The 2 approaches here are more:

• set a inline section or a POD-like documentation to display as help, or
• properly define a .man file to add to your local man structure

My 2 cents are that unless you really want to blend-in with the system or you have a big multi-files tool: stay to one simple file.

You can still organize at as a chunk of inline-text or properly defined function which sole purpose is to display the help. So no ill done to the poor guy who will maintain your script in 10 years.

The 2 approaches I see here are more:

• setting a inline section or a POD-like documentation to display as help, or
• properly defining a .man file to add to your local man structure

I honestly don't see the point of having a separate file for that kind of help, unless you have a very big tool and the interface/GUI is already in different file(s).

So stay "plain and simple": all in one file regarding your command-line frontend.

You can still organize it as a chunk of inline-text or properly defined function which sole purpose is to display the help. So no ill done to the poor guy who will maintain your script in 10 years.