I've got a page which does the following... (pseudocode time)

<?php
ob_start();
echo "lots of stuff";
mail(ob_get_contents());
ob_end_clear();
?>

And it all works fine, while it's called through a web browser. But it doesn't bother with the mailing if it gets called by command line, like so...

/usr/bin/php /home/path_to_file/file.php

Any idea why it's not working?