Permanent hostname change on Debian based systems

From MDLog:/sysadmin:
Debian based systems use the file /etc/hostname to read the hostname of the system at boot time and set it up using the init script /etc/init.d/hostname.sh
/etc/hostname:

server

So on a Debian based system we can edit the file /etc/hostname and change the name of the system and then run:

/etc/init.d/hostname.sh start

to make the change active. The hostname saved in this file (/etc/hostname) will be preserved on system reboot.