How to change hostname in Ubuntu 17.04 Zesty Zapus

 

Hostname can be changed in Ubuntu 17.4  manually by editing this files
/etc/hostname
&
/etc/hosts
and then restarting Hostname Service by

service hostname restart
It sometimes produces errors like

Failed to restart hostname.service: Unit hostname.service is masked.

Best Method for new versions of Ubuntu is:

sudo hostnamectl set-hostname NewHostName

Its work very well and produces no error.