Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
Brightness control with Intel chipsets (ThinkPad etc.)
#!/bin/bash
#
# Shows and optionally adjusts Intel screen brightness
#
# Run from command line or bind to shortcut keys
#
# Usage: brightness [up|down]
#
# by: Runar Balstad Jensen
# url: https://gist.github.com/emning/5d3301a3f3c9420414f7
# ref: http://askubuntu.com/q/428237
#
DEV=/sys/class/backlight/intel_backlight
STEPS=17 # 17 * 50 = 850, and 851 is the max for my Intel device
FUDGE=3 # round up or down if within this much of 0 or MAX
sudo_if_needed()
{
test $UID = 0 || echo sudo
}
get_brightness()
{
CUR=$(cat $DEV/brightness)
MAX=$(cat $DEV/max_brightness)
}
set_brightness()
{
val=$1
if [[ $val -le $FUDGE ]]
then
val=0
fi
if [[ $val -ge $((MAX - FUDGE)) ]]
then
val=$MAX
fi
$(sudo_if_needed) tee $DEV/brightness <<< $val > /dev/null
}
print_brightness()
{
echo "$CUR/$MAX ($(((CUR * 100) / MAX)) %)"
}
if [[ $# -eq 1 ]]
then
get_brightness
case "$1" in
up)
set_brightness $((CUR + (MAX / STEPS)))
;;
down)
set_brightness $((CUR - (MAX / STEPS)))
;;
esac
fi
get_brightness
print_brightness
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment