diff --git a/src/nix/repl.md b/src/nix/repl.md
index 23ef0f4e6..c5113be61 100644
--- a/src/nix/repl.md
+++ b/src/nix/repl.md
@@ -36,7 +36,7 @@ R""(
   Loading Installable ''...
   Added 1 variables.
 
-  # nix repl --extra_experimental_features 'flakes repl-flake' nixpkgs
+  # nix repl --extra-experimental-features 'flakes repl-flake' nixpkgs
   Loading Installable 'flake:nixpkgs#'...
   Added 5 variables.