diff --git a/pkgs/tools/misc/trashy/default.nix b/pkgs/tools/misc/trashy/default.nix
index 39c725b3cfcb..09cbccb13c77 100644
--- a/pkgs/tools/misc/trashy/default.nix
+++ b/pkgs/tools/misc/trashy/default.nix
@@ -13,7 +13,7 @@ rustPlatform.buildRustPackage rec {
 
   nativeBuildInputs = [ installShellFiles ];
 
-  preFixup = lib.optionalString (stdenv.buildPlatform.canExecute stdenv.hostPlatform) ''
+  postInstall = lib.optionalString (stdenv.buildPlatform.canExecute stdenv.hostPlatform) ''
     installShellCompletion --cmd trash \
       --bash <($out/bin/trash completions bash) \
       --fish <($out/bin/trash completions fish) \