Applications and scripts can be stopped and started automatically in the guest shell environment using systemd.

The below script named /home/guestshell/datecap.sh will save a file in the /tmp named datecap:

#!/bin/bash

OUTPUTFILE=/tmp/datecap

rm -f $OUTPUTFILE
while true
do
    echo $(date) >> $OUTPUTFILE
    echo 'Hello World' >> $OUTPUTFILE
    sleep 10
done

This script can be tied into the systemd infrastructure with the following file named /usr/lib/systemd/system/datecap.service:

[Unit]
Description=Trivial "datecap" example daemon

[Service]
ExecStart=/home/guestshell/datecap.sh &
Restart=always
RestartSec=10s

[Install]
WantedBy=multi-user.target  

After creating the two files, the user can use systemctl to start and stop the datecap process:

[guestshell@guestshell tmp]sudo systemctl start datecap

[guestshell@guestshell tmp]$ sudo systemctl status -l datecap
datecap.service - Trivial "datecap" example daemon
    Loaded: loaded (/usr/lib/systemd/system/datecap.service; disabled)
    Active: active (running) since Wed 2015-09-30 02:52:00 UTC; 2min 28s ago
Main PID: 131 (datecap.sh)
    CGroup: /system.slice/datecap.service
        ??131 /bin/bash /home/guestshell/datecap.sh &
        ??164 sleep 10

Sep 30 02:52:00 guestshell systemd[1]: Started Trivial "datecap" example daemon.


[guestshell@guestshell tmp]$ sudo systemctl stop datecap

When the device is rebooted, systemd will automatically start the datecap daemon.