sudo /etc/init.d/mysql stop

sudo /usr/sbin/mysqld --skip-grant-tables --skip-networking &

mysql -u root

FLUSH PRIVILEGES;

SET PASSWORD FOR root@'localhost' = PASSWORD('password');

UPDATE mysql.user SET Password=PASSWORD('newpwd') WHERE User='root';

FLUSH PRIVILEGES;

sudo /etc/init.d/mysql stop
sudo /etc/init.d/mysql start