Is it possible to make a daemon out of a program that reads a file?

Question

linux

There is a program that constantly reads a file and performs actions depending on what was read.
The next question is, is it possible to write a program that will be a demon, and at the same time open a file, read it?

Thank you.

Answer 1

Yes, you can.

Answer 2

Any program can be a daemon if it is configured to start automatically and if its work is in the background, hidden from the user.
Console programs, those that do not work with a graphical shell, can be such without alteration (and the graphical one can also be run in a fake xserver).
The configuration method is different for each version of linux, for example for ubuntu now it is systemd, the first example is from google .