A friend of mine gave me a simple file upload program. Here's the file proccessing part:

if ( $q->param() ) {
    my $filehandle = $q->param('file');
    binmode($filehandle);

    open(OUT,">/var/www/html/toiletben/pictures/tempout") || die $!;
    binmode(OUT);

    # process $filehandle
    {
        my $buffer;
        while ( read($filehandle,$buffer,1024) ) {
            print OUT $buffer;
        }
    }

    close(OUT);

    print   $q->header,
            $q->start_html,
            $q->p('File uploaded'),
            $q->end_html;
    exit(0);
}
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Unfortunatly it's mostly uncommented, but I've made sense of most of it. My question is this: I want this script to only accept .jpg files so I need to know how to make this test.

As I understand it, the buffer just recieves a binary stream containing the file itself. How can I test for the file type?