CUSP-1346 - Add support for existing-folders

Signed-off-by: Stephen Simpson <ssimpson89@users.noreply.github.com>

src/rocky_man/main.py

@@ -254,6 +254,13 @@ def main():
         help="Use vault directory instead of pub (vault/rocky instead of pub/rocky)",
     )
 
+    parser.add_argument(
+        "--existing-versions",
+        nargs="*",
+        metavar="VERSION",
+        help="List of existing versions to include in root index (e.g., 8.10 9.7)",
+    )
+
     parser.add_argument(
         "--template-dir",
         type=Path,
@@ -333,13 +340,24 @@ def main():
         allow_all_sections=args.allow_all_sections,
     )
 
-    # Scan for existing versions in output directory
-    existing_versions = [
+    # Get existing versions from scan and argument
+    scanned_versions = [
         d.name
         for d in config.output_dir.iterdir()
         if d.is_dir() and re.match(r"\d+\.\d+", d.name)
     ]
-    all_versions = sorted(set(existing_versions + config.versions))
+    arg_versions = args.existing_versions or []
+
+    # Sort versions numerically by (major, minor)
+    def version_key(v):
+        try:
+            major, minor = v.split(".")
+            return (int(major), int(minor))
+        except (ValueError, AttributeError):
+            return (0, 0)
+
+    existing_versions = sorted(set(scanned_versions + arg_versions), key=version_key)
+    all_versions = sorted(set(existing_versions + config.versions), key=version_key)
 
     logger.info("Rocky Man - Rocky Linux Man Page Generator")
     logger.info(f"Versions to process: {', '.join(config.versions)}")