Configure brightness control keys

On a Lenovo Thinkpad X230 netbook, the Fn+F8/F9 keys did not change the screen brightness. The following procedure resolves this issue.

1. Package installation

2. Hardware permissions configuration (udev)

Create the file:

sudo nano /etc/udev/rules.d/90-backlight.rules   ~ nano or vim or mcedit or vi or le (text editor)

Add the following line:
ACTION=="add", SUBSYSTEM=="backlight", KERNEL=="intel_backlight", GROUP="video", MODE="0664"

3. Keyboard shortcuts configuration (Openbox)
Edit the files:

/etc/xdg/openbox/rc.xml and /.config/openbox/lxde-rc.xml

Insert inside the <keyboard> section:

<keybind key="XF86MonBrightnessUp">
<action name="Execute">
<command>brightnessctl set +5%</command>
</action>
</keybind>
<keybind key="XF86MonBrightnessDown">
<action name="Execute">
<command>brightnessctl set 5%-</command>
</action>
</keybind>

4. Default user profile installation (skel)

5. Reboot