diff --git a/notes.adoc b/notes.adoc
index ec04b1f..80af76d 100644
--- a/notes.adoc
+++ b/notes.adoc
@@ -68,3 +68,17 @@ ec4c5890c8a75e93e1bb768f998e49ae7d2bf005e5e7c2a57dd2813b881e9758
 podman run --rm ec4c5890c8a7
 
 Hi, PHP Thames Valley!
+
+=== Using shell.nix
+
+nix-shell
+
+[nix-shell:~/php-thames-valley]$ php index.php
+
+Hi, PHP Thames Valley
+
+==== Running a command without entering a shell
+
+nix-shell --run "php index.php"
+
+Hi, PHP Thames Valley!
diff --git a/shell.nix b/shell.nix
new file mode 100644
index 0000000..d6d8241
--- /dev/null
+++ b/shell.nix
@@ -0,0 +1,7 @@
+{
+  pkgs ? import <nixpkgs> { },
+}:
+
+pkgs.mkShell {
+  packages = [ pkgs.php ];
+}