usage:  /usr/bin/xdpyinfo [options]
-display displayname	server to query
-help			print program usage and exit
-version		print program version and exit
-queryExtensions	print info returned by XQueryExtension
-ext all		print detailed info for all supported extensions
-ext extension-name	print detailed info for extension-name if one of:
     MIT-SHM XKEYBOARD Multi-Buffering SHAPE SYNC XTEST DOUBLE-BUFFER RECORD
     XInputExtension