mjhjmtu

I have written a small bash script (datalogger.sh) to store the mqtt data on to SD card inside a linux machine. The bash script is as below:-

#!/bin/bash
fileNumber=1
temp=1 // flag to check and create new files
fileName="Data"
while [ $temp -le 1 ]
do
 if [ -f "/media/card/$fileName$fileNumber.txt" ]
 then
 ((fileNumber++))
 else
 touch "/media/card/$fileName$fileNumber.txt"
 mosquitto_sub -v -t "gateway/+/rx" | tee /media/card/$fileName$fileNumber.txt
 temp=2
 fi
done

The bash script works totally fine if i run it with the following command

./datalogger.sh

As of next step, i used the update-rc.d datalogger.sh defaults so that on boot the bash script automatically runs. However, i only get the empty text files. Could anyone guide me, what mistake i am making?
Best Regards,

Services generaly use wrapper scripts like for example;

#!/bin/bash

# Provides: example
# Required-Start:
# Should-Start:
# Required-Stop:
# Default-Start: 2 3 5
# Default-Stop: 0 1 2 6
# Short-Description: example
# Description: example

#
# /etc/init.d/example
#

set -e
trap 'echo "ERROR: $BASH_SOURCE:$LINENO $BASH_COMMAND" >&2' ERR

NPID=$(pgrep -f example2.sh || true);

function start 
 if [ "$NPID" = "" ] ; then
 screen -S example -d -m bash -c '/root/example2.sh'
 else
 echo "example service is already running as $NPID";
 fi


function stop 
 if [ "$NPID" != "" ] ; then
 kill "$NPID";
 else
 echo "example service was not running" >&2;
 fi


function status 
 if [ "$NPID" = "" ]; then
 echo "example is not running";
 else
 echo "example is running with pid $NPID";
 fi


if [ "$1" = "start" ]; then
 start
elif [ "$1" = "stop" ]; then
 stop
elif [ "$1" = "restart" ]; then
 stop;
 start;
elif [ "$1" = "status" ]; then
 status
else
 echo " * Usage: /etc/init.d/example start";
fi