In order to check the version of a package (either installed or in repository):
apt-get install apt-show-versions
apt-show-versions -a <package>
apt-get install apt-show-versions
apt-show-versions -a <package>
sysctl kernel.hostname
To change it:
sysctl kernel.hostname=NewHostname
Or better edit /etc/hostname
Also don't forget to edit /etc/hosts to prevent sudo showing stupid "unable to resolve" error.