diff --git a/lualib/skynet.lua b/lualib/skynet.lua
index 463048fe..5064c7ae 100644
--- a/lualib/skynet.lua
+++ b/lualib/skynet.lua
@@ -343,7 +343,7 @@ function skynet.exit()
 end
 
 function skynet.getenv(key)
-	return c.command("GETENV",key)
+	return (c.command("GETENV",key))
 end
 
 function skynet.setenv(key, value)