Nix
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How to Learn Nix, Part 49: nix-direnv is a huge quality of life improvement
The reason I discovered an ancient blog post the other day was that I had something new to say about Nix for the first time in over two years. The thing I want to say is this: nix-direnv is great. It fixes roughly every problem that I’ve had with nix-shell, and does so in a much nicer way than my previous ad-hoc solutions.
Multiple Rails development environments using nix-shell
Four Rails apps using different versions of Ruby, Rails, PostgreSQL and MySQL