Nearly Headless Macbook

What?

I have a old macbook running as a server. i dont want to blow out the display so i want it to shut off after a couple of seconds. i dont run X so i dont have any tooling running.

Lets hack the planet!

Dependencies

apt install evtest

Script

#!/bin/bash

BRIGHTNESS_PATH="/sys/class/backlight/intel_backlight"
# IDLE_SECONDS=300  # 5 minutes
IDLE_SECONDS=30
BRIGHTNESS_OFF=0

TIMESTAMP_FILE="/tmp/last_input_activity"

# Store max brightness
MAX_BRIGHTNESS=$(cat "$BRIGHTNESS_PATH/max_brightness")

# Write current time to timestamp file
touch "$TIMESTAMP_FILE"
date +%s > "$TIMESTAMP_FILE"

monitor_input() {
    local device=$1
    evtest "$device" | while read -r line; do
        if [[ "$line" == *"Event"* ]]; then
            date +%s > "$TIMESTAMP_FILE"
        fi
    done
}

# Start background monitors (adjust devices to match your keyboard/mouse)
monitor_input /dev/input/event4 &  # ← change if needed
# monitor_input /dev/input/event3 &  # ← change if needed

# Main idle check loop
while true; do
    if [[ -f "$TIMESTAMP_FILE" ]]; then
        LAST_ACTIVITY=$(cat "$TIMESTAMP_FILE")
    else
        LAST_ACTIVITY=$(date +%s)
    fi

    NOW=$(date +%s)
    IDLE_TIME=$((NOW - LAST_ACTIVITY))
    CUR_BRIGHTNESS=$(cat "$BRIGHTNESS_PATH/brightness")

    if [ "$IDLE_TIME" -ge "$IDLE_SECONDS" ]; then
        if [ "$CUR_BRIGHTNESS" -ne "$BRIGHTNESS_OFF" ]; then
            echo "$BRIGHTNESS_OFF" | sudo tee "$BRIGHTNESS_PATH/brightness" > /dev/null
        fi
    else
        if [ "$CUR_BRIGHTNESS" -eq "$BRIGHTNESS_OFF" ]; then
            echo "$MAX_BRIGHTNESS" | sudo tee "$BRIGHTNESS_PATH/brightness" > /dev/null
        fi
    fi

    sleep 2
done

SystemD

[Unit]
Description=Idle screen dimmer (evtest-based)
After=multi-user.target

[Service]
ExecStart=/home/xantios/DisplayHack/script.sh
Restart=always

[Install]
WantedBy=multi-user.target

chmod +x ./script.sh

sudo systemctl daemon-reexec
sudo systemctl enable input-idle-dimmer.service
sudo systemctl start input-idle-dimmer.service

Xantios/macbook-display.md

What?

Dependencies

Script

SystemD