没有过忘记密码的程序员是不完美的，对于Oracle忘记密码可以设置orapwdfile文件，
Mysql其中一种方法是通过修改文件免密然后再进行密码的修改：
1.忘记密码
[root@leader ~]# mysql -uroot -p
Enter password:
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)
[root@leader ~]#
2.修改文件/etc/my.cnf
修改文件前先停掉mysqld服务
[root@leader ~]# service mysqld stop
Stopping mysqld: [ OK ]
[root@leader ~]#vi /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
skip-grant-table ##添加该参数跳过密码验证
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
3,重启服务进行密码修改
[root@leader ~]# service mysqld start
Starting mysqld: [ OK ]
[root@leader ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or g.
Your MySQL connection id is 2
Server version: 5.1.73 Source distribution
Copyright (c) 2000, 2013, 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> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| test |
+--------------------+
3 rows in set (0.00 sec)
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('mysql123')where user='root' and host='localhost';
Query OK, 0 rows affected (0.00 sec)
Rows matched: 1 Changed: 0 Warnings: 0
mysql>