Mine

#!/bin/bash

CurrentValue=`cat /proc/acpi/video/VGA/LCD/brightness | tail -1 | cut -d" " -f2`

Set1=12
Set2=25
Set3=37
Set4=50
Set5=62
Set6=75
Set7=87

if [ $CurrentValue = "0" ]; then
        echo "Changing to brightness 1"
        echo $Set1 > /proc/acpi/video/VGA/LCD/brightness
elif [ $CurrentValue = $Set1 ]; then
        echo "Changing to Brightness 2"
        echo $Set2 > /proc/acpi/video/VGA/LCD/brightness
elif [ $CurrentValue == $Set2 ]; then
        echo "Changing to Brightness 3"
        echo $Set3 > /proc/acpi/video/VGA/LCD/brightness
elif [ $CurrentValue == $Set3 ]; then
        echo "Chaning to Brightness 4"
        echo $Set4 > /proc/acpi/video/VGA/LCD/brightness
elif [ $CurrentValue == $Set4 ]; then
        echo "Chaning to Brightness 5"
        echo $Set5 > /proc/acpi/video/VGA/LCD/brightness
elif [ $CurrentValue == $Set5 ]; then
        echo "Chaning to Brightness 6"
        echo $Set6 > /proc/acpi/video/VGA/LCD/brightness
elif [ $CurrentValue == $Set6 ]; then
        echo "Chaning to Brightness 7"
        echo $Set7 > /proc/acpi/video/VGA/LCD/brightness
elif [ $CurrentValue == $Set7 ]; then
        echo "Laptop already set at brightness 7"
elif [ $CurrentValue == "100" ]; then
        echo "Value is at 100, this brighter than brightness 7"
else
        echo "UnKnown error..."
fi