The xkill(1) utility forces the X server to close
connections to clients. This program is very dangerous, but is
useful for aborting programs that have displayed undesired windows
on a user's screen. If no resource identifier is given with
-id, xkill(1) will display a special cursor as a
prompt for the user to select a window to be killed. If a pointer
button is pressed over a non-root window, the server will close its
connection to the client that created the window.
This option indicates that all clients with top-level windows
on the screen should be killed. The xkill(1) utility will
ask you to select the root window with each of the currently
defined buttons to give you several chances to abort. Use of this
option is highly discouraged.
-buttonnumber
This option specifies the number of pointer button that should
be used in selecting a window to kill. If the word "any" is
specified, any button on the pointer can be used. By default, the
first button in the pointer map (which is usually the leftmost
button) is used.
-displaydisplayname
This option specifies the name of the X server to contact.
-frame
This option indicates that xkill should ignore the
standard conventions for finding top-level client windows (which
are typically nested inside a window manager window), and simply
believe that you want to kill direct children of the root.
-idresource
This option specifies the X identifier for the resource whose
creator is to be aborted. If no resource is specified,
xkill(1) will display a special cursor with which you should
select a window to be kill.