I needed this information earlier for CentOS (which Trixbox uses) and found it on this page: http://rutmandal.info/infotalk/2008/07/10/change-host-name-for-trixbox-shell/

Re-posting here so I don't forget...

Changing hostname commands --

[trixbox1.localdomain ~]# sysctl kernel.hostname

kernel.hostname = trixbox1.localdomain

[trixbox1.localdomain ~]# sysctl kernel.hostname=veejansh.ivr

kernel.hostname = veejansh.ivr

You also need to edit your network file to make this change permanent i.e. persistent across reboots.

[veejansh.ivr ~]# vi /etc/sysconfig/netowrk

Here, edit “HOSTNAME” to “veejansh.ivr”, and save the file.

Now, restart your shell and you will have new name for your shell prompt or HOSTNAME.