When I execute an application with xvfb-run, I can either explicitly specify an X11 server number (i.e. 44), or I can use --auto-servernum, which will assign one for me.
If I use --auto-servernum, how do I know what number it picked?
I'm trying to use this in a script, so if xvfb-run could output that somewhere so that I can use subsequent commands on the right X11 server, that'd be helpful.