From ef5ef3f603dd9a57344756b70785ecfc16899f66 Mon Sep 17 00:00:00 2001
From: williamleecn <weekgo@gmail.com>
Date: Sun, 18 Jul 2021 01:15:12 +0800
Subject: [PATCH] show usage

show usage when missing argument
---
 main.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/main.go b/main.go
index 0915a18..3e3fd72 100644
--- a/main.go
+++ b/main.go
@@ -29,9 +29,11 @@ func main() {
 		}
 	}()
 	if url == "" {
+		flag.Usage()
 		panicParameter("u")
 	}
 	if output == "" {
+		flag.Usage()
 		panicParameter("o")
 	}
 	if chanSize <= 0 {