mirror of https://github.com/NixOS/nix.dev.git synced 2024-10-18 14:32:43 -04:00

Valentin Gagarin cfa14f780a

* update the FAQ on packaging

Co-authored-by: Silvan Mosberger <github@infinisil.com>

2024-01-29 01:41:51 +00:00

4.6 KiB

Raw Blame History

Frequently Asked Questions

Nix

How do I add a new binary cache?

Using NixOS (≥ 22.05):

nix.settings = {
  trusted-substituters = [ "https://cache.nixos.org" ];
  substituters = [ "https://cache.nixos.org" ];
};

Using NixOS (≤ 21.11):

nix = {
  trustedBinaryCaches = [ "https://cache.nixos.org" ];
  binaryCaches = [ "https://cache.nixos.org" ];
};

Using Nix:

$ echo "trusted-binary-caches = https://cache.nixos.org" >> /etc/nix/nix.conf
$ nix-build helpers/bench.nix --option extra-binary-caches https://cache.nixos.org

How to operate between Nix paths and strings?

See http://stackoverflow.com/a/43850372

How to build reverse dependencies of a package?

$ nix-shell -p nixpkgs-review --run "nixpkgs-review wip"

How can I manage dotfiles in $HOME with Nix?

See https://github.com/nix-community/home-manager

What's the recommended process for building custom packages?

Please read .

How to use a clone of the Nixpkgs repository to update or write new packages?

Please read and the Nixpkgs contributing guide.

NixOS

How to run non-nix executables?

NixOS cannot run dynamically linked executables intended for generic Linux environments out of the box. This is because, by design, it does not have a global library path, nor does it follow the Filesystem Hierarchy Standard (FHS).

There are a few ways to resolve this mismatch in environment expectations:

Use the version packaged in Nixpkgs, if there is one. You can search available packages at https://search.nixos.org/packages.
Write a Nix expression for the program to package it in your own configuration.

There are multiple approaches to this:
- Build from source.
  
  Many open-source programs are highly flexible at compile time in terms of where their files go. For an introduction to this, see .
- Modify the program's ELF header to include paths to libraries using autoPatchelfHook.
  
  Do this if building from source isn't feasible.
- Wrap the program to run in an FHS-like environment using buildFHSEnv.
  
  This is a last resort, but sometimes necessary, for example if the program downloads and runs other executables.
Create a library path that only applies to unpackaged programs by using nix-ld. Add this to your configuration.nix:
```
  programs.nix-ld.enable = true;
  programs.nix-ld.libraries = with pkgs; [
    # Add any missing dynamic libraries for unpackaged programs
    # here, NOT in environment.systemPackages
  ];
```
Then run nixos-rebuild switch, and log out and back in again to propagate the new environment variables. (This is only necessary when enabling nix-ld; changes in included libraries take effect immediately on rebuild.)

:::{note} nix-ld does not work for 32-bit executables on x86_64 machines. :::
Run your program in the FHS-like environment made for the Steam package using steam-run:
```
$ nix-shell -p steam-run --run "steam-run <command>"
```

How to build my own ISO?

See http://nixos.org/nixos/manual/index.html#sec-building-image

How do I connect to any of the machines in NixOS tests?

Apply following patch:

diff --git a/nixos/lib/test-driver/test-driver.pl b/nixos/lib/test-driver/test-driver.pl
index 8ad0d67..838fbdd 100644
--- a/nixos/lib/test-driver/test-driver.pl
+++ b/nixos/lib/test-driver/test-driver.pl
@@ -34,7 +34,7 @@ foreach my $vlan (split / /, $ENV{VLANS} || "") {
     if ($pid == 0) {
         dup2(fileno($pty->slave), 0);
         dup2(fileno($stdoutW), 1);
-        exec "vde_switch -s $socket" or _exit(1);
+        exec "vde_switch -tap tap0 -s $socket" or _exit(1);
     }
     close $stdoutW;
     print $pty "version\n";

And then the vde_switch network should be accessible locally.

How to bootstrap NixOS inside an existing Linux installation?

There are a couple of tools:

4.6 KiB Raw Blame History