MySQL change root password
To change the root password for the database in linux you use mysqladmin utility. The parameters you need to pass are: -u root the username used for logging in. In this case we want to be root obviously -p'currentPassword' the password for logging in. Notice there are no space between p and quote. password newPassword define the new password.
So for example: mysqladmin -u root -p'myoldpassword' password mynewpassword