#!/bin/bash

echo "4" > /sys/class/gpio/export
echo "in" > /sys/class/gpio/gpio4/direction

previous=$(cat /sys/class/gpio/gpio4/value)

while true
do
  pin=$(cat /sys/class/gpio/gpio4/value)

  if [ $pin -gt $previous ]
  then
    echo "Hier das Programm starten"
  else
    sleep 0.5
  fi

  previous=$pin
done