You have the right idea but the wrong specifics. The boundary you're alluding to isn't the kernel/userspace boundary, it's the `libc` boundary, which is admittedly privileged by convention if not by Ring 0.

On most Linux systems this is regrettably `glibc` (in a container where you get to choose everyone chooses the superior option of `musl`), on all Darwin systems this is `libstandard`.

This thread is more concerned with Linux, so you are probably dealing with `/lib64/ld-linux-x86-64.so.2`, which operates in userspace but is by convention and opacity quite clearly part of "the system".

The kernel modification is a much bigger, much weirder side effect of a weird Nix loyalty test around shebang lines in shell scripts, on which is has opted to be intentionally and violently incompatible with everything for no benefit other than incompatibility.

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seanhunter 9 hours ago | parent [-]

That’s a weird rant which is manifestly false. On Nix the benefit you get from the incompatibility is the system can roll forward and back while it’s running so you can do big changes (eg updating or rolling back) the entire system without affecting running processes. You can also run groups of processes in isolation with different sets (or versions) of packages from the rest of the system.

It’s fair to argue about whether those things are really important or whether nix does this in the best way, but to claim that the only benefit is incompatibility is just obvious nonsense.

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reinitctxoffset 7 hours ago | parent [-]

The privileged path is already there. `/usr/bin/env` is no different from `/bin/bash`, `/bin/sh`, or any other ELF artifact at a known place. The argument is made, the argument is spurious. It is made in the other direction regarding the driver run path, just as religious, opposite ruling from purity court. No one even knows why, the trail goes cold in a mysterious 2012 commit about Mesa, it's literally a performance to bring the plane cargo back. Receipts for claim: #141803.

Disagreeing with you doesn't make something a rant. If it's not clear how deep my Nix expertise is I will demonstrate it to any level you like: I'm just as entitled to an opinion as you are and I would appreciate it if the nixpkgs community was a little less rude to anyone who disagrees with some dogma no matter their knowledge. The nixpkgs community is not regarded as healthy or friendly after an internecine faction war that split three ways twice, producing four implementations none of which work, and if that reputation is ever going to mend, it will be because less than every Nix person has precisely zero chill the nanosecond anyone disagrees with them about anything.

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seanhunter 5 hours ago | parent [-]

It's no different other than it's a layer of indirection which allows bash to change in a way that would not be possible if scripts directly referenced /bin/bash or /usr/bin/bash. The only thing you can't change is the /usr/bin/env binary itself but that's not something that changes very much if at all. On my nix box, bash is at /run/current-system/sw/bin/bash and "current-system" is a symlink to a particular build in /nix/store. So /usr/bin/env is creating a layer of indirection so if I rebuild the system, the previous version can be kept around and I can roll back instantly at the boot menu and it will roll everything back to a consistent package set. Now as I say, you could achieve this in other ways eg fs snapshots etc. But to say that the change doesn't give you anything is just very obviously wrong.

And you don't need to worry- it's perfectly obvious how deep your Nix expertise is.

	▲	reinitctxoffset an hour ago \| parent [-]
		You've just used a personal attack to shout down someone who disagrees in good faith over a distinction you simultaneously describe in your own words as "something you could achieve other ways" (yeah, more than a little bit) referencing an artifact that "is a symlink", "on my nix box". The only thing I attacked are named instances of regrettable community malfunctions stripped of anything personal to an individual that hurt both current users of Nix and people who might experiment with systems they can reason about, saw an interaction like this, and did something less painful with their day. Because my evident and sincere concern for the future of Nix is framed as stark disagreement over a few particularly sacred cows. At least on `comp.lang.lisp` you got your middle finger alongside a worthwhile education: "There are some things in life that you do not do if you want to be a moral being and feel proud of what you have accomplished." - Erik Naggum