Default key output to ~/.ssh/ and create the directory if needed

keygen.py

@@ -53,6 +53,7 @@ def save_keypair(
 
     pub_path = path.with_suffix("").parent / (path.name + ".pub")
 
+    path.parent.mkdir(mode=0o700, parents=True, exist_ok=True)
     path.write_bytes(private_bytes)
     path.chmod(0o600)
     pub_path.write_bytes(public_bytes + b"\n")
@@ -145,9 +146,9 @@ def build_parser() -> argparse.ArgumentParser:
     shared = argparse.ArgumentParser(add_help=False)
     shared.add_argument(
         "-o", "--output",
-        default="id_ed25519",
+        default=str(Path.home() / ".ssh" / "id_ed25519"),
         metavar="PATH",
-        help="output path for the private key (default: id_ed25519)",
+        help="output path for the private key (default: ~/.ssh/id_ed25519)",
     )
     shared.add_argument(
         "-C", "--comment",