1B | 19 | root | *81F5E21E35407D884A6CD4A731AEBFB6AF209E1B | 20 | root | *81F5E21E35407D884A6CD4A731AEBFB6AF209E1B | 21 | debian-sys-maint | *422D1AF27E5E185185FE7E0C56187AB7396542D0 | 22 +------------------+-------------------------------------------+ 23 5 rows in set (0.00 sec) 24 25 mysql>