At Ubuntu start-up, say you want to to adjust brightness, you can add an upstart job for this.
1. Add a file brightness.conf at /etc/init/ with following lines
description "Job to control brightness at startup"
start on runlevel 
exec intel_backlight 14 # to set brightness to 14%
2. Changes will take effect after restart or by changing run levels.
3. You can start the job by typing:
sudo start brightness or
sudo service brightness start