How do I fetch an HTML file?

Use the LWP::Simple module available from CPAN, part of the excellent libwww-perl (LWP) package. On the other hand, and if you have the lynx text-based HTML browser installed on your system, this isn't too bad: 

    $html_code = `lynx -source $url`;
    $text_data = `lynx -dump $url`;