This option provides access to the overridden result of programs.singularity.package. For example, the following configuration makes all the Nixpkgs packages use the overridden singularity: { config, lib, pkgs, ... }: { nixpkgs.overlays = [ (final: prev: { _singularity-orig = prev.singularity; singularity = config.programs.singularity.packageOverriden; }) ]; programs.singularity.enable = true; programs.singularity.package = pkgs._singularity-orig; } Use lib.mkForce to forcefully specify the overridden package.

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