xdpyinfo - display information utility for X
xdpyinfo [-display displayname] [-queryExtensions] [-ext extension-
Xdpyinfo is a utility for displaying information about an X server. It
is used to examine the capabilities of a server, the predefined values
for various parameters used in communicating between clients and the
server, and the different types of screens and visuals that are
By default, numeric information (opcode, base event, base error) about
protocol extensions is not displayed. This information can be obtained
with the -queryExtensions option. Use of this option on servers that
dynamically load extensions will likely cause all possible extensions
to be loaded, which can be slow and can consume significant server
Detailed information about a particular extension is displayed with the
-ext extensionName option. If extensionName is all, information about
all extensions supported by both xdpyinfo and the server is displayed.
If -version is specified, xdpyinfo prints its version and exits,
without contacting the X server.
DISPLAY To get the default host, display number, and screen.
X(7), xprop(1), xrdb(1), xwininfo(1), xrandr(1), xdriinfo(1),
Jim Fulton, MIT X Consortium
Support for the XFree86-VidModeExtension, XFree86-DGA, XFree86-Misc,
and XKB extensions added by Joe Moss