diff --git a/lib/sys.js b/lib/sys.js
index dbdd21bf527..da749db8dc9 100644
--- a/lib/sys.js
+++ b/lib/sys.js
@@ -3,15 +3,15 @@ exports.print = function (x) {
 };
 
 exports.puts = function (x) {
-  process.stdio.write(x.toString() + "\n");
+  process.stdio.write(x + "\n");
 };
 
 exports.debug = function (x) {
-  process.stdio.writeError("DEBUG: " + x.toString() + "\n");
+  process.stdio.writeError("DEBUG: " + x + "\n");
 };
 
 exports.error = function (x) {
-  process.stdio.writeError(x.toString() + "\n");
+  process.stdio.writeError(x + "\n");
 };
 
 /**