Creating script to adjust the brightness level of the monitor

[Catalyst2Death]

Hello,

I am running ubuntu gutsy on a Dell inspiron 1501. My fn brightness keys don't work, and I don't want to downgrade my bios (in fact, I can't because I'm running ubuntu/vista and the downgrade software only works in xp and earlier)

So, I'm wondering if it is possible to write a shell script to adjust the brightness (one for up and another for down) and then bind them to keys on the keyboard (like alt+up or alt+down to increase and decrease brightness respectively)

this would circumvent the use of the fn key, but I don't have a clue how to begin to implement something like this

[mridkash]

Do you know the commands to use for brightness. Can you do it in terminal?

If yes then you can make a bash script and run it on some key combination.

[moma]

Just a tiny idea.

Check if the XRandr (http://www.x.org/wiki/Projects/XRandR) utility can change the brightness value.

Check
$ man xrandr

and Google for "xrandr brightness"
----

Notice also that most of the graphic cards (drivers) have their own command line and GUI config tools.
Such as ATI has "aticonfig".
NVIDIA has "nvidia-settings" and "nvidia-xconfig"
----

Related stuff, URandR: http://albertomilone.com/wordpress/?p=142

Merry Christmas
$ xsnow

[Catalyst2Death]

I googled "xrandr" and it looped my back here! oh well, thanks for the advice.
I know the command for brightness, the only problem is that you must be logged on as root to adjust the brightness... sudo doesn't work, anyway how do I do this?

I'm not entirely familiar with shell scripts, so I don't know how to get it to login as root and then adjust brightness. I would like to just press alt+up and have the brightness incrementally change, but I don't have a clue how to get going.

[mridkash]

to set custom keyboard shortcuts,

in terminal,

gconf-editor

a config editor window will open. Browse to apps> metacity> global keybindings
here you'll see "run_command_#" textboxes. type the shortcut in the value box. To set the commands, browse to keybindings_command and type the command.

it will work if you have desktop effects disabled. If you have compiz enabled then you have to install ccsm package to edit shortcuts.

[deuce868]

If you feel like playing with DBus programming, there seems to be a dbus interface to the power manager.

org.freedesktop.PowerManagement

Not sure what language you wanted to work on a script in, but python and dbus are pretty simple and you could write up a script to change the setting from there.

[stevew45]

I googled "xrandr" and it looped my back here! oh well, thanks for the advice.
I know the command for brightness, the only problem is that you must be logged on as root to adjust the brightness... sudo doesn't work, anyway how do I do this?

I'm not entirely familiar with shell scripts, so I don't know how to get it to login as root and then adjust brightness. I would like to just press alt+up and have the brightness incrementally change, but I don't have a clue how to get going.

I have the same sort of problem, no fn keys. What commands do you use to adjust brightness from within the terminal?

[deuce868]

I use this script I call 'powermode'. I call it with either:

disable
powermode d

partial
powermode p

all
powermode a



#!/bin/bash
if test "$1" = "a"
then
sudo -v
cpu_speed set powersave && sudo echo -n 20 | sudo tee /proc/acpi/video/VID/LCD0/brightness

# turns a noatime mount
mount -o remount,noatime /home
mount -o remount,noatime /
elif test "$1" = "p"
then
sudo -v
cpu_speed set conservative && sudo echo -n 60 | sudo tee /proc/acpi/video/VID/LCD0/brightness

# turns a noatime mount
mount -o remount,noatime /home
mount -o remount,noatime /
elif test "$1" = "d"
then
sudo -v
cpu_speed set ondemand && sudo echo -n 100 | sudo tee /proc/acpi/video/VID/LCD0/brightness
else
echo "Usage:"
echo " $(basename $0) a # all out powersave mode"
echo " $(basename $0) p # powersave"
echo " $(basename $0) d # disable powersave modes"
fi
echo ""


It's the setting in /proc/acpi/video/VID/LCD0/brightness that adjusts the backlight.

[haldean]

You should look into the xbacklight tool -- the syntax is incredibly easy, and it's in the repos. It's as simple as:



xbacklight = 0 # Turn off backlight
xbacklight = 50 # Backlight at 50%
xbacklight = 100 # Backlight at full
xbacklight - 20 # -20%
xbacklight + 10 # +10%


I know this is an old thread, but it's also the first Google result for "backlight shell script", and I thought this was useful.