Since I use this a lot in my daily work and there were no scripts working properly for me, I made one myself.
It's actually not bound to Xfce but should work on any window manager (haven't tried it, though).
Installation
- 
If you don't yet have xdotool, install it:sudo apt-get install xdotool
- 
If you don't yet have wmctrl, install it:sudo apt-get install wmctrl
- 
Store the attached file in some place that's in your PATH.
 The cool kids use~/bin/.
- 
Make it executable: chmod +x ~/bin/move-to-next-monitor
Trying it
Open up a terminal and run it:
move-to-next-monitor
There should be no errors and the terminal window should have moved one monitor to the right.
Assigning a keyboard shortcut
- Your window manager has a way to setup global hotkeys somewhere. In Xfce you may open Xfce settings → Keyboard → Keyboard shortcuts
- Add an entry for move-to-next-monitorand assign a keyboard shortcut to it.
- It should be active right away, so try it on the settings window. :)
Done!
Props to icyrock.com who had a script that was basically working (not properly on 3 monitors and was lacking some workarounds) and saved me quite some time figuring this all out.
Posted by Arne Hartherz to makandra dev (2012-11-14 14:24)