On: Regex character "$" doesn't mean "end-of-string"

[tankenmate]

Not quite, there are standards for this behaviour (formal and de jure).

[danbruc → tankenmate]

And the ones that do not match cat\n with cat$ arguably have it wrong. Both ^ and $ anchor to the start and end of lines, not to the start and end of strings, whether in multi-line mode or not.