How to change the hostname in ubuntu

1. open "/etc/hostname" file using text editor
2. command: sudo gedit /etc/hostname
3. modify the existing hostname value with new
4. open "/etc/hosts" file using text editor
5. command:  sudo gedit /etc/hosts
6. modify the existing hostname value with new
7. execute below command to refresh the hostname
8. command: sudo service hostname restart

ubuntu installation using virtualbox