Turn on/off Raspberry Pi 2 Model B POWER LED

led_ctl

#!/bin/bash

if [[ $# -eq 0 || "$1" == "-h" || "$1" == "--help" ]]; then
  echo "Usage: led_ctl [on|off|auto]"
  echo "on   -- turn POWER LED on"
  echo "off  -- turn POWER LED off"
  echo "auto -- turn POWER LED on if between 08:00 and 20:00, else turn off"
  echo "Run as root."
  exit 0
fi

if [[ $EUID -ne 0 ]]; then
  echo "ERROR: Must run as root"
  exit 1
fi

function turn_pwr_led_off {
  echo 0 > /sys/class/leds/led1/brightness
}

function turn_pwr_led_on {
  echo 1 > /sys/class/leds/led1/brightness
}

if [[ "$1" == "off" ]]; then
  turn_pwr_led_off
fi

if [[ "$1" == "on" ]]; then
  turn_pwr_led_on
fi

if [[ "$1" == "auto" ]]; then
  now=$(date +"%H%M")
  if [[ 800 -le $now && 2000 -ge $now ]]; then
    turn_pwr_led_on
  else
    turn_pwr_led_off
  fi
fi

Put in /usr/local/bin (or anywhere that is on your PATH), and make sure it has the right owner and permissions,

$ sudo chown root:staff /usr/local/bin/led_ctl
$ sudo chmod 755 /usr/local/bin/led_ctl

The staff group is a Debian/Raspbian/Ubuntu/etc. thing; you probably want root:root if you're on a distro which isn't a Debian derivative.