system: "x86_64-linux", multi-user?: yes, version: nix-env (Nix) 2.1.3, channels(rokka): "nixpkgs-19.03pre151875.7c1b85cf6de", channels(root): "nixos-19.03pre155123.32bcd72bf28, nixpkgs-19.03pre154774.cefd0f7e86b", nixpkgs: /home/rokka/.nix-defexpr/channels/nixpkgs