function get_vnc() {
# USAGE: 
#  get_vnc
#  do_your_X11_stuff
#  kill_vnc

    local i
    for ((i=0;$i<60;i++)); do
        vncserver :$i -depth 24 -geometry 1024x768 -geometry 800x600 -geometry 1366x768 -geometry 1280x1024 -geometry 1680x1050 2>&1
        if [ $? -eq 0 ]; then
            VNCDISPLAY=$i
            export DISPLAY=:$i
            VNCPORT=$(( 5900 + $i ))
            echo DISPLAY=$DISPLAY
            echo VNCPORT=$VNCPORT
            return 0
        fi
    done
    # failed to start
    return 1
}
function kill_vnc() {
    vncserver -kill $DISPLAY
}