mysqladmin – To change root password

mysqladmin – To change root password 
To setup root password for first time, use mysqladmin command at shell prompt as follows:

# mysqladmin -u root password NEWPASSWORD

However, if you want to change (or update) a root password, then you need to use the following command:

# mysqladmin -u root -p’OLDPASSWORD’ password NEWPASSWORD

For example, If the old password is xyz123, you can set the new password to 123456, enter:

# mysqladmin -u root -p’xyz123′ password ’123456′