How to update a Github Pages Jekyll blog after years of inactivity

Check out this docs page.

It’s been two years. You don’t even remember how to run this locally, don’t you?

bundle exec jekyll serve

Ah, but if you’re running a ruby version > 3.1.2 then you’re screwed. Switch to 3.1.2 (using your beloved chruby). At least according to this issue comment.