diff --git a/tools/peek/ndnpoke/main.cpp b/tools/peek/ndnpoke/main.cpp
index f2a6830..a3e5ec2 100644
--- a/tools/peek/ndnpoke/main.cpp
+++ b/tools/peek/ndnpoke/main.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2021,  Regents of the University of California,
+ * Copyright (c) 2014-2022,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
@@ -33,13 +33,12 @@
 #include <boost/program_options/parsers.hpp>
 #include <boost/program_options/variables_map.hpp>
 
-namespace ndn {
-namespace peek {
+namespace ndn::peek {
 
 namespace po = boost::program_options;
 
 static void
-usage(std::ostream& os, const std::string& program, const po::options_description& options)
+usage(std::ostream& os, std::string_view program, const po::options_description& options)
 {
   os << "Usage: " << program << " [options] /name\n"
      << "\n"
@@ -167,8 +166,7 @@
   }
 }
 
-} // namespace peek
-} // namespace ndn
+} // namespace ndn::peek
 
 int
 main(int argc, char* argv[])
diff --git a/tools/peek/ndnpoke/ndnpoke.cpp b/tools/peek/ndnpoke/ndnpoke.cpp
index d31a939..27feb17 100644
--- a/tools/peek/ndnpoke/ndnpoke.cpp
+++ b/tools/peek/ndnpoke/ndnpoke.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2019,  Regents of the University of California,
+ * Copyright (c) 2014-2022,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
@@ -30,8 +30,7 @@
 
 #include <ndn-cxx/encoding/buffer-stream.hpp>
 
-namespace ndn {
-namespace peek {
+namespace ndn::peek {
 
 NdnPoke::NdnPoke(Face& face, KeyChain& keyChain, std::istream& input, const PokeOptions& options)
   : m_options(options)
@@ -123,11 +122,10 @@
 }
 
 void
-NdnPoke::onRegFailure(const std::string& reason)
+NdnPoke::onRegFailure(std::string_view reason)
 {
   m_result = Result::PREFIX_REG_FAIL;
   std::cerr << "Prefix registration failure (" << reason << ")" << std::endl;
 }
 
-} // namespace peek
-} // namespace ndn
+} // namespace ndn::peek
diff --git a/tools/peek/ndnpoke/ndnpoke.hpp b/tools/peek/ndnpoke/ndnpoke.hpp
index 5ffd8cf..16a3795 100644
--- a/tools/peek/ndnpoke/ndnpoke.hpp
+++ b/tools/peek/ndnpoke/ndnpoke.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2019,  Regents of the University of California,
+ * Copyright (c) 2014-2022,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
@@ -33,8 +33,7 @@
 
 #include <ndn-cxx/util/scheduler.hpp>
 
-namespace ndn {
-namespace peek {
+namespace ndn::peek {
 
 /**
  * \brief options for NdnPoke
@@ -53,7 +52,7 @@
   optional<time::milliseconds> timeout;
 };
 
-class NdnPoke : boost::noncopyable
+class NdnPoke : noncopyable
 {
 public:
   NdnPoke(Face& face, KeyChain& keyChain, std::istream& input, const PokeOptions& options);
@@ -93,7 +92,7 @@
   onRegSuccess();
 
   void
-  onRegFailure(const std::string& reason);
+  onRegFailure(std::string_view reason);
 
 private:
   const PokeOptions m_options;
@@ -106,7 +105,6 @@
   Result m_result = Result::UNKNOWN;
 };
 
-} // namespace peek
-} // namespace ndn
+} // namespace ndn::peek
 
 #endif // NDN_TOOLS_NDNPOKE_NDNPOKE_HPP