I previously solved the problem by adding a command:
echo X > /sys/class/backlight/intel_backlight/brightness
to /etc/rc.local on Ubuntu 14.04 . But there is no /etc/rc.local on Ubuntu 16.10 . I don't know how to solve it now. Is there a new script that replaces rc.local where I can enter my command?
The standard way to make permanent changes to access points (they are not really files) in /sys is to use sysfsutils rather than /etc/rc.local. The package is not installed by default in 16.10, so first do:
sudo apt install sysfsutils
now edit the file /etc/sysfs.conf, for example:
sudo nano /etc/sysfs.conf
and add this line to the end of it:
class/backlight/intel_backlight/brightness = X
This will do the same as your echo command.
In case you didn't know, rc.local is disabled by default in Ubuntu 16.10, because new versions of Ubuntu use systemd. Thus make rc.local considered a service, but you can anytime turn on rc.local with service command:
sudo systemctl enable rc-local.service
Now that rc.local is enabled, you can use your old workaround, run following command to add desired brightness level to /etc/rc.local :
sudo sed -i '13i echo X > /sys/class/backlight/intel_backlight/brightness ' /etc/rc.local
