The wmctrl program is a command line tool to interact with an
EWMH/NetWM compatible X Window Manager.

It provides command line access to almost all the features defined in
the EWMH specification. Using it, it's possible to, for example, obtain
information about the window manager, get a detailed list of desktops
and managed windows, switch and resize desktops, change number of
desktops, make windows full-screen, always-above or sticky, and
activate, close, move, resize, maximize and minimize them. 

WWW: http://sweb.cz/tripie/utils/wmctrl/