We are going to use nano to edit the file.
as always sudo if you’re not root

Lets update;

apt-get update

apt-get upgrade

Now install nano

apt-get install nano

how to use nano?
CTRL+o: this will save the file
CTRL+x: this will exit the file
CTRL+w: this will allow you to enter a phrase to search the file
CTRL+k: this will allow you to cut 1 or more lines of text
CTRL+u: this will allow you to uncut lines of text that were cut using CTRL k (similar to pasting text)
CTRL+v: this will advance the file to the next page
CTRL+y: this will move the file to the previous page
CTRL+t: this will run spellcheck on the file

Now change hostname in Ubuntu or any Debian variant Linux, modify the /etc/hostname and /etc/hosts.

sudo nano /etc/hostname

Change the old hostname to a new hostname.

sudo nano /etc/hosts

Change the oldhostname to a new hostname,

000.00.0.00             newhostname

After changing the /etc/hostname and /etc/hosts, you need to restart the hostname service duh..

sudo /etc/init.d/hostname.sh stop

sudo /etc/init.d/hostname.sh start

Is it working? why not find out;log out,login, SSH and type

hostname

Best of luck!
www.mrvinux.com