diff --git a/default.nix b/default.nix
index ec5f16df..c5376a11 100644
--- a/default.nix
+++ b/default.nix
@@ -11,7 +11,7 @@ let
         ./modules/system/defaults
         ./modules/system/etc.nix
         ./modules/system/launchd.nix
-        ./modules/nix/nix-tools.nix
+        ./modules/nix/nix-darwin.nix
         ./modules/nix/nixpkgs.nix
         ./modules/environment
         ./modules/launchd
diff --git a/modules/nix/nix-darwin.nix b/modules/nix/nix-darwin.nix
new file mode 100644
index 00000000..787c5fa1
--- /dev/null
+++ b/modules/nix/nix-darwin.nix
@@ -0,0 +1,41 @@
+{ config, pkgs, ... }:
+
+let
+
+  inherit (pkgs) stdenv;
+
+  writeProgram = name: env: src:
+    pkgs.substituteAll ({
+      inherit name src;
+      dir = "bin";
+      isExecutable = true;
+    } // env);
+
+  darwin-option = writeProgram "darwin-option"
+    {
+      inherit (config.system) profile;
+      inherit (stdenv) shell;
+    }
+    ../../pkgs/nix-tools/darwin-option.sh;
+
+  darwin-rebuild = writeProgram "darwin-rebuild"
+    {
+      inherit (config.system) profile;
+      inherit (stdenv) shell;
+      path = "${pkgs.coreutils}/bin:${config.environment.systemPath}";
+    }
+    ../../pkgs/nix-tools/darwin-rebuild.sh;
+
+in
+
+{
+  config = {
+
+    environment.systemPackages =
+      [ # Include nix-tools by default
+        darwin-option
+        darwin-rebuild
+      ];
+
+  };
+}
diff --git a/modules/nix/nix-tools.nix b/modules/nix/nix-tools.nix
deleted file mode 100644
index 580244dd..00000000
--- a/modules/nix/nix-tools.nix
+++ /dev/null
@@ -1,19 +0,0 @@
-{ config, pkgs, ... }:
-
-let
-
-  tools = pkgs.callPackage ../../pkgs/nix-tools {};
-
-in
-
-{
-  config = {
-
-    environment.systemPackages =
-      [ # Include nix-tools by default
-        tools.darwin-option
-        tools.darwin-rebuild
-      ];
-
-  };
-}
diff --git a/modules/system/activation-scripts.nix b/modules/system/activation-scripts.nix
index 3948fccf..2695e54f 100644
--- a/modules/system/activation-scripts.nix
+++ b/modules/system/activation-scripts.nix
@@ -38,6 +38,9 @@ in
 
     system.activationScripts.script.text = ''
       #! ${stdenv.shell}
+      set -e
+      set -o pipefail
+      export PATH=${pkgs.coreutils}/bin:${config.environment.systemPath}:$PATH
 
       systemConfig=@out@
 
diff --git a/pkgs/nix-tools/darwin-option.sh b/pkgs/nix-tools/darwin-option.sh
new file mode 100755
index 00000000..798317b7
--- /dev/null
+++ b/pkgs/nix-tools/darwin-option.sh
@@ -0,0 +1,12 @@
+#! @shell@
+set -e
+set -o pipefail
+export PATH=@path@:$PATH
+
+
+showSyntax() {
+    echo "$0: not implemented" >&2
+    exit 1
+}
+
+showSyntax
diff --git a/pkgs/nix-tools/darwin-rebuild.sh b/pkgs/nix-tools/darwin-rebuild.sh
new file mode 100644
index 00000000..898adcae
--- /dev/null
+++ b/pkgs/nix-tools/darwin-rebuild.sh
@@ -0,0 +1,42 @@
+#! @shell@
+set -e
+set -o pipefail
+export PATH=@path@:$PATH
+
+
+showSyntax() {
+    exec man darwin-rebuild
+    exit 1
+}
+
+# Parse the command line.
+origArgs=("$@")
+action=
+
+while [ "$#" -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 "$action" ]; then showSyntax; fi
+
+echo "building the system configuration..." >&2
+if [ "$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
diff --git a/pkgs/nix-tools/default.nix b/pkgs/nix-tools/default.nix
deleted file mode 100644
index a6dd4fad..00000000
--- a/pkgs/nix-tools/default.nix
+++ /dev/null
@@ -1,56 +0,0 @@
-{ stdenv, writeScriptBin, coreutils, nix }:
-
-{
-  darwin-option = writeScriptBin "darwin-option" ''
-    #! ${stdenv.shell}
-    set -e
-
-    echo "$0: not implemented" >&2
-    exit 1
-  '';
-
-  darwin-rebuild = writeScriptBin "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
-  '';
-}