mikeraz:
Welcome. Briefly, re your actual question...

 \b marks a word_boundary, not the letter "b" -- except inside a character_class, where it's the metachar for backspace
 /i is a modifier which tells the regex to search in case_INsensitive mode.

The Monastery does some magic with regard to rendering, so read Perl Monks Approved HTML tags. For example, use &#91; to write an open_square_bracket here; a literal bracket, except inside <code>... </code> or <c>... </c> tags operates in the Monastery's specialized parsing as a link token.

In short, you need to read how to post here, starting with Welcome to the Monastery and How do I post a question effectively?-- but even before that, you should probably read perlretut and similar regex introductions (including Tutorials#regexdata) as your question suggests you've missed some very basic info.