You can find similar examples with just \n in the official Apache docs on CGI: https://httpd.apache.org/docs/2.4/howto/cgi.html https://httpd.apache.org/docs/2.

You can find similar examples with just \n in the official Apache docs on CGI: https://httpd.apache.org/docs/2.4/howto/cgi.html https://httpd.apache.org/docs/2.4/howto/cgi.html The solution for this puzzle is that mod_cgi will simply convert LF to CRLF silently. (more precisely: it parses the headers the script outputs in a relaxed way and lets the server write them in a correct format later)