Jonathan Palardy 'Why Learn AWK' [1]. I'd tried to learn awk a few times but just couldn't grok it. This essay gave me a lightbulb moment.

Honourable mention to 'Automate the Boring Stuff with Python' [2], which does what not a lot of tutorials do - motivate programming for non-technical users.

[1] https://blog.jpalardy.com/posts/why-learn-awk/

[2] https://automatetheboringstuff.com