In this section, we're going to look at ways we can modify systemd unit files.
There's an important note to make here, which is that, while you can absolutely modify configuration files as they're delivered, there's no guarantee that your changes will be persistent across updates of your system. Package managers might take offence to your mangling of their service files, and simply replace them without warning.
The correct way to modify the actions of systemd unit files is to write a whole other file with your changes included.
systemd's method for doing this is called a snippet.
