Windows line breaks are LF (\r) followed by a CR (\n), so to match a line break in windows use the regular expression \r\n.
If you have a line break, $ will match before the line break, and ^ after it.
You can match a CR (\r) not followed by LF (\n) with \r(?!\n).
UNIX uses an LF character only.
Apple uses a CR character only.