When I create a new virtual private server (VPS), upon logging in for the first time, I'm presented with something like:
This is fine, but I usually want to change the host name that gets assigned to the instance to something more identifiable than vps4554687.
This can be done with a single command:
hostnamectl set-hostname [YOUR_HOST_NAME]
If you are not logged in as root, it will ask for your sudo password. When logging back in, the command terminal will show [root@your_host_name ~].
(Naturally, another step would be disabling root login, but that's something else.)