FAQ: Difference between revisions
imported>Jtojnar avoid deprecated github:NixOS/nixpkgs-channels |
imported>Symphorien mention overlays to change the version of packages used by nixos modules |
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== How can I install a package from unstable while remaining on the stable channel? == | == How can I install a package from unstable while remaining on the stable channel? == | ||
If you simply want to run a ''nix-shell'' with a package from unstable, you can run a command like the following: | If you simply want to run a ''nix-shell'' with a package from unstable, you can run a command like the following: | ||
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<syntaxhighlight lang="bash">sudo nix-channel --update nixos-unstable</syntaxhighlight> | <syntaxhighlight lang="bash">sudo nix-channel --update nixos-unstable</syntaxhighlight> | ||
queries via <code>nix-env</code> | queries via <code>nix-env</code> will show packages from both ''stable'' and ''unstable''. Use this to install unstable packages into your user environment. The following snippet shows how this can be done in ''configuration.nix''. | ||
<syntaxhighlight lang="nix"> | <syntaxhighlight lang="nix"> | ||
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} | } | ||
</syntaxhighlight> | </syntaxhighlight> | ||
This only changes what version of <code>PACKAGE_NAME</code> is available on <code>$PATH</code>. If the package you want to take from unstable is installed through a NixOS module, you must use [[overlays]]: | |||
<syntaxhighlight lang="nix"> | |||
{ config, pkgs, ... }: | |||
let | |||
unstable = import <nixos-unstable> {}; | |||
in { | |||
nixpkgs.overlays = [ | |||
(self: super: { | |||
PACKAGE_NAME = unstable.PACKAGE_NAME; | |||
}) | |||
]; | |||
} | |||
</syntaxhighlight> | |||
Note that this will rebuild all packages depending on the overlaid package, which may be a lot. Some modules offer a <code>services.foo.package</code> to change the actual derivation used by the module without and overlay, and without recompiling dependencies ([https://nixos.org/manual/nixos/stable/options.html#opt-services.gvfs.package example]). | |||
If you want to install unfree packages from unstable you need to also set allowUnfree by replacing the import statment above with: | If you want to install unfree packages from unstable you need to also set allowUnfree by replacing the import statment above with: | ||