diff --git a/src/lib/interactive.ml b/src/lib/interactive.ml
index 5f58231..dc1fdb2 100644
--- a/src/lib/interactive.ml
+++ b/src/lib/interactive.ml
@@ -69,6 +69,11 @@ module Make (S : Types.State) (E : Types.Exec) = struct
 
   let h = ref []
 
+  let add_history c =
+    let c = String.trim c in
+    let new_h = List.filter (fun s -> not (String.equal c s)) !h in
+    h := c :: new_h
+
   let history prefix =
     if prefix <> "" then List.filter (fun s -> String.starts_with ~prefix s) !h
     else !h
@@ -90,7 +95,7 @@ module Make (S : Types.State) (E : Types.Exec) = struct
       | String (Some c) ->
           let ast = Ast.of_string (String.trim c) in
           let ctx', _ast = Eval.run ctx ast in
-          h := c :: !h;
+          add_history c;
           loop ctx'
       | Ctrl_c ->
           let c = Exit.value ctx in