Screen brightness using Fn keys in i3wm
I got a new laptop for work, Lenovo Thinkpad X260. Installed Ubuntu 16.04 Xenial Xerus and i3wm without much problem.
There are several Fn-hotkeys for the F1-F12 keys, most of them do not work out of the box in Ubuntu, at least not when running i3-window manager.
I managed to solve it in the end. This is how. Part of this solution is from
Thanks for that!
Changing the brightness
I figured out that the brightness can be changed with
sudo echo VALUE > /sys/class/backlight/intel_backlight/brightness
where VALUE is between 0 and what is given by the output
These paths might be different for you, so you have to figure it out, and edit the paths in the script below to fit your needs.
So I created a script that changes the brightness, as mentioned it borrows heavily from the above mentioned page, but there are some changes.
I save it as
brightness_control in some place, perhaps in your bin folder or something.
The script is as follows:
#!/bin/bash # script to control the brightness of a Lenovo Thinkpad X260 # in i3wm (Ubuntu Linux) using the Fn-hotkeys # Magnus Persson, with help from # http://ttrmw.co.uk/linux/hardware_button_brightness.html # how much we change the brightness is the input parameter change=$1 echo $change # get the maximum brightness value max_brightness=$(cat /sys/class/backlight/intel_backlight/max_brightness) echo $max_brightness # get the current brightness brightness=$(cat /sys/class/backlight/intel_backlight/brightness) echo $brightness # calculate the new value that is requested. # if input is negative it will subtract (?) new_value=$(($brightness + $change)) echo $new_value # if the new value is less than 1, we just set it to 1 # 0 is completely pitch black, just put pc to sleep # if you want that. if (( $new_value < 10 )); then let brightness=10 # if the new value is greater than max brightness, set it to max brightness elif (($new_value > $max_brightness)); then let brightness=$max_brightness # if none of the above if-statements are true, just set it to the # new brightness value else let brightness=$new_value fi # now we can just echo the value into the brightness acpi(?) file echo $brightness > /sys/class/backlight/intel_backlight/brightness #| bash #or zsh, csh or whateva
To run the program it needs super user (sudo) privileges. So to run it without it we need to add it to the visudo file. To do this, run
sudo visudo and add, to the end of the file
your_user your_machine = NOPASSWD: /path/to/brightness_control
Now this makes it possible to run the script as before, but it wont ask for a password
sudo ./brightness_control -400, to lower the brightness 400 units )
Give your file to root
So we just give it to the root user with
sudo chown root:root brightness_control and
sudo chmod 0711 brightness_control,now you can run the script without filling in the password, but to edit it you need to put the sudo password in.
i3 window manager – binding the Fn-hotkeys
xevand click your brightness up/down Fn-hotkey combination, or alternatively you run
xmodmap -pk | grep Brightness. For me this last command shows (should be similar for the former command):
232 0x1008ff03 (XF86MonBrightnessDown) 0x0000 (NoSymbol) 0x1008ff03 (XF86MonBrightnessDown) 233 0x1008ff02 (XF86MonBrightnessUp) 0x0000 (NoSymbol) 0x1008ff02 (XF86MonBrightnessUp) 237 0x1008ff06 (XF86KbdBrightnessDown) 0x0000 (NoSymbol) 0x1008ff06 (XF86KbdBrightnessDown) 238 0x1008ff05 (XF86KbdBrightnessUp) 0x0000 (NoSymbol) 0x1008ff05 (XF86KbdBrightnessUp)
Here Mon is for monitor, and Kbd for keyboard (the backlit keyboard).Now I have in my
# Brightness control (without any fuzz) bindsym XF86MonBrightnessUp exec --no-startup-id sudo /home/user/scripts/brightness_control +100 bindsym XF86MonBrightnessDown exec --no-startup-id sudo /home/user/scripts/brightness_control -100
Shift+Super+r, to reload i3 and then just hit brightness up/down to control brightness on your X260 in the awesome i3 tiling window manager.
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