System
>Administration
>Login Screen Setup
Enable XDMCP
Close
the windowTerminal.app
/usr/X11R6/bin/X -query XXX.XXX.XXX.XX
where XXX.XXX.XXX.XXX is the IP of the Ubuntu machineXquartz
and a few seconds after you should see the Ubuntu login screen appear.Xquartz.app
icon in the dock to get Ubuntu back.Terminal.app
in OS X and hit CONTROL + C
to quit Xquartz.app
.