When I connect or disconnect the USB device, udev shows/monitors that event. But udev is not enough smart to detect the plug-out or plug-in of the monitor. Is there any way/tool/utility from which I will get real-time information about the plug-out or plug-in of a monitor?
I think there is no daemon for that. You could however write a script to periodically parse xorg.log or you may be able to use xrandr, but I am not at my Linux box right now, so I can't tell exactly.