#!/bin/bash

XWIDTH="$(xrandr 2>/dev/null | grep '*' | sed -r 's/^\s+([0-9]+)x.*/\1/')"
XHEIGHT="$(xrandr 2>/dev/null | grep '*' | sed -r 's/^\s+[0-9]+x([0-9]+).*/\1/')"

WIDTH="$(echo "${XWIDTH}*92/1024" | bc)"
HEIGHT="$(echo "${XHEIGHT}*32/768" | bc)"

sed -i -r "s/(URxvt.geometry:\s+).*/\1${WIDTH}x${HEIGHT}+24+24/" ~/.Xresources
xrdb -merge ~/.Xresources