Almost

    
use strict;
use warnings;

MAIN: {
    open my $fh,">","filename";
    ... 
    nose();
    ...
}

sub nose {...;}
[download]

nose() won't have access to any lexical vars defined inside the main block.

> I can’t tell how often I’ve been blamed for it.

It's a variation of putting the main code into a main() sub and calling it from the start.

I think it's a pattern taken from C and I've seen some monks here advocating it.