In a regex, what changes when you add a question mark to .+

Question

I was browsing old php sources and I found a pattern I don\'t understand (probably a copy/past from the internet some times ago ...).

Here is a simple exemple using

Answer 1

+ is a greedy operator; consuming as much as possible. Therefore, .+ will match as much as it can and still allow the remainder of the regular expression to match. Once you specify the question mark +?, you're telling the regex engine (don't be greedy.. as soon as you find a double quote "... stop, you're done.)

Answer 2

The ? makes the match non-greedy, meaning that the expression .+? will match as few characters as possible to make the regex match, rather than matching as any as possible, which is the default behaviour.