dsenableroot
that can be used to both enable and disable the root account.The full path is /usr/sbin/dsenableroot and you must be an admin level user to run it. In both cases, you will be prompted for your own user password. When root is enabled, you are prompted to set the root password.
This sequence enables root:
dsenableroot
username = keithw
user password:
root password:
verify root password:
dsenableroot:: ***Successfully enabled root user.
This sequence disables root:
dsenableroot -d
username = keithw
user password:
dsenableroot:: ***Successfully disabled root user.
I generally like to have root enabled. Here is my older post on enabling root.