#!/bin/bash

PER=$1

case $PER in
    ''|*[!0-9]*)
        #non numeric
        echo "Missing input value 5-100"
        exit 1
        ;;
    *)
        #good
esac

if [ $PER -lt 5 ]; then PER=5; fi

#VAL=$(( $PER / 100 ))
VAL=$(echo "$PER / 100" | bc -l)

xrandr --output HDMI-1 --brightness $VAL

exit