diff --git a/tools/peek/ndnpeek/main.cpp b/tools/peek/ndnpeek/main.cpp
index 22523b7..0bfb677 100644
--- a/tools/peek/ndnpeek/main.cpp
+++ b/tools/peek/ndnpeek/main.cpp
@@ -41,13 +41,12 @@
 #include <cstring>
 #include <fstream>
 
-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"
@@ -203,8 +202,7 @@
   }
 }
 
-} // namespace peek
-} // namespace ndn
+} // namespace ndn::peek
 
 int
 main(int argc, char* argv[])
diff --git a/tools/peek/ndnpeek/ndnpeek.cpp b/tools/peek/ndnpeek/ndnpeek.cpp
index 01fd6de..d58b92e 100644
--- a/tools/peek/ndnpeek/ndnpeek.cpp
+++ b/tools/peek/ndnpeek/ndnpeek.cpp
@@ -29,8 +29,7 @@
 
 #include "ndnpeek.hpp"
 
-namespace ndn {
-namespace peek {
+namespace ndn::peek {
 
 NdnPeek::NdnPeek(Face& face, const PeekOptions& options)
   : m_options(options)
@@ -132,5 +131,4 @@
   }
 }
 
-} // namespace peek
-} // namespace ndn
+} // namespace ndn::peek
diff --git a/tools/peek/ndnpeek/ndnpeek.hpp b/tools/peek/ndnpeek/ndnpeek.hpp
index ce37712..eba1b1f 100644
--- a/tools/peek/ndnpeek/ndnpeek.hpp
+++ b/tools/peek/ndnpeek/ndnpeek.hpp
@@ -35,8 +35,7 @@
 #include <ndn-cxx/link.hpp>
 #include <ndn-cxx/util/scheduler.hpp>
 
-namespace ndn {
-namespace peek {
+namespace ndn::peek {
 
 /**
  * @brief options for NdnPeek
@@ -58,7 +57,7 @@
   optional<time::milliseconds> timeout;
 };
 
-class NdnPeek : boost::noncopyable
+class NdnPeek : noncopyable
 {
 public:
   NdnPeek(Face& face, const PeekOptions& options);
@@ -119,7 +118,6 @@
   Result m_result = Result::UNKNOWN;
 };
 
-} // namespace peek
-} // namespace ndn
+} // namespace ndn::peek
 
 #endif // NDN_TOOLS_NDNPEEK_NDNPEEK_HPP