I am trying to grab the capital letters of a couple of words and wrap them in span tags. I am using preg_replace for extract and wrapping purposes, but it's not outputting anything.

preg_replace("/[A-Z]/", "<span class=\"initial\">$1</span>", $str)

 Put the match in parentheses, like this:

preg_replace("/([A-Z])/", "<span class=\"initial\">$1</span>", $str)