How can line breaks affect the functionality of regular expressions in PHP?

Line breaks can affect regular expressions in PHP when using the dot (.) metacharacter, which matches any character except a newline. If your regular expression includes the dot metacharacter and you want it to match newline characters as well, you can use the "s" modifier at the end of the regular expression pattern. This modifier changes the behavior of the dot metacharacter to match any character, including newline characters.

$pattern = '/example.regex/s';