output

james@james-Inspiron-N4010:~$ cat /etc/acpi/brightness-up.sh
#!/bin/sh

max=`cat /sys/class/backlight/intel_backlight/max_brightness`
cur=`cat /sys/class/backlight/intel_backlight/actual_brightness`

cur=$((cur + max / 4))

if [ $cur -gt $max ]; then
    cur=$max
fi

echo $cur > /sys/class/backlight/intel_backlight/brightness