diff --git a/.gitignore b/.gitignore
index 7758836..def4ca2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,5 +11,5 @@ dssWriter.jar
 *.LOC
 *.BIN
 *.dsc
-dssExportJson
+dssExportJson*
 tempPrm.txt
diff --git a/nodejs/prm/cmds/update.js b/nodejs/prm/cmds/update.js
index d256419..3d753a4 100644
--- a/nodejs/prm/cmds/update.js
+++ b/nodejs/prm/cmds/update.js
@@ -4,28 +4,47 @@ var path = require('path');
 var rimraf = require('rimraf');
 var fs = require('fs');
 var runtime = require('../lib/runtime');
+var dirPreFix = 'dssExportJson';
 
 module.exports = function(args, callback) {
   console.log('Running **Update** command.\n');
+  var t = new Date().getTime();
 
   var params = {
     export : true,
     path : path.join(args.output || process.cwd(), args.prefix+'.dss'),
-    exportRoot : path.join(args.output || process.cwd())
+    exportRoot : path.join(args.output || process.cwd(), dirPreFix+'_'+args.prefix),
+    regex : args.regex || '.*FLOW_LOC.*'
   };
 
-  var dir = path.join(params.exportRoot, 'dssExportJson');
+  if( args.cache && !args['clean-cache'] && fs.existsSync(params.exportRoot) ) {
+    // process(args);
+    console.log('Finished update: '+(new Date().getTime() - t)+'ms');
+    callback();
+    return;
+  }
+
+  cleanTmpDir(params.exportRoot, args['clean-cache'], function() {
+    // kill this file
+    var dsc = path.join(args.output || process.cwd(), args.prefix+'.dsc');
+    if( fs.existsSync(dsc) ) {
+      fs.unlinkSync(dsc);
+    }
 
-  cleanTmpDir(dir, function(){
     runtime(args.runtime, params, args, function(){
-      console.log('Finished update');
-      callback();
+      // process(args);
+
+      console.log('Finished update: '+(new Date().getTime() - t)+'ms');
+      cleanTmpDir(params.exportRoot, args.cache, function(){
+        callback();
+      });
+
     });
   });
 };
 
-function cleanTmpDir(dir, callback) {
-  if( fs.existsSync(dir) ) {
+function cleanTmpDir(dir, clearCache, callback) {
+  if( fs.existsSync(dir) && clearCache ) {
     console.log('cleaning dir: '+dir);
     rimraf(dir, callback);
   } else {