Asyncronous Cron Jobs on Linux

Cron jobs are nice, but what about when your machine is off? Perhaps you want to run a task daily/weekly/monthly and run it right away after you boot if it is due. We can do this with anacron.

On Arch Linux install the cronie package:

yay -S cronie

In this example I'll use a Python script update.py, but you could use a shell/bash script instead.

Check your active Python environment:

which python3

/path/to/your/python/env/bin/python3

Edit update.py

vi /path/to/your/python/script/update.py

Put this at the top of the file:

#!/path/to/your/python/env/bin/python3

Make your python script executable:

chmod +x /path/to/your/python/script/update.py

I want to run this update script daily so I shall make a symbolic link in /etc/cron.daily:

sudo ln -s /path/to/your/python/script/update.py /etc/cron.daily/update

That's it, my machine will now update once daily and will update if it is due after booting.