On the off chance that you really use your "potentialy confusing" regex, I will comment that it seems a little inconsistent to me. Can you tell me what it does (including what becomes $1) for each of:
"[ x]", "[ ]", and ""?
Is it what you wanted it to do?
I should also have mentioned that this was a known-fragile regex to parse out some very specific files. The files in question are Matlab files that always have something in the brackets, but not always a leading space. I do have this commented in the actual script, I just didn't add the comment here.