function battery_capacity
    pushd /sys/class/power_supply/
    for dir in ( ls | rg BAT | cut -d" " -f1)
        pushd $dir &&
            cat energy_full | read x &&
            cat energy_full_design | read y &&
            echo "capacity % of $dir compared to design capacity"
        kalker $x/$y &&
            popd
    end
	popd
end