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

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 
of the features defined in the EWMH specification. 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 the
number of desktops, make windows full-screen, always-above, or sticky, and
activate, close, move, resize, maximize, and minimize them. The command line
access makes it easy to automate these tasks and execute them from any
application that is able to run a command in response to some event.