I'm writing a test to check whether a tool I'm writing can work without Nix (it works with it perfectly, but I want it to also work without it because there are a lot of folks like you, and like me about 3 years ago, who still think they'd rather struggle with manually installing the right glibc that goes with the right python dependency installed with the right pip and venv versions, to the right location, that goes with the right python version that makes Whisper models work (literally the thing I'm currently working on), instead of just running `nix develop` and getting a coffee and then done.
And all I have to do to simulate "no Nix" is to remove all the nix paths from PATH (I suppose I could purge it from the linker paths as well, now that I think about it). But that's it.
What Nix does is put its entire repo into a separate part of your hard drive owned by root, and create a few build users for security reasons. That's (to me) not particularly "invasive," but YMMV (and if you use the Determinate Nix installer, it's even more trivial to uninstall than the official way). Also, when you run `nix develop`, the environment changes it does to make everything "just work" (like PATH changes etc) are only valid for that terminal session. Again, this is the least intrusive thing possible while also providing the guarantees it does, and is also (more or less) guaranteed to work.
The Nix whitepaper is pretty readable and not that long. I recommend it to understand why it's important and useful: https://edolstra.github.io/pubs/nspfssd-lisa2004-final.pdf
There is also Guix, which is like Nix but uses Guile (a Scheme dialect) as its scripting language all the way down to the bare metal (literally, the boot loader is written in it, I believe, as soon as the interpreter is loaded somehow). Their strategy seems to be to let Nix take the lead and make all the mistakes and then implement the way that seems to work the best, in its own ecosystem/tooling: https://guix.gnu.org/ But they have a lot fewer packages than Nix does.
Both of these let you define an entire machine with a single configuration file that is far more guaranteed to work than running a Dockerfile.
