diff --git a/config.go b/config.go
index da0293b..95dd20f 100644
--- a/config.go
+++ b/config.go
@@ -44,7 +44,7 @@ func NewConfig() (*Config, error) {
 	fs.StringVar(&c.Cert.CRT, "crt", "", "path to .crt")
 	fs.StringVar(&c.Cert.Key, "key", "", "path to .key")
 	fs.IntVar(&c.Port, "p", 56112, "port to listen on")
-	f := fs.String("f", "/dev/null", `file of {domains:{.google.com:{mail:{to: scheme://host:port, basicAuth: u:p, redir: false}}}}`)
+	f := fs.String("f", "/dev/null", `file of {domains:{.google.com:{mail:{to: scheme://host:port, basicAuth: u:p, redir: false, if:{headers:{k:v}, then:{to:...}}}}}}`)
 	if err := fs.Parse(os.Args[1:]); err != nil {
 		return c, err
 	}