raspberry pi os – Turn PWR LED off

There are many other answers and different methods of controlling the PWR LED.

I developed the following (which I intend to use with cron to control lights on a timer) but can be run from command line (for a user with sudo privileges).

This has been tested on many Pi (from Pi B+ to Pi4) running Stretch and Bullseye

#!/bin/bash
# script to turn PWR LED ON/OFF
# PWRLED or PWRLED OFF turns LED off
# PWRLED anything turns LED ON
# 2023-05-06

ONOFF="$1"
if [ "${ONOFF}" = "" ]; then
ONOFF="0"
else 
if [ "${ONOFF}" = "OFF" ]; then
ONOFF="0"
else 
ONOFF="255"
fi
fi

if [ -e /sys/devices/platform/leds/leds/PWR ]; then
echo $ONOFF | sudo tee /sys/devices/platform/leds/leds/PWR/brightness  > /dev/null
else    # for older OS without leds/PWR
echo $ONOFF | sudo tee /sys/devices/platform/leds/leds/led1/brightness  > /dev/null
fi