# Reset root password

sudo /etc/init.d/mysqld stop  
sudo /etc/init.d/mysqld status  
sudo mysqld\_safe --skip-grant-tables &  
mysql -u root

use mysql;  
update user set password=PASSWORD("mynewpassword") where User='root';  
flush privileges;  
exit

sudo /etc/init.d/mysqld stop  
sudo /etc/init.d/mysqld status  
sudo /etc/init.d/mysqld start  
sudo /etc/init.d/mysqld status

https://support.rackspace.com/how-to/mysql-resetting-a-lost-mysql-root-password/