As root:
Code:
hostname `cat /etc/myname`
You may need to log-out and back in, to see it in your prompt (if you have it set as part of your prompt)... but that command will change it. You don't "need" to log-out, I personally have it as part of my prompt and usually want that accurate so I will.
It's actually the command run by the netstart script to set it in the first place.