Ubuntu 18.04 Backlight Control Command Line

By default the xbacklight command does not work on Intel HD Graphics:

Workaround:

sudo nano /usr/share/X11/xorg.conf.d/10-intel.conf:

insert:

Section "Device"
Identifier "Card0"
Driver "intel"
Option "Backlight" "/sys/class/backlight/intel_backlight"
EndSection

now add to startup / autostart (lxde) :
xbacklight -set 30