How to escape a forward slash in a regular expression

What context/language? Some languages use / as the pattern delimiter, so yes, you need to escape it, depending on which language/context. You escape it by putting a backward slash in front of it: \/ For some languages (like PHP) you can use other characters as the delimiter and therefore you don't need to escape it. But AFAIK in all languages, the only special significance the / has is it may be the designated pattern delimiter.