I suspect you're being distracted by having too much information thrown at you at once.

Examine just this bit of your code:

my @list_files;

for my $filename (@list_files)
{
}
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Do you see the problem? You just declared @list_files, so by definition it has nothing in it.

Your loop therefore has nothing to do.

Perhaps this will help you see the path forward:

my @list_files = readdir $dir;
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