diff --git a/third_party/nix/env.nix b/third_party/nix/env.nix
index 6dcd6f8..4ba3a49 100644
--- a/third_party/nix/env.nix
+++ b/third_party/nix/env.nix
@@ -61,7 +61,7 @@
               readonly workspace_dir
               return
             fi
-            workspace_dir="$(dirname "\''${workspace_dir}")"
+            workspace_dir="\''$(dirname "\''${workspace_dir}")"
           done
           readonly workspace_dir=""
         }