14.04 LTS
配置/etc/mysql/my.cnf,在[mysqld]下加入一行 skip-grant-tables
sudo service mysql restartmysql
mysql> use mysql
mysql>update user set password=PASSWORD("new_password") where user='root'; 新密码为new_password
vim /etc/mysql/my.cnf,注释skip-grant-table
sudo service mysql restart。