[hytop] Update help messages

projects/hytop/src/hytop/main.py

@@ -37,18 +37,18 @@ def root(
         "localhost",
         "--hosts",
         "-H",
-        help="Comma-separated hosts, e.g. node01,node02. Default: localhost",
+        help="Comma-separated hosts, e.g. node01,node02.",
     ),
     interval: float = typer.Option(
         1.0,
         "--interval",
         "-n",
-        help="Polling interval in seconds. Default: 1.0",
+        help="Polling interval in seconds.",
     ),
     window: float = typer.Option(
         5.0,
         "--window",
-        help="Single rolling window in seconds. Default: 5.0",
+        help="Single rolling window in seconds.",
     ),
     timeout: float | None = typer.Option(
         None,
@@ -57,6 +57,10 @@ def root(
     ),
 ) -> None:
     """Root callback that parses global options and stores them in context."""
+    if ctx.invoked_subcommand is None:
+        typer.echo(ctx.get_help())
+        raise typer.Exit()
+
     try:
         host_list = parse_csv_strings(hosts, "--hosts")
         window_value = parse_positive_float(str(window), "--window")