How to programmatically determine the path to the folder where the service starts from in Linux?

Question

linux

On Debian, I can read a file in /etc/systemd/system/ and take the path from the ExecStart parameter. Perhaps there are other ways?

There are also Linux distributions without systemd and I would like to understand how to get this information there. Where and how is it stored?

Answer 1

/etc/init.d/ contains sysV init scripts.
And the full path to the binary of any running process can be checked, knowing the PID:
ls -la /proc/PID/exe