Run shell script on boot / start

Question

First of all , my rooted phone is Xiao Mi Red Mi Note 7.

MIUI version : 10.2.3.

Android Version : 9 PKQ1.180904.001.

Shell script :

set -xeo pipefail

_stopnow() {
  test -f stopnow && echo "Stopping!" && rm stopnow && exit 0 || return 0
}

while true

do

    _stopnow

    am instrument -w -r   -e debug false -e class com.package.mobile.name com.package.mobile.test/android.support.test.runner.AndroidJUnitRunner

done

What i have tried :

1. Use SManager Version : 3.0.9

Conclusion of this method : Killed

2. Use service.rc in /system/etc/init

Because i did not have /init.d folder i am using /init instead.

I have file named /system/etc/init/mypackagepipefail.rc and /system/bin/runpipefail

mypackagepipefail.rc

on boot
    start /system/bin/runpipefail
    user system
    group system readproc

runpipefail

#!/bin/sh

set -xeo pipefail

_stopnow() {
  test -f stopnow && echo "Stopping!" && rm stopnow && exit 0 || return 0
}

while true
do
    _stopnow
    # Below here, you put in your command you want to run:
    am instrument -w -r   -e debug false -e class com.airasia.mobile.BigpayTest com.airasia.mobile.test/android.support.test.runner.AndroidJUnitRunner

Conclusion of this method : seems like service does not running on start / boot.

Is there something wrong in usage of the service.rc above ? Is there any other method to run shell script on boot ?

Any help would be so great. Thank you very much.