====== Run a Python programme in the background ======
There are many ways to run a python program as a background service on your raspberry pi at startup. We will use the systemd method.

    * Create a ''.service'' file for your service as below:

<code>sudo nano /lib/systemd/system/helloworld.service</code>

    * Add the below text:

<code>[Unit]
Description=Hello World Service
After=multi-user.target
[Service]
Type=idle
ExecStart=/usr/bin/python /home/pi/helloworld.py
User=pi
[Install]
WantedBy=multi-user.target</code>

 
    * Save and exit the nano editor (by pressing ''Ctrl+X'').
    * The permission on the unit file needs to be set to 644 :

<code>sudo chmod 644 /lib/systemd/system/helloworld.service</code>

    * Reload the system manager configuration by using the following command:


<code>sudo systemctl daemon-reload</code>

    * Start the service using the following command:

<code>sudo systemctl start helloworld.service</code>

    * Stop the service using the following command:

<code>sudo systemctl stop helloworld.service</code>

    * You can enable the service to start at boot as below:

<code>sudo systemctl enable helloworld.service</code>