Welcome to the Monastery. In the future, please wrap input in <code> tags so it doesn't get mangled. Note how chunks of your post got linkified.
The basics of your question are documented in Extracting matches in perlretut. The only trick, assuming you mean to be using [ and ] as delimiters, is that these characters have special meaning in regular expressions, and thus must be escaped. Your regular expression might look something like /\[(.*?)\]/.
#11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.