The first form of selection own returns the path name of the window in this application that owns selection on the display containing window, or an empty string if no window in this application owns the selection. Selection defaults to PRIMARY and window defaults to ".".
The second form of selection own causes window to become the new owner of selection on window 's display, returning an empty string as result. The existing owner, if any, is notified that it has lost the selection. If command is specified, it is a Tcl script to execute when some other window claims ownership of the selection away from window. Selection defaults to PRIMARY.