For awk, start with the book by Kernighan/Aho/Weinberger. The PDF of the first edition is freely available on archive.org, and a second edition has been announced. Chapter 2 of the first edition is only 40 pages, and describes all language features.

https://news.ycombinator.com/item?id=13451454

For sed, the best resource is likely the free "UNIX Bookshelf" from O'Reilly that can be found online; this contains a book specifically focusing on Sed and Awk.

https://freecomputerbooks.com/The-Unix-CD-Bookshelf-Version-...

I've shared this before, but this sed tutorial made me a pro. [0] Even if you don't use it for more complex things, you may find there are faster ways to do the things you are now.

[0]: https://www.grymoire.com/Unix/Sed.html

Edit: That said, I don't even want to start dissecting the submitted code.

I have ebooks on GNU sed and GNU awk with plenty of examples and exercises (free to read online):

* https://learnbyexample.github.io/learn_gnused/

* https://learnbyexample.github.io/learn_gnuawk/

I also wrote TUI apps for interactive exercises (grep, sed, awk, etc): https://github.com/learnbyexample/TUI-apps

Just use Perl for one-liners. It's more powerful than sed/awk but it does pretty much everything those do.

This taught me awk, from an HN submission years ago: https://ferd.ca/awk-in-20-minutes.html

I've had some fun using awk to generate C# classes for an Ultima Online emulator.

awk can do much more than sed. And, with patience, you could even write a Z-machine interpreter on it as some guy did with postscript. You might have to convert the binary input to hex first with xxd/od in order to parse the opcodes in a nice way, but everything else would be simulated from awk.