diff --git a/pkgs/by-name/ni/nixos-rebuild-ng/package.nix b/pkgs/by-name/ni/nixos-rebuild-ng/package.nix
index 4df882fc176a..e5a4796136de 100644
--- a/pkgs/by-name/ni/nixos-rebuild-ng/package.nix
+++ b/pkgs/by-name/ni/nixos-rebuild-ng/package.nix
@@ -47,7 +47,9 @@ python3Packages.buildPythonApplication rec {
 
   postPatch = ''
     substituteInPlace nixos_rebuild/__init__.py \
-      --subst-var-by executable ${executable}
+      --subst-var-by executable ${executable} \
+      --subst-var-by withShellFiles ${lib.boolToString withShellFiles}
+
     substituteInPlace pyproject.toml \
       --subst-var-by executable ${executable}
   '';
diff --git a/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/__init__.py b/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/__init__.py
index d1a6ca84c7ca..bdec4797e5c3 100644
--- a/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/__init__.py
+++ b/pkgs/by-name/ni/nixos-rebuild-ng/src/nixos_rebuild/__init__.py
@@ -180,6 +180,14 @@ def parse_args(
         for group, parser in sub_parsers.items()
     }
 
+    if args.help or args.action is None:
+        if "@withShellFiles@" == "true":
+            r = run(["man", "8", "@executable@"], check=False)
+            parser.exit(r.returncode)
+        else:
+            parser.print_help()
+            parser.exit()
+
     def parser_warn(msg: str) -> None:
         print(f"{parser.prog}: warning: {msg}", file=sys.stderr)
 
@@ -194,10 +202,6 @@ def parse_args(
     if args.ask_sudo_password:
         args.sudo = True
 
-    if args.help or args.action is None:
-        r = run(["man", "8", "@executable@"], check=False)
-        parser.exit(r.returncode)
-
     # TODO: use deprecated=True in Python >=3.13
     if args.install_grub:
         parser_warn("--install-grub deprecated, use --install-bootloader instead")