has already mentioned that you need to escape backslashes in a double-quoted string, but you may not realise that
you are using a double-quoted string in your here-doc
your here-doc is being treated as a double-quoted string. Specifically,
my $qqstring = <<"HERE";
This text is subject to double-quoted interpolation. It can include e
+scapes like \t, and $variables.
my $string = <<HERE;
This text is also subject to double-quoted interpolation.
my $qstring = <<'HERE';
This text is treated like a single-quoted string, except that it can c
+ontain embedded single quotes. \t is just a backslash followed by a
+'t', and $variables is just a dollar sign followed by the string 'var