To permanently change the Hostname of your device via the terminal

Set or Change Hostname (via Terminal) - OS X 10.6 - 10.10

• Open Terminal by going to Applications, then Utilities, and select Terminal

• The type the following:

sudo scutil –-set HostName new_hostname
For example: sudo scutil –-set HostName ECE-MAC

Note:  It may also be necessary to perform the following commands to solidify the changes

sudo scutil --set ComputerName <hostname>
For example: sudo scutil --set ComputerName ECE-MAC
sudo scutil --set LocalHostName <hostname>
For example: sudo scutil --set LocalHostName ECE-MAC