diff --git a/README.md b/README.md
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--- /dev/null
+++ b/README.md
@@ -0,0 +1,5 @@
+# NixOS Tutorial
+This is a working repo for learning how to develop in NixOS and configure systems. 
+
+## Material
+I'm currently following the tutorials at [Nix.dev](https://nix.dev/tutorials/)
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diff --git a/callPackage/default.nix b/callPackage/default.nix
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+++ b/callPackage/default.nix
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+let 
+  pkgs = import <nixpkgs> { };
+in 
+rec{
+  hello = pkgs.callPackage ./hello.nix { audience = "people"; };
+  hello-folks = hello.override { audience = "folks"; };
+}
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diff --git a/callPackage/hello.nix b/callPackage/hello.nix
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index 0000000..2dc0740
--- /dev/null
+++ b/callPackage/hello.nix
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+{ 
+  writeShellScriptBin,
+  audience ? "world",
+}:
+writeShellScriptBin "hello" ''
+  echo "Hello, ${audience}!"
+''
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