I'm curious to understand why this works just fine (as a user)... nix-env -i xev nix-env -i konsole
...but if I put those packages in /etc/nixos/configuration.nix... environment.systemPackages = with pkgs; [ cabal2nix dmenu2 dzen2 gnumake haskellngPackages.xmonad haskellngPackages.xmonad-contrib haskellngPackages.xmonad-extras haskellngPackages.ghc haskellngPackages.cabal-install konsole # causes an error gitAndTools.gitFull meld unison unzip wget xev # causes an error xsel ]; ... I get errors (see below). Is this a bug, or are there some limitations on which packages I can install declaratively? [amy@wombat9000:~/Downloads]$ sudo nixos-rebuild switch building Nix... building the system configuration... error: undefined variable ‘konsole’ at "/etc/nixos/configuration.nix":47:5 (use ‘--show-trace’ to show detailed location information) [amy@wombat9000:~/Downloads]$ sudo nixos-rebuild switch building Nix... building the system configuration... error: undefined variable ‘xev’ at "/etc/nixos/configuration.nix":53:5 (use ‘--show-trace’ to show detailed location information) _______________________________________________ nix-dev mailing list nix-dev@lists.science.uu.nl http://lists.science.uu.nl/mailman/listinfo/nix-dev