#!/bin/bash
# ========================================================
# Bash script for operation hours counter
# Version 1.0 - by Thomas Schoch - www.retas.de
# ========================================================

# File runtime has format: "00:00 0" (time HH:MM and min).
# The script is called every minute by cron and increments
# the above values.

file=/home/pi/sys/runtime
read HHMM min <$file
(( min += 1 ))
(( HH = min / 60 ))
(( MM = min - HH * 60 ))
printf "%02d:%02d $min\n" $HH $MM >$file