It's not wrong actually. It's the difference between BRE and ERE, which are the two different POSIX standards that define regex. In BRE the $ should always matc

It's not wrong actually. It's the difference between BRE and ERE, which are the two different POSIX standards that define regex. In BRE the $ should always match the end of the string (the spec specifically says it should match the string terminator since "newlines aren't special characters"), while the ERE spec says it should match until the end of the line. The real issue is that no language nowadays "just" implements BRE or ERE since both specs are lacking in features. Most languages instead implement some variant of Perl's regex instead (often called PCRE regex because of the C library that brought Perl's regex to C), which as far as I can tell isn't standardized, so you get these subtle differences between implementations.