Use mysqladmin command to change root password
If you have never set a root password for MySQL server, the server does not require a password at all for connecting as root. 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 newpass For example, If the old password is abc, you can set the new password to 123456, enter:
$ mysqladmin -u root -p'abc' password '123456'
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Reference:
-http://www.cyberciti.biz/faq/mysql-change-root-password/