diff --git a/bytebeat_compiler.py b/bytebeat_compiler.py
index a70f36e..4057779 100644
--- a/bytebeat_compiler.py
+++ b/bytebeat_compiler.py
@@ -61,7 +61,7 @@ if __name__ == "__main__":
 		"environmental variables `CC`, `CC_FLAGS`, `INPUT_FILE`, "
 		"`OUTPUT_FILE`.")
 	parser.add_argument("file", type=str,
-		help="bytebeat formula file")
+		help="bytebeat formula file (use `-` to read from stdin)")
 	parser.add_argument("-r", "--sample-rate", default=8000, type=int,
 		help="sample rate (Hz)")
 	parser.add_argument("-p", "--final-sample-rate", default=None, type=int,