Match HTML Comments With Grep and Regex

Question

I have a series of files containing html comments (<!-- some comment -->) that I'm trying to match using grep

Comments span across only 1 line.

Here is my command

grep -rl '<!--.*?-->' ./

This doesn't match. However if I run grep with this regex:

grep -rl '<!--.*?' ./

It works.

The original regex works in javascript, but grep doesn't seem to like it for some reason unknown to me.

Thanks.

Answer 1

The default regex engine (POSIX basic) in grep does not support ?. This works, since . will also match the space:

grep -rl '<!--.*-->' ./