Just as a sidenote, this

my $whole_file;
{
   local($/) = undef;
   $whole_file = <F>;  # <> operator reads in all of the data from fil
+ehandle F
}
[download]

could also be written more concisely like this:

my $whole_file = do { local $/; <F> };
[download]

-- Hofmator