Changing root password?

[srehrlich-Re5JQEeQqe8AvxtiuMwx3w at public.gmane.org (Scott Ehrlich)]

I've googled and cannot find a good answer (it's probably out there,
just haven't found it yet...)

In the Windows world, at least as admin, you can invoke a command
prompt, type: net user account_of_choice password_of_choice, and the
password of account_of_choice is changed to password_of_choice, clear
text, yes, but Windows doesn't force a verification of the password.

What is the equivalent method for an up-to-date Linux distro Centos?  Ubuntu?

Thanks.

Scott