ybacklight
It's no xbacklight.
Why?
Maybe you can't set your brightness via xbacklight
but are able to change the brightness by manually modifying the files under /sys/class/backlight
How?
Since ybacklight
aims to be a xbacklight
replacement, expect to find similar CLI behaviour (for the functionality that's easy to implement):
Usage:
-set <value> # Set brightness to given percentage
-inc <value> # Increase brightness by the given percentage
-dec <value> # Increase brightness by the given percentage
-get # Get the brightness percentage
-raw_set <value> # Set absolute brightness (maximum depends on the system)
-raw_get # Get absolute brightness (maximum depends on the system)