Check if the system dpkg need a restart and send corresponding signal, as a service

auto-reboot.sh

#!/bin/bash
# auto-reboot
# description: Check if the system dpkg need a restart and send corresponding signal

start() {
    # code to start app comes here 
    # example: bahs -c "program_name" &
    bash -c "while [ ! -f /var/run/reboot-required ]; do sleep 30; done; cat /var/run/reboot-required.dpkgs 2> /dev/null; reboot" &
    echo $! > /var/run/chkdpkgs.pid
}

stop() {
    # code to stop app comes here 
    # example: kill program_name.pid
    kill $(cat /var/run/chkdpkgs.pid) 
    rm /var/run/chkdpkgs.pid
}

status() {
   if [ -e /var/run/chkdpkgs.pid ]; then
      echo auto-reboot is running, pid=$(cat /var/run/chkdpkgs.pid)
   else
      echo auto-reboot is NOT running
      exit 1
   fi
}
case "$1" in 
    start)
       start
       ;;
    stop)
       stop
       ;;
    restart)
       stop
       start
       ;;
    status)
       # code to check status of app comes here 
       # example: status program_name
       status 
      ;;
    *)
       echo "Usage: $0 {start|stop|status|restart}"
esac

exit 0 

/etc/systemd/system/auto-reboot.service
`[Unit]
Description=Auto-Check system reboot-required status and reboot

[Service]
Type=forking
ExecStart=/usr/local/bin/auto-reboot.sh start
ExecStop=/usr/local/bin/auto-reboot.sh stop
PIDFile=/var/run/chkdpkgs.pid

[Install]
WantedBy=multi-user.target
`

sudo systemctl enable auto-reboot

The system should reboot at anytime if the message **** System reboot is required **** is displayed on login shell.