diff --git a/tools/ndngetfile.cpp b/tools/ndngetfile.cpp
index fd9dc6a..50f8ab3 100644
--- a/tools/ndngetfile.cpp
+++ b/tools/ndngetfile.cpp
@@ -25,12 +25,14 @@
 
 using namespace ndn;
 
+static const int MAX_RETRY = 3;
+
 void
 Consumer::fetchData(const Name& name)
 {
   Interest interest(name);
   interest.setInterestLifetime(m_interestLifetime);
-
+  //std::cout<<"interest name = "<<interest.getName()<<std::endl;
   if (m_hasVersion)
     {
       interest.setMustBeFresh(m_mustBeFresh);
@@ -42,7 +44,10 @@
     }
 
   m_face.expressInterest(interest,
-                         bind(&Consumer::onData, this, _1, _2),
+                         m_hasVersion ?
+                           bind(&Consumer::onVersionedData, this, _1, _2)
+                           :
+                           bind(&Consumer::onUnversionedData, this, _1, _2),
                          bind(&Consumer::onTimeout, this, _1));
 }
 
@@ -51,10 +56,8 @@
 {
   // Send the first Interest
   Name name(m_dataName);
-  if (m_hasVersion)
-    // If '-u' is specified, we already have version number in the name
-    name.appendSegment(m_nextSegment++);
 
+  m_nextSegment++;
   fetchData(name);
 
   // processEvents will block until the requested data received or timeout occurs
@@ -62,71 +65,121 @@
 }
 
 void
-Consumer::onData(const Interest& interest, Data& data)
+Consumer::onVersionedData(const Interest& interest, Data& data)
 {
   const Name& name = data.getName();
-  if (name.size() != m_dataName.size() + (m_hasVersion ? 1 : 2))
-    throw std::invalid_argument("unexpected data name size.");
 
-  uint64_t segment = name[-1].toSegment();
-
-  if (!m_hasVersion)
-    {
-      // Assume the second to last component is the version number
-      // and the last component is the segment number
-      m_dataName.append(name[-2]);
-      m_hasVersion = true;
-      if (m_verbose)
-        {
-          std::cerr << "LOG: version number is " << name[-2].toVersion() << std::endl;
-        }
-
-      if (segment != 0)
-        {
-          // Discard this segment and fetch the first segment
-          fetchData(Name(m_dataName).appendSegment(m_nextSegment++));
+  // the received data name may have segment number or not
+  if (name.size() == m_dataName.size()) {
+    if (!m_isSingle) {
+      Name fetchName = name;
+      fetchName.appendSegment(0);
+      fetchData(fetchName);
+    }
+  }
+  else if (name.size() == m_dataName.size() + 1) {
+    if (!m_isSingle) {
+      if (m_isFirst) {
+        uint64_t segment = name[-1].toSegment();
+        if (segment != 0) {
+          fetchData(Name(m_dataName).appendSegment(0));
+          m_isFirst = false;
           return;
         }
-
-      m_nextSegment++;
+        m_isFirst = false;
+      }
+      fetchNextData(name, data);
     }
+    else {
+      std::cerr << "ERROR: Data is not stored in a single packet" << std::endl;
+      return;
+    }
+  }
+  else {
+    std::cerr << "ERROR: Name size does not match" << std::endl;
+    return;
+  }
+  readData(data);
+}
 
-  BOOST_ASSERT(segment == (m_nextSegment - 1));
+void
+Consumer::onUnversionedData(const Interest& interest, Data& data)
+{
+  const Name& name = data.getName();
+  //std::cout<<"recevied data name = "<<name<<std::endl;
+  if (name.size() == m_dataName.size() + 1) {
+    if (!m_isSingle) {
+      Name fetchName = name;
+      fetchName.append(name[-1]).appendSegment(0);
+      fetchData(fetchName);
+    }
+  }
+  else if (name.size() == m_dataName.size() + 2) {
+    if (!m_isSingle) {
+       if (m_isFirst) {
+        uint64_t segment = name[-1].toSegment();
+        if (segment != 0) {
+          fetchData(Name(m_dataName).append(name[-2]).appendSegment(0));
+          m_isFirst = false;
+          return;
+        }
+        m_isFirst = false;
+      }
+      fetchNextData(name, data);
+    }
+    else {
+      std::cerr << "ERROR: Data is not stored in a single packet" << std::endl;
+      return;
+    }
+  }
+  else {
+    std::cerr << "ERROR: Name size does not match" << std::endl;
+    return;
+  }
+  readData(data);
+}
 
-  // Output the current segment
+void
+Consumer::readData(const Data& data)
+{
   const Block& content = data.getContent();
   m_os.write(reinterpret_cast<const char*>(content.value()), content.value_size());
   m_totalSize += content.value_size();
   if (m_verbose)
-    {
-      std::cerr << "LOG: received segment #" << segment << std::endl;
-    }
-
-  // Check final block id
-  const name::Component& finalBlockId = data.getMetaInfo().getFinalBlockId();
-  if (finalBlockId == name[-1])
-    {
-      // Reach EOF
-      std::cerr << "INFO: End of file is reached." << std::endl;
-      std::cerr << "INFO: Total # of segments received: " << (m_nextSegment - 1) << std::endl;
-      std::cerr << "INFO: Total # bytes of content received: " << m_totalSize << std::endl;
-    }
-  else
-    {
-      // Reset retry counter
-      m_retryCount = 0;
-
-      // Fetch next segment
-      fetchData(Name(m_dataName).appendSegment(m_nextSegment++));
-    }
+  {
+    std::cerr << "LOG: received data = " << data.getName() << std::endl;
+  }
+  if (m_isFinished || m_isSingle) {
+    std::cerr << "INFO: End of file is reached." << std::endl;
+    std::cerr << "INFO: Total # of segments received: " << m_nextSegment  << std::endl;
+    std::cerr << "INFO: Total # bytes of content received: " << m_totalSize << std::endl;
+  }
 }
 
-const int Consumer::MAX_RETRY = 3;
+void
+Consumer::fetchNextData(const Name& name, const Data& data)
+{
+  uint64_t segment = name[-1].toSegment();
+  BOOST_ASSERT(segment == (m_nextSegment - 1));
+  const name::Component& finalBlockId = data.getMetaInfo().getFinalBlockId();
+  if (finalBlockId == name[-1]) {
+    m_isFinished = true;
+  }
+  else
+  {
+    // Reset retry counter
+    m_retryCount = 0;
+    if (m_hasVersion)
+      fetchData(Name(m_dataName).appendSegment(m_nextSegment++));
+    else
+      fetchData(Name(m_dataName).append(name[-2]).appendSegment(m_nextSegment++));
+  }
+}
 
 void
 Consumer::onTimeout(const Interest& interest)
 {
-  if (m_retryCount++ < Consumer::MAX_RETRY)
+  if (m_retryCount++ < MAX_RETRY)
     {
       // Retransmit the interest
       fetchData(interest.getName());
@@ -138,7 +191,7 @@
   else
     {
       std::cerr << "TIMEOUT: last interest sent for segment #" << (m_nextSegment - 1) << std::endl;
-      std::cerr << "TIMEOUT: abort fetching after " << Consumer::MAX_RETRY
+      std::cerr << "TIMEOUT: abort fetching after " << MAX_RETRY
                 << " times of retry" << std::endl;
     }
 }
@@ -148,14 +201,15 @@
 usage(const std::string& filename)
 {
   std::cerr << "Usage: \n    "
-            << filename << " [-v] [-u] [-l lifetime] [-w timeout] [-o filename] ndn-name\n\n"
+            << filename << " [-v] [-s] [-u] [-l lifetime] [-w timeout] [-o filename] ndn-name\n\n"
             << "-v: be verbose\n"
-            << "-u: unversioned: do not try to find the latest version; "
-               "ndn-name contains version component\n"
-            << "ndn-name: NDN Name prefix for Data to be read\n"
+            << "-s: only get single data packet\n"
+            << "-u: versioned: ndn-name contains version component\n"
+            << "    if -u is not specified, this command will return the rightmost child for the prefix\n"
             << "-l: InterestLifetime in milliseconds\n"
             << "-w: timeout in milliseconds for whole process (default unlimited)\n"
-            << "-o: write to local file name instead of stdout\n";
+            << "-o: write to local file name instead of stdout\n"
+            << "ndn-name: NDN Name prefix for Data to be read\n";
   return 1;
 }
 
@@ -165,19 +219,22 @@
 {
   std::string name;
   const char* outputFile = 0;
-  bool verbose = false, unversioned = false;
+  bool verbose = false, versioned = false, single = false;
   int interestLifetime = 4000;  // in milliseconds
   int timeout = 0;  // in milliseconds
 
   int opt;
-  while ((opt = getopt(argc, argv, "vul:w:o:")) != -1)
+  while ((opt = getopt(argc, argv, "vsul:w:o:")) != -1)
     {
       switch (opt) {
       case 'v':
         verbose = true;
         break;
+      case 's':
+        single = true;
+        break;
       case 'u':
-        unversioned = true;
+        versioned = true;
         break;
       case 'l':
         try
@@ -241,7 +298,7 @@
 
   std::ostream os(buf);
 
-  Consumer consumer(name, os, verbose, unversioned,
+  Consumer consumer(name, os, verbose, versioned, single,
                     interestLifetime, timeout);
 
   try