' -A config.system.build.toplevel`), then `result/bin/switch-to-configuration`. That’s all it does.
This bit me before ☹ Unfortunately, `nixos-rebuild` is also responsible for generating the `system` and `system-$n-link` symlinks in `/nix/var/nix/profiles/system`
---
### Author:  [@Lillecarl](https://discourse.nixos.org/u/Lillecarl)
#### Post date: [May 2, 2025, 1:47pm UTC](https://discourse.nixos.org/t/pinning-nixos-with-npins/63721/10 "2025-05-02T13:47:45Z")
Yep @SergeK that’s why there are so many and why there’s no point writing them in Rust or any fancy language. [Here’s a link](https://github.com/Lillecarl/nixos/blob/0cd25a6656976b10b9caf49b4dd637d91b5245f5/users/lillecarl/dotfiles/.config/fish/functions/rebuild-os.fish) to my “nixos-rebuild” reimplemented in fish-shell. Since i don’t support remote building or any other fancy flags it’s really barebones and should make for a good example to build your own with.
The only “magic” is that i pipe the output of nix build through tee to save it to file and process it with “nom” that makes for a nicer rebuild TUI progress experience.
---
### Author:  [@fzakaria](https://discourse.nixos.org/u/fzakaria)
#### Post date: [May 2, 2025, 4:39pm UTC](https://discourse.nixos.org/t/pinning-nixos-with-npins/63721/11 "2025-05-02T16:39:41Z")
Looks like I had already
```auto
# Put nixpkgs into /etc/nixpkgs for convenience
environment.etc.nixpkgs.source = inputs.nixpkgs;
# Point nixpath to that nixpkgs so that the system uses the same nix
nix = {
nixPath = ["nixpkgs=/etc/nixpkgs" "nixos-config=/etc/nixos/configuration.nix"];
```
Not sure if i’m missing more.
---
### Author:  [@piegames](https://discourse.nixos.org/u/piegames)
#### Post date: [May 3, 2025, 7:53am UTC](https://discourse.nixos.org/t/pinning-nixos-with-npins/63721/12 "2025-05-03T07:53:28Z")
This makes me so glad I wrote this post!
Because it took me quite a few iterations to find this solution from first principles, and how I’m hearing from a handful of people that they’ve been doing it like this all along. It really seems to be a useful pattern, and we should document and spread it more. Maybe somewhere in the Wiki as well?
Also no you’re not really missing out on much, the base solution really is only a couple of lines long.
---
### Author:  [@fzakaria](https://discourse.nixos.org/u/fzakaria)
#### Post date: [May 3, 2025, 4:35pm UTC](https://discourse.nixos.org/t/pinning-nixos-with-npins/63721/13 "2025-05-03T16:35:28Z")
Cool.
I can’t remember whose nixOS config I cribbed it from; maybe @Infinisil or jonringer.
Either way – I can attest 100% it’s a good base setting for a starter NixOS project.
(Anything else is “weird” – cause I couldn’t figure out what the nixpath was actually set to.)
---
### Author:  [@TeofilC](https://discourse.nixos.org/u/TeofilC)
#### Post date: [May 6, 2025, 12:23pm UTC](https://discourse.nixos.org/t/pinning-nixos-with-npins/63721/14 "2025-05-06T12:23:39Z")
Great posts! It might be worth mentioning that there is an unexpectedly high performance cost to using `pkgs.path`. It causes the entire nixpkgs source to be refiltered again\[1\]. This can take a few seconds. I work around this by overriding `path` with the actual source of nixpkgs, but any way of passing down the actual source should work.
* * *
1. This happens because the definition of `path` is just a normal path expression like `../.` and nix isn’t smart enough to know that you are just pointing at an already existing storepath, so it does the work of filtering and hashing again.
---
### Author:  [@piegames](https://discourse.nixos.org/u/piegames)
#### Post date: [May 6, 2025, 1:07pm UTC](https://discourse.nixos.org/t/pinning-nixos-with-npins/63721/15 "2025-05-06T13:07:48Z")
Yeah, I’ve run into several other gotchas around using `pkgs.path` naively, however all of my grievances were fixed by using `builtins.storePath pkgs.path` instead.
---
### Author:  [@TeofilC](https://discourse.nixos.org/u/TeofilC)
#### Post date: [May 6, 2025, 1:15pm UTC](https://discourse.nixos.org/t/pinning-nixos-with-npins/63721/16 "2025-05-06T13:15:23Z")
Cool I’ll try that as well!
---
### Author:  [@viperML](https://discourse.nixos.org/u/viperML)
#### Post date: [May 6, 2025, 5:40pm UTC](https://discourse.nixos.org/t/pinning-nixos-with-npins/63721/17 "2025-05-06T17:40:37Z")
For the record, nh v4.0 added support for non-flake installables (I still need to make the annoucement…).
Regular nixos-rebuilds maps to `nh os switch -f ` but you may want to evaluate nixos manually.
---
### Author:  [@fzakaria](https://discourse.nixos.org/u/fzakaria)
#### Post date: [May 28, 2025, 4:20pm UTC](https://discourse.nixos.org/t/pinning-nixos-with-npins/63721/18 "2025-05-28T16:20:38Z")
Here is the home-manager equivalent:
```nix
{
inputs,
outputs,
config,
pkgs,
...
}: {
# keep the source of the nixpkgs we are using easy to find
home.file.".nixpkgs".source = inputs.nixpkgs;
nix = {
package = pkgs.unstable.nixVersions.latest;
nixPath = ["nixpkgs=~/.nixpkgs"];
settings = {
show-trace = true;
experimental-features = ["nix-command" "flakes"];
};
};
}
```
---
### Author:  [@waffle8946](https://discourse.nixos.org/u/waffle8946)
#### Post date: [May 30, 2025, 1:54am UTC](https://discourse.nixos.org/t/pinning-nixos-with-npins/63721/19 "2025-05-30T01:54:26Z")
Isn’t the whole point of the post to _not_ use flakes?
---
### Author:  [@fzakaria](https://discourse.nixos.org/u/fzakaria)
#### Post date: [May 30, 2025, 2:05am UTC](https://discourse.nixos.org/t/pinning-nixos-with-npins/63721/20 "2025-05-30T02:05:25Z")
There was two points AFIR. The other was how to avoid channels on NixOS or make it the same channel you built the system with.
[Next page](https://discourse.nixos.org/t/pinning-nixos-with-npins/63721.md?page=2)