Suspend and block screen using comman line in Ubuntu 9.10

dbus-send --session --dest=org.gnome.ScreenSaver --type=method_call /org/gnome/ScreenSaver org.gnome.ScreenSaver.Lock ; dbus-send --print-reply --system --dest=org.freedesktop.DeviceKit.Power /org/freedesktop/DeviceKit/Power org.freedesktop.DeviceKit.Power.Suspend