diff --git a/bin/dns-pack.js b/bin/dns-pack.js
index b1d08b1..ddb6973 100644
--- a/bin/dns-pack.js
+++ b/bin/dns-pack.js
@@ -3,12 +3,22 @@
 // EXAMPLE:
 // node bin/dns-parse.js samples/a-0.mdns.bin
 
+var path = require('path');
 // pass a terminal arg
 var filename = process.argv[2];
+var outname = process.argv[3];
 if (!filename) {
-  console.error("Usage: node bin/dns-pack.js <path/to/sample.json>");
-  console.error("Example: node bin/dns-pack.js ./samples/services-0.mdns.json");
+  console.error("Usage: node bin/dns-pack.js <path/to/sample.json> <path/to/output.bin>");
+  console.error("Example: node bin/dns-pack.js ./samples/services-0.mdns.json ./services-0.mdns.bin");
   process.exit(1);
+  return;
+}
+if (!outname) {
+  console.warn('');
+  console.warn(
+    "Usage: node bin/dns-pack.js '" + filename + "' './" + path.basename(filename).replace(path.extname(filename), '') + ".bin'"
+  );
+  console.warn('');
 }
 
 
@@ -32,10 +42,20 @@ fs.readFileAsync(filename, null).then(function (nb) {
   // nb.buffer is the actual ArrayBuffer
 
   //var ab = nb.buffer.slice(nb.byteOffset, nb.byteOffset + nb.byteLength);
-  var packet = dnsjs.write(JSON.parse(buffer.toString('ascii')));
+  var packet = dnsjs.write(JSON.parse(nb.toString('ascii')));
 
   //console.log('[packet]', nb.byteLength, 'bytes:');
   //console.log(JSON.stringify(packet, null, 2));
 
   //TODO hexdump packet
+  var hexdump = require('hexdump.js').hexdump;
+  var str = hexdump(packet);
+
+  console.log(str);
+
+  if (outname) {
+    fs.writeFileSync(outname, packet, null);
+    console.log('');
+    console.log("wrote '" + outname + "'");
+  }
 });