Set Intel backlight brightness level Linux bash (Samsung NP300V3A-SE07)

setbrightness.sh

#!/bin/bash
#
# Set brightness of intel backlight
# Usage:
#   setbrightness
#     Print current brightness
#   setbrightness <level>
#     Set brightness to <level> 1-10
#   setbrightness less
#     Set brightness to current level - 1
#   setbrightness more
#     Set brightness to current level + 1
#
# Set screen brightness
# Usage: setbrightness more|less|<integer>

DIR="/sys/class/backlight/intel_backlight"
MAX_VALUE=$( < $DIR/max_brightness )
MAX_STEP=8
STEP_AMOUNT=$(( $MAX_VALUE / $MAX_STEP ))
CURRENT_VALUE=$( < $DIR/brightness )
CURRENT_STEP=$(( $CURRENT_VALUE * $MAX_STEP / $MAX_VALUE ))

# Set brightness by step value
function setstep() {
  STEP=$1
  if [[ $STEP -lt 1 || $STEP -gt $MAX_STEP ]]; then
    >&2 echo "Invalid step $STEP. Expected number between 1 and $MAX_STEP".
    exit 1
  fi

  # Set brightness and exit with echo's exit code
  echo $(( $STEP * $STEP_AMOUNT )) > $DIR/brightness
  exit $?
}

if [ -z $1 ]; then
  echo "Current screen brightness is at step $CURRENT_STEP ($CURRENT_VALUE)"
fi

echo $CURRENT_STEP $MAX_STEP $CURRENT_VALUE

case "$1" in
  "more")
    setstep $(( $CURRENT_STEP + 1 ))
    ;;
  "less")
    setstep $(( $CURRENT_STEP - 1 ))
    ;;
  *)
    if [[ "$1" =~ ^[0-9]{1,2}$ ]]; then
      setstep $1
    fi
    ;;
esac

My max brightness (MAX_VALUE) is 4648, which is divisible by 8, which is why my MAX_STEP is 8.

Yeah, this work also on ThinkPad X220