Initial commit

hello-versions/shell.nix

@@ -0,0 +1,16 @@
+# https://lazamar.co.uk/nix-versions/
+
+# The following will:
+# - load <nixpkgs> to get the pkgs.mkShell lambda
+# - load the given tarball (zsh 5.4.2 in channel unstable)
+# - start a shell with this old version of zsh
+
+{ 
+  oldpkgs ? (import (fetchTarball "https://github.com/NixOS/nixpkgs/archive/473b58f20e491312a03c9c1578c89116e39a1d50.tar.gz") {}),
+  pkgs ? (import <nixpkgs> {})
+}:
+pkgs.mkShell {
+  packages = [
+    oldpkgs.zsh
+  ];
+}