diff --git a/default.nix b/default.nix
index 6cffc27a..ae5156ec 100644
--- a/default.nix
+++ b/default.nix
@@ -12,14 +12,20 @@ let
         ./modules/system/defaults
         ./modules/system/etc.nix
         ./modules/system/launchd.nix
+        ./modules/nix
         ./modules/environment
         ./modules/launchd
         ./modules/services/activate-system.nix
         ./modules/services/nix-daemon.nix
         ./modules/programs/tmux.nix
-        ./modules/programs/nix-darwin.nix
       ];
   };
 
+  system = eval.config.system.build.toplevel;
+
 in
-  eval
+
+{
+  inherit (eval) config;
+  inherit system;
+}
diff --git a/modules/examples/lnl.nix b/modules/examples/lnl.nix
index 3db37bfd..9ddd4268 100644
--- a/modules/examples/lnl.nix
+++ b/modules/examples/lnl.nix
@@ -1,242 +1,153 @@
-{ pkgs ? import <nixpkgs> {} }:
-
-let
-
-  config =
-    { config, lib, pkgs, ... }:
-    {
-      environment.systemPackages =
-        [ pkgs.lnl.zsh
-          pkgs.lnl.tmux
-          pkgs.lnl.vim
-          pkgs.curl
-          pkgs.fzf
-          pkgs.gettext
-          pkgs.git
-          pkgs.jq
-          pkgs.silver-searcher
-
-          pkgs.nix-repl
-          pkgs.nox
-        ];
-
-      services.nix-daemon.enable = true;
-      services.nix-daemon.tempDir = "/nix/tmp";
-
-      services.activate-system.enable = true;
-
-      system.defaults.global.InitialKeyRepeat = 10;
-      system.defaults.global.KeyRepeat = 1;
-
-      programs.tmux.loginShell = "${pkgs.lnl.zsh}/bin/zsh -l";
-      programs.tmux.enableSensible = true;
-      programs.tmux.enableMouse = true;
-      programs.tmux.enableFzf = true;
-      programs.tmux.enableVim = true;
-
-      programs.tmux.tmuxConfig = ''
-        bind 0 set status
-
-        set -g status-bg black
-        set -g status-fg white
-      '';
-
-      environment.variables.EDITOR = "vim";
-      environment.variables.HOMEBREW_CASK_OPTS = "--appdir=/Applications/cask";
-
-      environment.variables.SHELL = "${pkgs.lnl.zsh}/bin/zsh";
-
-      environment.variables.GIT_SSL_CAINFO = "${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt";
-      environment.variables.SSL_CERT_FILE = "${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt";
-
-      environment.shellAliases.l = "ls -lh";
-      environment.shellAliases.ls = "ls -G";
-      environment.shellAliases.g = "git log  --oneline --max-count 42";
-      environment.shellAliases.gl = "git log --graph --oneline";
-      environment.shellAliases.gd = "git diff --minimal --patch";
-
-      environment.etc."zprofile".text = ''
-        # /etc/zprofile: DO NOT EDIT -- this file has been generated automatically.
-        # This file is read for login shells.
-
-        # Only execute this file once per shell.
-        if [ -n "$__ETC_ZPROFILE_SOURCED" ]; then return; fi
-        __ETC_ZPROFILE_SOURCED=1
-
-        autoload -U promptinit && promptinit
-        PROMPT='%B%(?..%? )%b⇒ '
-        RPROMPT='%F{green}%~%f'
-
-        bindkey -e
-        setopt autocd
-
-        autoload -U compinit && compinit
-
-        nix () {
-          cmd=$1
-          shift
-
-          case $cmd in
-            'b'|'build')        nix-build --no-out-link -E "with import <nixpkgs> {}; $@" ;;
-            'e'|'eval')         nix-instantiate --eval -E "with import  <nixpkgs> {}; $@" ;;
-            'i'|'instantiate')  nix-instantiate -E "with import <nixpkgs> {}; $@" ;;
-            'r'|'repl')         nix-repl '<nixpkgs>' ;;
-            's'|'shell')        nix-shell -E "with import <nixpkgs> {}; $@" ;;
-            'p'|'package')      nix-shell '<nixpkgs>' -p "with import <nixpkgs> {}; $@" --run ${pkgs.lnl.zsh}/bin/zsh ;;
-            'z'|'zsh')          nix-shell '<nixpkgs>' -E "with import <nixpkgs> {}; $@" --run ${pkgs.lnl.zsh}/bin/zsh ;;
-          esac
-        }
-
-        nixdarwin-rebuild () {
-          cmd=$1
-          shift
-
-          case $cmd in
-            'build')   nix-build '<nixpkgs>' -A nixdarwin.toplevel "$@" ;;
-            'repl')    nix-repl "$HOME/.nixpkgs/config.nix" "$@" ;;
-            'shell')   nix-shell '<nixpkgs>' -p nixdarwin.toplevel --run ${pkgs.lnl.zsh}/bin/zsh "$@" ;;
-            'exec')    __ETC_ZSHRC_SOURCED= __ETC_ZSHENV_SOURCED= __ETC_ZPROFILE_SOURCED= exec ${pkgs.lnl.zsh}/bin/zsh -l ;;
-            'switch')  systemConfig=$(nix-build --no-out-link '<nixpkgs>' -A nixdarwin.toplevel) && nix-shell '<nixpkgs>' -A nixdarwin.toplevel --run 'sudo $out/activate' && sudo nix-env --profile ${config.system.profile} --set $systemConfig ;;
-          esac
-        }
-
-        conf=$HOME/src/nixpkgs-config
-        pkgs=$HOME/.nix-defexpr/nixpkgs
-
-        # Read system-wide modifications.
-        if test -f /etc/zprofile.local; then
-          . /etc/zprofile.local
-        fi
-      '';
-
-      environment.etc."zshenv".text = ''
-        # /etc/zshenv: DO NOT EDIT -- this file has been generated automatically.
-        # This file is read for all shells.
-
-        # Only execute this file once per shell.
-        # But don't clobber the environment of interactive non-login children!
-
-        if [ -n "$__ETC_ZSHENV_SOURCED" ]; then return; fi
-        export __ETC_ZSHENV_SOURCED=1
-
-        export NIX_PATH=nixpkgs=$HOME/.nix-defexpr/nixpkgs:$HOME/.nix-defexpr/channels_root
-
-        # Set up secure multi-user builds: non-root users build through the
-        # Nix daemon.
-        if [ "$USER" != root -a ! -w /nix/var/nix/db ]; then
-            export NIX_REMOTE=daemon
-        fi
-
-        # Read system-wide modifications.
-        if test -f /etc/zshenv.local; then
-          . /etc/zshenv.local
-        fi
-      '';
-
-      environment.etc."zshrc".text = ''
-        # /etc/zshrc: DO NOT EDIT -- this file has been generated automatically.
-        # This file is read for interactive shells.
-
-        # Only execute this file once per shell.
-        if [ -n "$__ETC_ZSHRC_SOURCED" -o -n "$NOSYSZSHRC" ]; then return; fi
-        __ETC_ZSHRC_SOURCED=1
-
-        # history defaults
-        SAVEHIST=2000
-        HISTSIZE=2000
-        HISTFILE=$HOME/.zsh_history
-
-        setopt HIST_IGNORE_DUPS SHARE_HISTORY HIST_FCNTL_LOCK
-
-        export PATH=${config.environment.systemPath}''${PATH:+:$PATH}
-        typeset -U PATH
-
-        ${config.system.build.setEnvironment}
-        ${config.system.build.setAliases}
-
-        # Read system-wide modifications.
-        if test -f /etc/zshrc.local; then
-          . /etc/zshrc.local
-        fi
-      '';
-    };
-
-  eval = import ../.. { inherit config; };
-
-in
-
+{ config, lib, pkgs, ... }:
 {
-  inherit (eval) config;
-  inherit (eval.config.system) build;
+  environment.systemPackages =
+    [ config.system.build.nix
 
-  packageOverrides = self: {
-    nixdarwin = eval.config.system.build;
+      pkgs.lnl.zsh
+      pkgs.lnl.tmux
+      pkgs.lnl.vim
+      pkgs.curl
+      pkgs.fzf
+      pkgs.gettext
+      pkgs.git
+      pkgs.jq
+      pkgs.silver-searcher
 
-    lnl.zsh = pkgs.runCommand pkgs.zsh.name
-      { buildInputs = [ pkgs.makeWrapper ]; }
-      ''
-        source $stdenv/setup
+      pkgs.nix-repl
+      pkgs.nox
+    ];
 
-        mkdir -p $out/bin
-        makeWrapper "${pkgs.zsh}/bin/zsh" "$out/bin/zsh"
-      '';
+  services.nix-daemon.enable = true;
+  services.nix-daemon.tempDir = "/nix/tmp";
 
-    lnl.tmux = pkgs.runCommand pkgs.tmux.name
-      { buildInputs = [ pkgs.makeWrapper ]; }
-      ''
-        source $stdenv/setup
+  services.activate-system.enable = true;
 
-        mkdir -p $out/bin
-        makeWrapper "${pkgs.tmux}/bin/tmux" "$out/bin/tmux" \
-          --add-flags -f --add-flags "/run/current-system/etc/tmux.conf" \
-      '';
+  system.defaults.global.InitialKeyRepeat = 10;
+  system.defaults.global.KeyRepeat = 1;
 
-    lnl.vim = pkgs.vim_configurable.customize {
-      name = "vim";
-      vimrcConfig.customRC = ''
-        set nocompatible
-        filetype plugin indent on
-        syntax on
+  programs.tmux.loginShell = "${pkgs.lnl.zsh}/bin/zsh -l";
+  programs.tmux.enableSensible = true;
+  programs.tmux.enableMouse = true;
+  programs.tmux.enableFzf = true;
+  programs.tmux.enableVim = true;
 
-        colorscheme solarized
-        set bg=dark
+  programs.tmux.tmuxConfig = ''
+    bind 0 set status
 
-        set et sw=2 ts=2
-        set bs=indent,start
+    set -g status-bg black
+    set -g status-fg white
+  '';
 
-        set nowrap
-        set list
-        set listchars=tab:»·,trail:·,extends:⟩,precedes:⟨
-        set fillchars+=vert:\ ,stl:\ ,stlnc:\ 
+  environment.variables.EDITOR = "vim";
+  environment.variables.HOMEBREW_CASK_OPTS = "--appdir=/Applications/cask";
 
-        set lazyredraw
+  environment.variables.SHELL = "${pkgs.lnl.zsh}/bin/zsh";
 
-        set clipboard=unnamed
+  environment.variables.GIT_SSL_CAINFO = "${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt";
+  environment.variables.SSL_CERT_FILE = "${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt";
 
-        vmap s S
+  environment.shellAliases.l = "ls -lh";
+  environment.shellAliases.ls = "ls -G";
+  environment.shellAliases.g = "git log  --oneline --max-count 42";
+  environment.shellAliases.gl = "git log --graph --oneline";
+  environment.shellAliases.gd = "git diff --minimal --patch";
 
-        cnoremap %% <C-r>=expand('%:h') . '/'<CR>
+  environment.etc."zprofile".text = ''
+    # /etc/zprofile: DO NOT EDIT -- this file has been generated automatically.
+    # This file is read for login shells.
 
-        set hlsearch
-        nnoremap // :nohlsearch<CR>
+    # Only execute this file once per shell.
+    if [ -n "$__ETC_ZPROFILE_SOURCED" ]; then return; fi
+    __ETC_ZPROFILE_SOURCED=1
 
-        let mapleader = ' '
-        nnoremap <Leader>p :FZF<CR>
-        nnoremap <silent> <Leader>e :exe 'FZF ' . expand('%:h')<CR>
+    autoload -U promptinit && promptinit
+    PROMPT='%B%(?..%? )%b⇒ '
+    RPROMPT='%F{green}%~%f'
 
-        source $HOME/.vimrc.local
-      '';
-      # vimrcConfig.vam.knownPlugins = with pkgs.vimUtils; (pkgs.vimPlugins // {
-      #   vim-nix = buildVimPluginFrom2Nix {
-      #     name = "vim-nix-unstable";
-      #     src = ../../../vim-nix;
-      #   };
-      # });
-      vimrcConfig.vam.pluginDictionaries = [
-        { names = [ "fzfWrapper" "youcompleteme" "fugitive" "surround" "vim-nix" "colors-solarized" ]; }
-      ];
-    };
-  };
+    bindkey -e
+    setopt autocd
 
-  allowUnfree = true;
+    autoload -U compinit && compinit
+
+    nix () {
+      cmd=$1
+      shift
+
+      case $cmd in
+        'b'|'build')        nix-build --no-out-link -E "with import <nixpkgs> {}; $@" ;;
+        'e'|'eval')         nix-instantiate --eval -E "with import  <nixpkgs> {}; $@" ;;
+        'i'|'instantiate')  nix-instantiate -E "with import <nixpkgs> {}; $@" ;;
+        'r'|'repl')         nix-repl '<nixpkgs>' ;;
+        's'|'shell')        nix-shell -E "with import <nixpkgs> {}; $@" ;;
+        'p'|'package')      nix-shell '<nixpkgs>' -p "with import <nixpkgs> {}; $@" --run $SHELL ;;
+        'z'|'zsh')          nix-shell '<nixpkgs>' -E "with import <nixpkgs> {}; $@" --run $SHELL ;;
+        'exec')
+          echo "reexecuting shell: $SHELL" >&2
+          __ETC_ZSHRC_SOURCED= \
+          __ETC_ZSHENV_SOURCED= \
+          __ETC_ZPROFILE_SOURCED= \
+            exec $SHELL -l
+          ;;
+      esac
+    }
+
+    conf=$HOME/src/nixpkgs-config
+    pkgs=$HOME/.nix-defexpr/nixpkgs
+
+    # Read system-wide modifications.
+    if test -f /etc/zprofile.local; then
+      . /etc/zprofile.local
+    fi
+  '';
+
+  environment.etc."zshenv".text = ''
+    # /etc/zshenv: DO NOT EDIT -- this file has been generated automatically.
+    # This file is read for all shells.
+
+    # Only execute this file once per shell.
+    # But don't clobber the environment of interactive non-login children!
+
+    if [ -n "$__ETC_ZSHENV_SOURCED" ]; then return; fi
+    export __ETC_ZSHENV_SOURCED=1
+
+    export NIX_PATH=nixpkgs=$HOME/.nix-defexpr/nixpkgs:darwin=$HOME/.nix-defexpr/darwin:darwin-config=$HOME/.nixpkgs/darwin-config.nix:$HOME/.nix-defexpr/channels_root
+
+    # Set up secure multi-user builds: non-root users build through the
+    # Nix daemon.
+    if [ "$USER" != root -a ! -w /nix/var/nix/db ]; then
+        export NIX_REMOTE=daemon
+    fi
+
+    # Read system-wide modifications.
+    if test -f /etc/zshenv.local; then
+      . /etc/zshenv.local
+    fi
+  '';
+
+  environment.etc."zshrc".text = ''
+    # /etc/zshrc: DO NOT EDIT -- this file has been generated automatically.
+    # This file is read for interactive shells.
+
+    # Only execute this file once per shell.
+    if [ -n "$__ETC_ZSHRC_SOURCED" -o -n "$NOSYSZSHRC" ]; then return; fi
+    __ETC_ZSHRC_SOURCED=1
+
+    # history defaults
+    SAVEHIST=2000
+    HISTSIZE=2000
+    HISTFILE=$HOME/.zsh_history
+
+    setopt HIST_IGNORE_DUPS SHARE_HISTORY HIST_FCNTL_LOCK
+
+    export PATH=${config.environment.systemPath}''${PATH:+:$PATH}
+    typeset -U PATH
+
+    ${config.system.build.setEnvironment}
+    ${config.system.build.setAliases}
+
+    # Read system-wide modifications.
+    if test -f /etc/zshrc.local; then
+      . /etc/zshrc.local
+    fi
+  '';
 }
diff --git a/modules/nix/default.nix b/modules/nix/default.nix
new file mode 100644
index 00000000..5c33697e
--- /dev/null
+++ b/modules/nix/default.nix
@@ -0,0 +1,19 @@
+{ config, pkgs, ... }:
+
+let
+
+  tools = pkgs.callPackage ../../pkgs/nix-tools {};
+
+in
+
+{
+  config = {
+
+    system.build.nix = pkgs.runCommand "nix-darwin" {} ''
+      mkdir -p $out/bin
+      ln -s ${tools.darwin-option} $out/bin/darwin-option
+      ln -s ${tools.darwin-rebuild} $out/bin/darwin-rebuild
+    '';
+
+  };
+}
diff --git a/pkgs/nix-tools/default.nix b/pkgs/nix-tools/default.nix
new file mode 100644
index 00000000..acd3bb62
--- /dev/null
+++ b/pkgs/nix-tools/default.nix
@@ -0,0 +1,56 @@
+{ stdenv, writeScript, coreutils, nix }:
+
+{
+  darwin-option = writeScript "darwin-option" ''
+    #! ${stdenv.shell}
+    set -e
+
+    echo "$0: not implemented" >&2
+    exit 1
+  '';
+
+  darwin-rebuild = writeScript "darwin-rebuild" ''
+    #! ${stdenv.shell}
+    set -e
+
+    showSyntax() {
+        exec man darwin-rebuild
+        exit 1
+    }
+
+    # Parse the command line.
+    origArgs=("$@")
+    action=
+    profile=/nix/var/nix/profiles/system
+
+    while [ "$#" -gt 0 ]; do
+        i="$1"; shift 1
+        case "$i" in
+            --help)
+              showSyntax
+              ;;
+            switch|build)
+              action="$i"
+              ;;
+            *)
+              echo "$0: unknown option \`$i'"
+              exit 1
+              ;;
+        esac
+    done
+
+    if [ -z "$action" ]; then showSyntax; fi
+
+    export PATH=${coreutils}/bin:$PATH
+
+    echo "building the system configuration..." >&2
+    if [ "$action" = switch -o "$action" = build ]; then
+        systemConfig="$(nix-build '<darwin>' --no-out-link -A system)"
+    fi
+
+    if [ "$action" = switch ]; then
+        sudo nix-env -p "$profile" --set $systemConfig
+        sudo $systemConfig/activate
+    fi
+  '';
+}