in reply to Regex question is this one of those look (ahead|behind)s ?

(note SB = SQUARE BRACKET, this EDITOR is removing them for some reason)

That's because you're not using  <code> ... </code> tags! Please use code tags! (Can also be abbreviated  <c> ... </c>) Please see How do I post a question effectively?, Writeup Formatting Tips and Markup in the Monastery.