How to limit the launch of a program to one instance?

Question

linux

Task: it is necessary to control that the program is always running and only in one instance.
Usually done through a file next to the process number and checking if it is alive, but maybe there are ready-made popular solutions?

Answer 1

Usually, the file with the process number is created not next to the executable file, but in /var/run/[process name]/[file].pid. This is a simple classic way and you do not need to invent anything.