Ask HN: Beautiful shell code?

What are some examples of beautiful shell code?

Bash---and, in general, shell---gets a lot of flack for being a bad programming language. I understand the sentiment, but after writing a few klocs, with copious support from shellcheck[0], that feeling changed for me. I think bash, and even POSIX shell, can be reasonable languages, well-suited to certain problems.

Without providing rigid metrics, I'm curious about scripts HN has encountered (or produced!) that you consider high-quality.

[0]:https://github.com/koalaman/shellcheck