Write a CGI script that:

• Opens the required file.
• Reads the file and writes the contents to STDOUT

Don't forget to write the correct Content-type header.

"The first rule of Perl club is you don't talk about Perl club."

Yes as davorg suggests just dumping the file to STDOUT from the script is enough.

Beware of the security implications though.
Make sure your script will not open just any file it is asked to.
You don't want some kid typing: www.myserver.org/myscript.pl?file=../../../etc/passwd or some such thing !!!

# First set up a few values for the download header
my ($sec, $min, $hr, $day, $mon, $yr, $wday) = (gmtime());
$sec  = sprintf("%2.2d",  $sec     );
$min  = sprintf("%2.2d",  $min     );
$hr   = sprintf("%2.2d",  $hr      );
$day  = sprintf("%2.2d",  $day     );
$yr   = sprintf("%4.4d", ($yr+1900));
$mon  = ('Jan','Feb','Mar','Apr','May','Jun',
         'Jul','Aug','Sep','Oct','Nov','Dec')[$mon];
$wday = ('Sun','Mon','Tue','Wed','Thu','Fri','Sat')[$wday];
my $server = $ENV{SERVER_SOFTWARE};
$server =~ s/^(\S+)//;
#
#. . . omitted some code here
#
# Now do the download
open DOWNLOAD, "<$upload_dir/$dir/$filename" 
   or die "Can't open $upload_dir/$dir/$filename\n";

my ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,
    $size,$atime,$mtime,$ctime,$blksize,$blocks) = stat DOWNLOAD;
print "Date: $wday, $day $mon $yr $hr:$min:$sec GMT\n";
print "Server: $server\n";
print "MIME-version: 1.0\n";
print "Content-type: $content_type\n";
print "Content-length: $size\n";
print "\n";

binmode STDOUT;
while (read(DOWNLOAD, $buffer, $buffer_size)) {
   print $buffer;
}
close DOWNLOAD;
[download]

Hope this helpes.