nix-env isn't meaningfully an escape hatch, since you can still only use it with stuff that's packaged in Nix's peculiar way. Here's an overview of the escape

nix-env isn't meaningfully an escape hatch, since you can still only use it with stuff that's packaged in Nix's peculiar way. Here's an overview of the escape hatches that are currently around in NixOS for package management, meaning you can use them to avoid packaging something natively for Nix, or to run pre-built software for other distros or targeting multiple distros: • flatpak — use flatpak to install stuff just like you would on any other distro: https://nixos.org/manual/nixos/stable/index.html#module-services-flatpak https://nixos.org/manual/nixos/stable/index.html#module-serv... • FHS user environments — create a usermode chroot that puts Nix packages where naive `./configure; make; make install` programs will expect to see their dependencies • steam-run — run whatever in the pre-built FHSUserEnv that Nixpkgs uses for Steam: https://nixos.org/manual/nixpkgs/stable/#sec-steam-run https://nixos.org/manual/nixpkgs/stable/#sec-steam-run • AppImage — launch an AppImage using `appimage-run` or create a quick and dirty Nix package that wrapps an existing AppImage: https://nixos.org/manual/nixpkgs/stable/#sec-pkgs-appimageTools https://nixos.org/manual/nixpkgs/stable/#sec-pkgs-appimageTo... • Docker — you can run stuff with Docker if ya want: https://search.nixos.org/options?channel=unstable&show=virtualisation.docker.enable&from=0&size=50&sort=relevance&query=docker.enable https://search.nixos.org/options?channel=unstable&show=virtu... NixOS also includes little escape hatches on the configuration side for every service. Basically every module also has an ‘extraConfig’ type of option, which lets you append to the config file that NixOS generates for the service in its original/raw format. Otherwise, you're generally looking at setting up a chroot environment. I can think of some ways that NixOS could be a little more generous with escape hatches, but I don't think there's much developer interest in the community.