I am running Ghostbsd 20.03. I installed the powerdxx pkg- https://www.freshports.org/sysutils/powerdxx/
I followed the instructions as presented in the URL https://github.com/lonkamikaze/powerdxx
When I run:
service powerd stop - it works
service powerd disable - it does not work. The following is presented- powerd: unknown function `disable'

I have reviewed the man page for powerd and found no assistance there with my issue.
Also, I have searched this forum for a solution.

In /etc/r.conf, I inserted:
powerd_enable="NO"
powerdxx_enable="YES"
When I restart the machine and login, I note that powerd still appears as a running process
and powerdxx is not running as a process.

Currently I am using a simple alias to accomplish this after I have logged in.
sudo service powerd stop && sudo service powerd++ start

How do I disable the service powerd and enable the service powerdxx at startup?

Hi, I think this should help you:

https://wiki.ghostbsd.org/index.php/Rc-update
"
if you want a service starting at boot write as root:
rc-update add foo
or
rc-update add foo default
If a service don't have to start at boot write:
rc-update delete foo
"

Thank you for your quick response.
As root:
I ran rc-update delete powerd and received - "rc-update: service `powerd' is not in the runlevel `default'
Once I stopped the service, the rc-update delete powerd command worked.
The add command worked.
When you run rc-status, the services are on the extreme left and the respective statuses are on the extreme right.
So much information is poorly displayed in the terminal.
Therefore, I installed Webmin to provide a GUI to eliminate this and it provides a clear view of what is happening.