Set a custom resolution using xrandr (even if the resolution currently does not exist)

resolution.sh

#!/bin/sh

set -eux

width=${1:-2560}
height=${2:-1080}

newresandrate="$width $height 60"

modeline=`cvt $newresandrate | grep Modeline | sed 's/Modeline //g'`
modetitle=`echo $modeline | grep -o "\"[^\"]*\""`

connected_device=`xrandr | grep -e " connected [^(]" | sed -e "s/\([A-Z0-9]\+\) connected.*/\1/"`

echo $modeline
echo $modetitle
echo $connected_device

if [[ `xrandr | grep $modetitle | wc -l` -lt 1 ]]; then
	echo "Adding the new mode to xrandr"

	sudo xrandr --newmode $modeline
	sudo xrandr --addmode $connected_device $modetitle
fi

xrandr -s ${width}x${height}