Can you help me write a script to set a new default brightness for the screen/keyboard after login?

Question

On my Macbook Pro Ubuntu alsways boots with...

• keyboard brightness at maximum illumination
• screen brightness at maximum illumination

...both which I need almost never during normal usage.

Question

Instead of directly manipulating configuration files, I'm thinking of a solution that would work like a script and set both brightness settings to a lower default. How might this be accomplished?

Unfortunately, I have no experience in scripting and would be glad if you can help me out here.

---

I've figured out what needs to be done to change both the screen brightness and the keyboard backlight. Can you help be to make this a script that is automatically run at login?

Change Keyboard backlight

echo 130 | sudo tee -a /sys/class/leds/smc::kbd_backlight/brightness

...where 255 is the maximum brightness and 0 is the lowest brightness.

Change screen brightness

echo 42311 | sudo tee /sys/class/backlight/gmux_backlight/brightness 

...where 4126 is the lowest brightness and 82311 the hightest.

---

I've noticed a another problem.. If I run echo 42311 | sudo tee /sys/class/backlight/gmux_backlight/brightness right after login, but then use the brightness buttons. The screen brightness settings first reset to maximum - and then the change get's applied. This is seems messed up...

Answer 1

You can have root run the brightness commands upon reboot, by adding those commands to /etc/rc.local (gksudo gedit /etc/rc.local), so that it looks like:

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

echo 130 >> /sys/class/leds/smc::kbd_backlight/brightness
echo 42311 > /sys/class/backlight/gmux_backlight/brightness

exit 0

See also Brightness is reset to Maximum on every Restart