plomlompom.com Git - config/blob - bin/w530_backlight.sh

   1 #!/bin/sh
   2
   3 # A very primitive backlight setter with a hardcoded backlight path, to replace
   4 # xbacklight which currently does not work on my system.
   5
   6 if ! echo "${1}" | egrep -q '^[0-9]+$' && ! [ "${1}" = "+" -o "${1}" = "-" ]; then
   7   echo 'Argument must be a number, or "+", or "-".'
   8   exit 1
   9 fi
  10 backlight_dir=/sys/class/backlight/intel_backlight
  11 max_brightness=$(cat "${backlight_dir}"/max_brightness)
  12 target="${backlight_dir}"/brightness
  13 if [ "${1}" = "+" -o "${1}" = "-" ]; then
  14   fract=$(expr "${max_brightness}" / 20)
  15   cur_brightness=$(cat "${backlight_dir}"/brightness)
  16   brightness=$(expr "${cur_brightness}" "${1}" "${fract}")
  17   if [ "${brightness}" -gt "${max_brightness}" ]; then
  18     brightness="${max_brightness}"
  19   elif [ "${brightness}" -lt "0" ]; then
  20     brightness=0
  21   fi
  22   sudo sh -c 'echo '"${brightness}"' > '"${target}"
  23   exit 0
  24 fi
  25 percentage=${1}
  26 if [ "${percentage}" = '100' ]; then
  27   sudo sh -c 'echo '"${max_brightness}"' > '"${target}"
  28 else
  29   fract=$(expr "${max_brightness}" / 100)
  30   brightness=$(expr "${percentage}" \* "${fract}")
  31   sudo sh -c 'echo '"${brightness}"' > '"${target}"
  32 fi