I'm nitpicking I know, but the response header can start and end with many directives...the only absolutely required one is Content-Type (and it must indeed end with two linebreaks). For example, this is perfectly legal:

Set-Cookie: USER_COOKIE=blahblahblah; path=/; domain=.example.com
Content-Type: text/plain
Transfer-Encoding: chunked
Content-Encoding: gzip

This is my content...
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Of course, if the OP is already using CGI (which he should be), then you can simply use the CGI->header() method:

print CGI->header('text/plain');
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