Generally speaking, a modulino uses the
.pl extension and is included in a library context with a
require (as in,
require '/path/to/my/modulino.pl';). If you already have a bonefide module as
.pm, then you'll necessarily want to create a commandline driver that will
use this module, handle commandline arguments, then do something useful with the functionality encapsulated with the module. You don't want to put the
caller check in file scope of the
.pm then call that
.pm as you would a
.pl script.
So to make your use case consistent with a modulino approach, rename your .pm to .pl; keep the caller based context dispatching and you can call your .pl script a modulino.
But this is sort of going backwards. Like I said above, if you have a .pm file already; just use it in a .pl. The whole point of a modulino really is ephermal; sure they can be long lived, but it's most useful when refactoring legacy code bases into a modular/library centric approach.
Another characteristic of your .pm not being a fully encapsulated module (and maybe inappropriately serving as a modulino) is if you have any commandline argument processing anywhere in it - be it ad hoc, Getopts or what have you. This sort of @ARGV munging typically belongs exclusively inside of a .pl (including one that is a modulino).