diff --git a/_demo/flagdemo/flagdemo.go b/_demo/flagdemo/flagdemo.go
new file mode 100644
index 00000000..b63dd7ab
--- /dev/null
+++ b/_demo/flagdemo/flagdemo.go
@@ -0,0 +1,21 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+)
+
+func main() {
+	fmt.Println("os.Args:", os.Args)
+	if len(os.Args) == 1 {
+		os.Args = []string{"flagdemo", "-cpu", "100"}
+	}
+
+	verbose := flag.Bool("v", false, "verbose")
+	cpu := flag.Int("cpu", 1, "cpu number")
+	host := flag.String("host", ":8888", "host")
+	flag.Parse()
+
+	fmt.Println("host:", *host, "cpu:", *cpu, "verbose:", *verbose)
+}