Set / change / reset the MySQL root password on Ubuntu Linux. Enter the following lines in your terminal.
1. Stop the MySQL Server.
sudo /etc/init.d/mysql stop
2. Start the mysqld configuration.
sudo mysqld --skip-grant-tables &
3. Login to MySQL as root.
mysql -u root mysql
4. Replace YOURNEWPASSWORD with your new password!
UPDATE user SET Password=PASSWORD('YOURNEWPASSWORD') WHERE User='root'; FLUSH PRIVILEGES; exit;
Reference: http://dev.mysql.com/doc/refman/5.0/en/resetting-permissions.html