Sadly only first part is complete. Raku is the much more functionally inspired new Perl. It’s the renaming of Perl 6 and means “camel” or “paradise” in Japanese.

Is Perl/Raku widely used these days? Are they worth learning? I've always been curious about those languages but I've had the impression that people are moving away from them.

Learning Perl is worthwhile because it is ubiquitous on Unix-like systems and Perl-compatible regular expressions are the defacto standard regular expression syntax.

Perl may not be as popular now as it was in the past, but it is still around and lots of legacy systems that were written in Perl are still in active use.

But as Perl-compatible regular expressions are available in many other languages, this is not really a reason for learning Perl itself, right? Or am I missing some deeper insight into regexes, because I don't know Perl?

I find that regular expressions and text-wrangling tasks are faster and easier in Perl than in other programming languages due to its accessible syntax and regular expression engine speed.

This article shows the regular expression syntax in several popular programming languages: https://cs.lmu.edu/~ray/notes/regex/

This GitHub repo gives some regex performance test benchmarks: https://github.com/mariomka/regex-benchmark Perl is pretty fast among the scripting languages that were benchmarked.

If you are familiar with C / C++, then learning Perl is relatively fast and easy: https://perldoc.perl.org/perlintro