diff --git a/shell.nix b/shell.nix
new file mode 100644
index 0000000..fe83e9b
--- /dev/null
+++ b/shell.nix
@@ -0,0 +1,8 @@
+let
+  pkgs = import <nixpkgs> {};
+in with pkgs;
+mkShell {
+
+  TCLLIBPATH = "${tcllib}/lib/tcllib1.19";
+  buildInputs = [ tcl-8_6 tcllib xfsprogs coreutils ];
+}
diff --git a/xfs_undelete b/xfs_undelete
index 1286d1c..4145d36 100755
--- a/xfs_undelete
+++ b/xfs_undelete
@@ -1,4 +1,4 @@
-#!/usr/bin/tclsh
+#!/usr/bin/env tclsh
 ##
 ## Copyright (c) 2019 Jan Kandziora <jjj@gmx.de>
 ##