diff --git a/pkgs/build-support/docker/examples.nix b/pkgs/build-support/docker/examples.nix
index 074e37b61d8c..a37cdd004c04 100644
--- a/pkgs/build-support/docker/examples.nix
+++ b/pkgs/build-support/docker/examples.nix
@@ -704,7 +704,7 @@ rec {
           finalAttrs: prevAttrs: {
             # A unique `hello` to make sure that it isn't included via another mechanism by accident.
             configureFlags = prevAttrs.configureFlags or [ ] ++ [
-              " --program-prefix=layeredImageWithFakeRootCommands-"
+              "--program-prefix=layeredImageWithFakeRootCommands-"
             ];
             doCheck = false;
             versionCheckProgram = "${placeholder "out"}/bin/${finalAttrs.meta.mainProgram}";