From fae244f02f414fdb627679bef6f6f4773621101e Mon Sep 17 00:00:00 2001
From: Brad <bradthx@gmail.com>
Date: Sun, 26 Apr 2026 10:39:47 -0400
Subject: [PATCH] Fix Python 3.6 argparse compatibility

---
 README.md | 7 ++++---
 ndrift    | 6 +++++-
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index 95a7a6b..4595f7b 100644
--- a/README.md
+++ b/README.md
@@ -127,9 +127,10 @@ If scan_updates_baseline is true, ndrift updates baseline after each scan.
 ### Requirements
 
 1. Linux
-2. Python 3
-3. optional: lsattr for filesystem attribute checks
-4. optional: AWS CLI for object storage report upload
+2. Python 3.6 or newer
+3. for Python 3.6 only: dataclasses backport package
+4. optional: lsattr for filesystem attribute checks
+5. optional: AWS CLI for object storage report upload
 
 ### Local install in project directory
 
diff --git a/ndrift b/ndrift
index 3090bef..b12a615 100755
--- a/ndrift
+++ b/ndrift
@@ -1268,7 +1268,8 @@ def build_parser() -> argparse.ArgumentParser:
         prog="ndrift",
         description="Lightweight file integrity monitor for Linux",
     )
-    sub = parser.add_subparsers(dest="command", required=True)
+    sub = parser.add_subparsers(dest="command")
+    sub.required = True
 
     init_cmd = sub.add_parser("init", help="create baseline")
     init_cmd.add_argument("directories", nargs="+", help="directories to monitor")
@@ -1338,6 +1339,9 @@ def main(argv: Optional[List[str]] = None) -> int:
     """Main entry point for CLI execution."""
     parser = build_parser()
     args = parser.parse_args(argv)
+    if getattr(args, "command", None) is None:
+        parser.print_help(sys.stderr)
+        return EXIT_ERROR
     try:
         return dispatch(args)
     except NdriftError as exc: