how to use xrandr from script?

I am trying to use bash script to add resolution through xrandr and i keep getting error, here is my script:

#!/bin/bash

out=`cvt 1500 800`
out=`echo $out | sed 's/\(.*\)MHz\(.*\)/\2/g'`
input=`echo $out | sed 's/Modeline//g'`
#echo $input
xrandr --newmode $input
input2=`echo $out | cut -d\" -f2`
#echo $input2
xrandr --addmode VNC-0 $input2

when trying to do this manually it works fine. i keep getting from the script cannot find mode... , but when i do xrandr, i do see the new mode