use Data::Dumper   qw( Dumper );
use HTML::Entities qw( encode_entities );

open(FILE, '<', 'file.txt');
binmode(FILE);
my $content; { local $/; $content = <FILE>; }
close(FILE);

print "Content-Type: text/html; encoding=utf-8\n\n";

local $Data::Dumper::Useqq = 1;
print '<pre>';
print encode_entities(Dumper($content));
print '</pre>';
print $content;