Run a Program On Your Raspberry Pi At Startup
The method that I usually use to run a program on your Raspberry Pi at startup is to use the file rc.local. In order to have a command or program run when the Pi boots, you can add commands to the rc.local file. This is especially useful if you want to power up your Pi in headless mode (that is without a connected monitor), and have it run a program without configuration or a manual start.
Editing rc.local
On your Pi, edit the file /etc/rc.local using the editor of your choice. You must edit it with root permissions:
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sudo nano /etc/rc.local |
Add commands to execute the python program, preferably using absolute referencing of the file location (complete file path are preferred). Be sure to leave the line exit 0 at the end, then save the file and exit. In nano, to exit, type Ctrl-x, and then Y.
If your program runs continuously (runs an infinite loop) or is likely not to exit, you must be sure to fork the process by adding an ampersand (“&”) to the end of the command, like:
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sudo python /home/pi/sample.py & |
The Pi will run this program at bootup, and before other services are started. If you don’t include the ampersand and if your program runs continuously, the Pi will not complete its boot process. The ampersand allows the command to run in a separate process and continue booting with the main process running.
Now reboot the Pi to test it:
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sudo reboot |
Hints
Also, be sure to reference absolute file names rather than relative to your home folder. For example use /home/pi/myscript.py instead of myscript.py.
If you add a script into /etc/rc.local, it is added to the boot sequence. If your code gets stuck then the boot sequence cannot proceed. So be careful as to which code you are trying to run at boot and test the code a couple of times. You can also get the script’s output and error written to a text file (say log.txt) and use it to debug.
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sudo python /home/pi/sample.py & > /home/pi/Desktop/log.txt 2>1 |
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