>> I’m also noticing a lack of literature on Perl on the command line, I.e “perl -nae ”.

Searching for 'perl one liners' and the related term 'perl golf' gives many articles and books:

https://www.perl.com/article/perl-one-liners-part-1/

https://www.perl.com/article/perl-one-liners-part-2/

https://catonmat.net/perl-one-liners-explained-part-one

https://catonmat.net/perl-one-liners-explained-part-two

https://catonmat.net/perl-one-liners-explained-part-three

https://catonmat.net/perl-one-liners-explained-part-four

https://catonmat.net/perl-one-liners-explained-part-five

https://catonmat.net/perl-one-liners-explained-part-six

https://catonmat.net/perl-one-liners-explained-part-seven

http://novosial.org/perl/one-liner/

https://www.oreilly.com/library/view/perl-one-liners/9781457...