Use Raspberry Pi as external network-monitor

xtend11.sh

#!/bin/bash
PI_IP="xxx.xxx.xxx.xxx"
LEFT_OF="VGA1" #"LVDS1"
CLIENT_SCRIPT_NAME="x11-client.sh"
LOCKFILE="/tmp/x11-extended-display-lock.pid"

screen_res='python -c "import Tkinter; r = Tkinter.Tk(); print r.winfo_screenwidth(), r.winfo_screenheight(); r.destroy();"'
d=`ssh pi@$PI_IP "export DISPLAY=:0 && $screen_res"`

case $1 in
	client-gen)
		own_ip=`hostname --ip-address`
		ssh pi@$PI_IP -t "echo 'export DISPLAY=:0 && sleep 3 && xdotool mousemove 0 0 && vncviewer $own_ip -fullscreen' > $CLIENT_SCRIPT_NAME && chmod +x $CLIENT_SCRIPT_NAME"
		exit;;
	background)
		if [ -e $LOCKFILE ]
		then
			echo "Process already running"
			exit
		else
			echo $$ > $LOCKFILE
		fi;;
	*)
		screen -S x11_server -d -m $0 background
		exit;;
esac

ssh pi@$PI_IP "screen -S x11_client -d -m ./$CLIENT_SCRIPT_NAME"

mm=`cvt $d 60`
m=${mm##*Modeline }
mn="$( cut -d ' ' -f 1 <<< "$m" )"

xrandr --newmode $m
xrandr --addmode VIRTUAL1 $mn
xrandr --output VIRTUAL1 --mode $mn --left-of $LEFT_OF
x11vnc -display :0 -auth /var/lib/gdm/:0.Xauth
xrandr --output VIRTUAL1 --off

rm $LOCKFILE