diff --git a/pkgs/tools/package-management/nix/unstable.nix b/pkgs/tools/package-management/nix/unstable.nix
index 891126128924..bfea62c4f4ce 100644
--- a/pkgs/tools/package-management/nix/unstable.nix
+++ b/pkgs/tools/package-management/nix/unstable.nix
@@ -4,13 +4,12 @@
 }:
 
 stdenv.mkDerivation {
-  name = "nix-0.11pre8816";
+  name = "nix-0.11pre9121";
   
-  src =   
-	fetchurl {
-		url = http://nix.cs.uu.nl/dist/nix/nix-unstable-latest/nix-0.11pre9063.tar.bz2;
-		sha256 = "0fxsvam0ihzcfg694d28d6b3vkx5klh25jvf3y5igyyqszmmhnxj";
-	};
+  src = fetchurl {
+    url = http://nix.cs.uu.nl/dist/nix/nix-0.11pre9121/nix-0.11pre9121.tar.bz2;
+    sha256 = "0yd84g8gyl1xnb0ki0ssy270ff6bs4xy3mjf2ixa7xj9ch3hbyhm";
+  };
 
   buildInputs = [perl curl openssl];
 
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index ac037f80a7a6..cf72e7d2d8ba 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -220,6 +220,8 @@ rec {
   # derivations, e.g., "... ${somePkg}/bin/foo ...".
   writeText = name: text: runCommand name {inherit text;} "echo -n \"$text\" > $out";
 
+  writeScript = name: text: runCommand name {inherit text;} "echo -n \"$text\" > $out; chmod +x $out";
+  
   stdenvNewSetupScript = overrideSetup stdenv ../stdenv/generic/setup-new.sh;
 
   substituteAll = import ../build-support/substitute/substitute-all.nix {