How to change mysql root password?

Its very simple:-

[root@atta ~]# mysqladmin -u root -p'old-password' password 'New-Password' 

To change:-  eg.

[root@atta ~]# mysqladmin -u root -p'asdf' password '12345' 

How to Login MySQL root account:-

[root@atta ~]# mysqladmin -u root -p'your-password'

How to set the MySQL root password:-

                              This method works only if root password is blank.

[root@atta ~]# mysqladmin -u root 'new-password'