Have your CGI script return a content type of "text/plain". You don't need to do any formatting whatsoever.

Code is as follows:

  print "Content-type: text/plain\n\n";
 
  # print text file here
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Or if you're using CGI.pm...

  my $q = CGI->new();

  # handle any CGI parameters, set other headers, etc.

  print $q->header( { -type=>'text/plain' } );

  # print text file here
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