brightctl

#!/bin/bash

# Check if running with root permissions
if [ "$EUID" -ne 0 ]; then
    echo "This script requires root permissions. Please run it with sudo or doas."
    echo "Example: sudo $0 [options]"
    echo "         doas $0 [options]"
    exit 1
fi

# Define the maximum and minimum brightness values
max_brightness=400
min_brightness=0

# Get the current brightness value
current_brightness=$(cat /sys/class/backlight/intel_backlight/brightness)

# Function to print usage
usage() {
    echo "Usage: $0 [-s|--set VALUE] [-i|--inc VALUE] [-d|--dec VALUE] [-h|--help] [-c|--current]"
    echo "  -s, --set VALUE    Set the brightness value (between $min_brightness and $max_brightness)"
    echo "  -i, --inc VALUE    Increase the brightness by VALUE (between $min_brightness and $max_brightness)"
    echo "  -d, --dec VALUE    Decrease the brightness by VALUE (between $min_brightness and $max_brightness)"
    echo "  -h, --help         Display this help and exit"
    echo "  -c, --current      Display the current brightness value and exit"
}

# Parse options
if [ "$#" -eq 0 ]; then
    usage
    exit 0
fi

while [[ $# -gt 0 ]]; do
    case "$1" in
        -s|--set)
            new_brightness="$2"
            shift 2
            ;;
        -i|--inc)
            new_brightness=$((current_brightness + $2))
            shift 2
            ;;
        -d|--dec)
            new_brightness=$((current_brightness - $2))
            shift 2
            ;;
        -h|--help)
            usage
            exit 0
            ;;
        -c|--current)
            echo "Current brightness value: $current_brightness"
            exit 0
            ;;
        *)
            usage
            exit 1
            ;;
    esac
done

# Ensure the new brightness value is within the valid range
new_brightness=$((new_brightness < min_brightness ? min_brightness : new_brightness))
new_brightness=$((new_brightness > max_brightness ? max_brightness : new_brightness))

# Write the new brightness value to the brightness file
echo "$new_brightness" > /sys/class/backlight/intel_backlight/brightness

# Print the new brightness value
echo "New brightness value: $new_brightness"