"Change Brightness" shell script

chBrightness.sh

#!/bin/bash

function usage {
    cat <<EOF
$(basename ${0}) is a tool for Change a Screen Brightness(Verification environment : Debian7)

Usage:
    $(basename ${0}) [command or options]

Command(Selected Brightness):
    --dark1,-d1        print Dark(Even when "No option")
    --dark2,-d2        print Very Dark
    --dark3,-d3        print Bedroom Dark

Options:
    --version, -v     print $(basename ${0}) version
    --help, -h        print this
EOF
}

function version {
echo "$(basename ${0}) version 0.0.1(Beta) "
}

case ${1} in
    --dark1 | -d1)
        echo 470000 > /sys/class/backlight/intel_backlight/brightness
    ;;
    --dark2 | -d2)
        echo 370000 > /sys/class/backlight/intel_backlight/brightness
    ;;
    --dark3 | -d3)
        echo 240000 > /sys/class/backlight/intel_backlight/brightness
    ;;
    --help | -h)
        usage
    ;;
    --version | -v)
        version
    ;;
    *)
        echo 470000 > /sys/class/backlight/intel_backlight/brightness
    ;;
esac

Change Brightness

"chBrightness.sh" is a tool for Change a Screen Brightness.
Verification environment : Debian7