What does the :0.0 actually mean? I know that :0 is the first X server that is started on a local machine, :1 the second, etc. But what is that .0 part after :0? Do other combinations exist? (e.g. :0.0-something)
Background: I'm trying to improve the initscript of bumblebee which currently assumes that :0 is the active display. That is not the case if I switch users. So I wanted to validate the $DISPLAY variable before passing it to vglclient.
Best Answer
The format of the display variable is
[host]:<display>[.screen].hostrefers to a network host name, and if absent means to connect to the local machine via a unix domain socket.Each host can have multiple displays, and each display can have multiple screens. Screens aren't used much anymore, with xinerama and now xrandr combining multiple screens into a single logical screen.