https://forums.pimoroni.com/t/unicorn-hat-python-script-stops-after-8-hours/6275/12
Although probably what you really want is a systemd unit to start up your Python script. Something like:
[Unit]
Description=My Python Service
After=multiuser.target
Requires=local-fs.target
[Service]
Restart=always
Type=simple
ExecStart=/usr/bin/python /home/pi/Pimoroni/unicornhathd/examples/candle.py
[Install]
WantedBy=default.target
Save this as a file by running: sudo nano /etc/systemd/system/mypython.service and pasting in the above.
Then reload systemd:
sudo systemctl daemon-reload
And start your new service:
sudo systemctl start mypython
You can also get its status:
sudo systemctl status mypython
And stop it:
sudo systemctl stop mypython
And enable it to auto-start on boot:
sudo systemctl enable mypython