Must i use regex or is there a module to do this kind of operations?
Well, there is never a must to use a regexp. However, the
question is a regexp a good way to tackle this problem
cannot be answered. You don't define how your "tags" look
like, you just give an example. Your example suggests that
tags appear on lines of their own, are all written in full
caps, don't have attributes, don't nest themselves, and
are always of the open/close form (no standalone tags).
Depending on the definition of how tags look like and how
they can appear, regexes may or may not be the way to go.
Abigail