Hostname is the identification or identity for the host (computer or other network device) name. The name will be recognized by other hosts that are in a network where the host is connected both in LAN or WAN.
In the linux operating system is actually at the moment of the installation process of the linux machine, you will be prompted to enter the name of the hostname. However, if at any time a user or administrator wants to change the name of the hostname will be done in the following way:
1. you must enter your terminal /shell
You must be logged in as root (superuser), since to revamp a system of rights owned by the super user.
2. use your favorite editor, if I prefer to open the editor in root mode is a good idea anyway and use a text-based editor like VI, nano, emacs, and others.
3. Edit the file ( I use VI editor ) vi "/etc/hostname"
then save (escape: wq!)
4. then log off your computer, and then log back on.
Then you open terminal again and then typing "hostname" then the name of your computer's hostname will be changed.
Many thanks and hopefully useful