ndnsec: add a short description to the `--help` output of each command

Change-Id: Ifcc217bb096f1f27bceb609f5f117cf8b1d0c73d
diff --git a/tools/ndnsec/cert-dump.cpp b/tools/ndnsec/cert-dump.cpp
index 0baf8df..3b4f9cf 100644
--- a/tools/ndnsec/cert-dump.cpp
+++ b/tools/ndnsec/cert-dump.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2023 Regents of the University of California.
+ * Copyright (c) 2013-2024 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -43,6 +43,8 @@
   po::options_description description(
     "Usage: ndnsec cert-dump [-h] [-p] [-r [-H HOST] [-P PORT]] [-i|-k|-f] [-n] NAME\n"
     "\n"
+    "Display a certificate from a file or the local PIB.\n"
+    "\n"
     "Options");
   description.add_options()
     ("help,h", "produce help message")
diff --git a/tools/ndnsec/cert-gen.cpp b/tools/ndnsec/cert-gen.cpp
index e7c49ad..ae60efd 100644
--- a/tools/ndnsec/cert-gen.cpp
+++ b/tools/ndnsec/cert-gen.cpp
@@ -46,6 +46,8 @@
     "Usage: ndnsec cert-gen [-h] [-S TIMESTAMP] [-E TIMESTAMP] [-I INFO]...\n"
     "                       [-s IDENTITY] [-i ISSUER] [-r] FILE\n"
     "\n"
+    "Issue a certificate from a certificate signing request.\n"
+    "\n"
     "Options");
   description.add_options()
     ("help,h", "produce help message")
diff --git a/tools/ndnsec/cert-install.cpp b/tools/ndnsec/cert-install.cpp
index 345ee24..f7ce2f0 100644
--- a/tools/ndnsec/cert-install.cpp
+++ b/tools/ndnsec/cert-install.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2023 Regents of the University of California.
+ * Copyright (c) 2013-2024 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -42,6 +42,8 @@
   po::options_description description(
     "Usage: ndnsec cert-install [-h] [-I|-K|-N] [-f] FILE\n"
     "\n"
+    "Import a certificate from a file.\n"
+    "\n"
     "Options");
   description.add_options()
     ("help,h", "produce help message")
diff --git a/tools/ndnsec/delete.cpp b/tools/ndnsec/delete.cpp
index 25de41c..4b19892 100644
--- a/tools/ndnsec/delete.cpp
+++ b/tools/ndnsec/delete.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2023 Regents of the University of California.
+ * Copyright (c) 2013-2024 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -36,6 +36,8 @@
   po::options_description description(
     "Usage: ndnsec delete [-h] [-k|-c] [-n] NAME\n"
     "\n"
+    "Delete an identity, key, or certificate.\n"
+    "\n"
     "Options");
   description.add_options()
     ("help,h", "produce help message")
diff --git a/tools/ndnsec/export.cpp b/tools/ndnsec/export.cpp
index 5641e08..0350bac 100644
--- a/tools/ndnsec/export.cpp
+++ b/tools/ndnsec/export.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2023 Regents of the University of California.
+ * Copyright (c) 2013-2024 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -47,6 +47,8 @@
   po::options_description visibleOptDesc(
     "Usage: ndnsec export [-h] [-o FILE] [-P PASSPHRASE] [-i|-k|-c] NAME\n"
     "\n"
+    "Export a private key and its certificate in SafeBag format.\n"
+    "\n"
     "Options");
   visibleOptDesc.add_options()
     ("help,h", "produce help message")
diff --git a/tools/ndnsec/get-default.cpp b/tools/ndnsec/get-default.cpp
index 8dba1bf..3d3a7f2 100644
--- a/tools/ndnsec/get-default.cpp
+++ b/tools/ndnsec/get-default.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2023 Regents of the University of California.
+ * Copyright (c) 2013-2024 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -38,6 +38,8 @@
   po::options_description description(
     "Usage: ndnsec get-default [-h] [-k|-c] [-i ID|-K KEY] [-q]\n"
     "\n"
+    "Show the default identity, key, or certificate.\n"
+    "\n"
     "Options");
   description.add_options()
     ("help,h", "produce help message")
diff --git a/tools/ndnsec/import.cpp b/tools/ndnsec/import.cpp
index 9e0c830..98a4c50 100644
--- a/tools/ndnsec/import.cpp
+++ b/tools/ndnsec/import.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2023 Regents of the University of California.
+ * Copyright (c) 2013-2024 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -43,6 +43,8 @@
   po::options_description description(
     "Usage: ndnsec import [-h] [-P PASSPHRASE] [-i] FILE\n"
     "\n"
+    "Import a private key and its certificate from a SafeBag.\n"
+    "\n"
     "Options");
   description.add_options()
     ("help,h", "produce help message")
diff --git a/tools/ndnsec/key-gen.cpp b/tools/ndnsec/key-gen.cpp
index bd3712e..77c7d57 100644
--- a/tools/ndnsec/key-gen.cpp
+++ b/tools/ndnsec/key-gen.cpp
@@ -36,7 +36,10 @@
   std::string userKeyId;
 
   po::options_description description(
-    "Usage: ndnsec key-gen [-h] [-n] [-t TYPE] [-k KEYIDTYPE|--keyid KEYID] [-i] IDENTITY\n"
+    "Usage: ndnsec key-gen [-h] [-n] [-t TYPE] [-k KEYIDTYPE|--keyid KEYID]\n"
+    "                      [-i] IDENTITY\n"
+    "\n"
+    "Generate a public/private key pair for an identity.\n"
     "\n"
     "Options");
   description.add_options()
diff --git a/tools/ndnsec/list.cpp b/tools/ndnsec/list.cpp
index 3b02b80..201ffbb 100644
--- a/tools/ndnsec/list.cpp
+++ b/tools/ndnsec/list.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2023 Regents of the University of California.
+ * Copyright (c) 2013-2024 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -208,6 +208,8 @@
   po::options_description description(
     "Usage: ndnsec list [-h] [-k] [-c] [-v]\n"
     "\n"
+    "List all known identities, keys, and certificates.\n"
+    "\n"
     "Options");
   description.add_options()
     ("help,h", "produce help message")
diff --git a/tools/ndnsec/main.cpp b/tools/ndnsec/main.cpp
index aa6ce37..a9a055b 100644
--- a/tools/ndnsec/main.cpp
+++ b/tools/ndnsec/main.cpp
@@ -35,14 +35,14 @@
 
 Available commands:
   help           Print this help text
-  list           List all known identities/keys/certificates
-  get-default    Show the default identity/key/certificate
-  set-default    Change the default identity/key/certificate
-  delete         Delete an identity/key/certificate
-  key-gen        Generate a key for an identity
+  list           List all known identities, keys, and certificates
+  get-default    Show the default identity, key, or certificate
+  set-default    Change the default identity, key, or certificate
+  delete         Delete an identity, key, or certificate
+  key-gen        Generate a key pair for an identity
   sign-req       Generate a certificate signing request
-  cert-gen       Create a certificate for an identity
-  cert-dump      Export a certificate
+  cert-gen       Issue a certificate for an identity
+  cert-dump      Display a certificate
   cert-install   Import a certificate from a file
   export         Export an identity as a SafeBag
   import         Import an identity from a SafeBag
diff --git a/tools/ndnsec/set-default.cpp b/tools/ndnsec/set-default.cpp
index b0ebf09..f78d23e 100644
--- a/tools/ndnsec/set-default.cpp
+++ b/tools/ndnsec/set-default.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2023 Regents of the University of California.
+ * Copyright (c) 2013-2024 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -36,6 +36,8 @@
   po::options_description description(
     "Usage: ndnsec set-default [-h] [-k|-c] [-n] NAME\n"
     "\n"
+    "Change the default identity, key, or certificate.\n"
+    "\n"
     "Options");
   description.add_options()
     ("help,h", "produce help message")
diff --git a/tools/ndnsec/sign-req.cpp b/tools/ndnsec/sign-req.cpp
index 2023ce9..f3f714f 100644
--- a/tools/ndnsec/sign-req.cpp
+++ b/tools/ndnsec/sign-req.cpp
@@ -37,6 +37,8 @@
   po::options_description description(
     "Usage: ndnsec sign-req [-h] [-k] [-n] NAME\n"
     "\n"
+    "Generate a certificate signing request.\n"
+    "\n"
     "Options");
   description.add_options()
     ("help,h", "produce help message")