# installation of service systemd fedora
# service systemctl systemd fedora

cat << ENDOS > /usr/local/bin/test
#!/bin/bash
date > /var/log/test.log
while true
do
  date  >> /var/log/test.log
  sleep 120
done
ENDOS

chmod  u+x /usr/local/bin/test

cat << ENDOS > /lib/systemd/system/test.service
[unit]
Description=It is just a test
After=syslog.target network.target 
[Service]
Type=simple
ExecStart=/usr/local/bin/test
[Install]
WantedBy=multi-user.target
ENDOS

systemctl daemon-reload
systemctl start test service

# eventually
# systemctl enable test.service