What's up with the double escaping on the square brackets?

I think this is the solution I'll use - the cleaner as its own file.

Some additional q's... Do I need to escape out smart quotes (singles and doubles) or should I instead specify them some other way? How about forward slash? I'm assuming backward slash just needs a single escape like so \\.

I'd like to convert the slashes to dashes, so I need to account for them, otherwise I wouldn't bother and just leave it to the last sub to drop them.

Damn, there's just a boatload of other characters I want to allow as well.

Can the following be specified plainly (without escaping)... period, comma, colon, semicolon, question mark and the curly brackets { - and how about the shifted characters above the numerals with the exception or asterisk and carat?