bin/bl

#!/usr/bin/env sh
#
# pbrisbin 2014 - adjust backlight brightness. Must be run as root.
#
###
directory=/sys/class/backlight/intel_backlight

cur=$(cat "$directory"/brightness)
max=$(cat "$directory"/max_brightness)
amt=$((max/10))
val=$cur

case "$1" in
  u) val=$((cur+amt)) ;;
  d) val=$((cur-amt)) ;;
  m) val=$max         ;;
  *) { printf "usage: bl [u|d|m]\n" >&2; exit 64; } ;;
esac

# Bounds check
[ $val -gt $max ] && val=$max
[ $val -lt 0    ] && val=0

echo $val > "$directory"/brightness