It can depend upon a couple of things. May moons ago I tried to get buffering to work properly under Apache. I could never get it to go. Then, at one point we upgraded to newer version of Apache, and suddenly the buffering began to work just as you wanted above. I think the version change was right around the move from a 1.2 Apache to a 1.3 something Apache. All new versions of Apache seem to work fine.

Newer versions of Apache will do the buffering correctly, but they will do it different from the command line. On the command line, any character sent shows up. In Apache, you need to send it a newline before the buffer is flushed. However, even if the buffer is flushed, that doesn't mean it will show up. If you look at your browser's status, you will see the size of the document get bigger. Sending a newline to the browser is not enough for it to show output. What you will need to do to make a line of text to show up is to include a <br> or <p> or something that will signal the end of a line so that the browser is then able to render it. So make sure each of your lines is properly terminated with a <br>\n and all will be well with your buffering.