diff --git a/libopenfpga/libopenfpgashell/src/command.cpp b/libopenfpga/libopenfpgashell/src/command.cpp
index fb79c5259..8c20ffe5a 100644
--- a/libopenfpga/libopenfpgashell/src/command.cpp
+++ b/libopenfpga/libopenfpgashell/src/command.cpp
@@ -4,8 +4,8 @@
 #include "vtr_assert.h"
 #include "command.h"
 
-/* Begin namespace minishell */
-namespace minishell {
+/* Begin namespace openfpga */
+namespace openfpga {
 
 /*********************************************************************
  * Public constructors
@@ -169,4 +169,4 @@ bool Command::valid_option_id(const CommandOptionId& option_id) const {
   return ( size_t(option_id) < option_ids_.size() ) && ( option_id == option_ids_[option_id] ); 
 }
 
-} /* End namespace minshell */
+} /* End namespace openfpga */
diff --git a/libopenfpga/libopenfpgashell/src/command.h b/libopenfpga/libopenfpgashell/src/command.h
index c4a1b9869..05bf89fed 100644
--- a/libopenfpga/libopenfpgashell/src/command.h
+++ b/libopenfpga/libopenfpgashell/src/command.h
@@ -23,8 +23,8 @@
 #include "vtr_range.h"
 #include "command_fwd.h"
 
-/* Begin namespace minishell */
-namespace minishell {
+/* Begin namespace openfpga */
+namespace openfpga {
 
 /*********************************************************************
  * Supported date types of value which is followed by a command-line option
@@ -139,6 +139,6 @@ class Command {
     std::map<std::string, CommandOptionId> option_short_name2ids_;
 };
 
-} /* End namespace minshell */
+} /* End namespace openfpga */
 
 #endif
diff --git a/libopenfpga/libopenfpgashell/src/command_context.cpp b/libopenfpga/libopenfpgashell/src/command_context.cpp
index 30f9992ad..ee7c684d6 100644
--- a/libopenfpga/libopenfpgashell/src/command_context.cpp
+++ b/libopenfpga/libopenfpgashell/src/command_context.cpp
@@ -4,8 +4,8 @@
 #include "vtr_assert.h"
 #include "command_context.h"
 
-/* Begin namespace minishell */
-namespace minishell {
+/* Begin namespace openfpga */
+namespace openfpga {
 
 /*********************************************************************
  * Public constructor
@@ -66,4 +66,4 @@ void CommandContext::set_option_value(const Command& command,
   option_values_[option_id] = value;
 }
 
-} /* End namespace minshell */
+} /* End namespace openfpga */
diff --git a/libopenfpga/libopenfpgashell/src/command_context.h b/libopenfpga/libopenfpgashell/src/command_context.h
index fb983218e..2300888cf 100644
--- a/libopenfpga/libopenfpgashell/src/command_context.h
+++ b/libopenfpga/libopenfpgashell/src/command_context.h
@@ -6,8 +6,8 @@
 #include "command_fwd.h"
 #include "command.h"
 
-/* Begin namespace minishell */
-namespace minishell {
+/* Begin namespace openfpga */
+namespace openfpga {
 
 /*********************************************************************
  * Data structure to stores parsing results for a command
@@ -54,6 +54,6 @@ class CommandContext {
     vtr::vector<CommandOptionId, std::string> option_values_;  
 };
 
-} /* End namespace minshell */
+} /* End namespace openfpga */
 
 #endif
diff --git a/libopenfpga/libopenfpgashell/src/command_echo.cpp b/libopenfpga/libopenfpgashell/src/command_echo.cpp
index 78fc9aabb..c9d930dc8 100644
--- a/libopenfpga/libopenfpgashell/src/command_echo.cpp
+++ b/libopenfpga/libopenfpgashell/src/command_echo.cpp
@@ -6,18 +6,18 @@
 #include "vtr_log.h"
 #include "command_echo.h"
 
-/* Begin namespace minishell */
-namespace minishell {
+/* Begin namespace openfpga */
+namespace openfpga {
 
 /*********************************************************************
  * Print all the options that are defined in an object Command
  * This function is mainly used to create help desk for a command
  ********************************************************************/
 void print_command_options(const Command& cmd) {
-  VTR_LOG("Command '%s' usage:\n",
-          cmd.name().c_str());
+  VTR_LOG("Command '%s' usage:\n%lu options available\n",
+          cmd.name().c_str(), cmd.options().size());
   for (const CommandOptionId& opt : cmd.options()) {
-    VTR_LOG("--%s, -%s : %s\n",
+    VTR_LOG("\t--%s, -%s : %s\n",
             cmd.option_name(opt).c_str(),
             cmd.option_short_name(opt).c_str(),
             cmd.option_description(opt).c_str());
diff --git a/libopenfpga/libopenfpgashell/src/command_echo.h b/libopenfpga/libopenfpgashell/src/command_echo.h
index eb3923100..2d8ce2c66 100644
--- a/libopenfpga/libopenfpgashell/src/command_echo.h
+++ b/libopenfpga/libopenfpgashell/src/command_echo.h
@@ -11,14 +11,14 @@
  * Function declaration
  *******************************************************************/
 
-/* Begin namespace minishell */
-namespace minishell {
+/* Begin namespace openfpga */
+namespace openfpga {
 
 void print_command_options(const Command& cmd);
 
 void print_command_context(const Command& cmd, 
                            const CommandContext& cmd_context);
 
-} /* End namespace minshell */
+} /* End namespace openfpga */
 
 #endif
diff --git a/libopenfpga/libopenfpgashell/src/command_fwd.h b/libopenfpga/libopenfpgashell/src/command_fwd.h
index 52dd81d65..3d59097dc 100644
--- a/libopenfpga/libopenfpgashell/src/command_fwd.h
+++ b/libopenfpga/libopenfpgashell/src/command_fwd.h
@@ -3,8 +3,8 @@
 
 #include "vtr_strong_id.h"
 
-/* Begin namespace minishell */
-namespace minishell {
+/* Begin namespace openfpga */
+namespace openfpga {
 
 /*********************************************************************
  * A strong id for the options used by a command 
@@ -13,6 +13,6 @@ struct command_option_id_tag;
 
 typedef vtr::StrongId<command_option_id_tag> CommandOptionId;
 
-} /* End namespace minshell */
+} /* End namespace openfpga */
 
 #endif
diff --git a/libopenfpga/libopenfpgashell/src/command_parser.cpp b/libopenfpga/libopenfpgashell/src/command_parser.cpp
index 057660e2e..5e0397421 100644
--- a/libopenfpga/libopenfpgashell/src/command_parser.cpp
+++ b/libopenfpga/libopenfpgashell/src/command_parser.cpp
@@ -10,8 +10,8 @@
 #include "vtr_log.h"
 #include "command_parser.h"
 
-/* Begin namespace minishell */
-namespace minishell {
+/* Begin namespace openfpga */
+namespace openfpga {
 
 /********************************************************************
  * Try to find an option in the command and update the CommandContext if needed
@@ -25,6 +25,7 @@ CommandOptionId parse_option(const std::string& argv,
   if (CommandOptionId::INVALID() == option_id) {
     VTR_LOG("Detect unknown option '--%s'!\n",
             argv.c_str());
+    return CommandOptionId::INVALID();
   }
   /* Found, update the CommandContext */
   cmd_context.set_option(cmd, option_id, true);
@@ -45,6 +46,7 @@ CommandOptionId parse_short_option(const std::string& argv,
   if (CommandOptionId::INVALID() == option_id) {
     VTR_LOG("Detect unknown short option '-%s'!\n",
             argv.c_str());
+    return CommandOptionId::INVALID();
   }
   /* Found, update the CommandContext */
   cmd_context.set_option(cmd, option_id, true);
@@ -160,4 +162,4 @@ bool parse_command(const std::vector<std::string>& argv,
   return true;
 }
 
-} /* End namespace minshell */
+} /* End namespace openfpga */
diff --git a/libopenfpga/libopenfpgashell/src/command_parser.h b/libopenfpga/libopenfpgashell/src/command_parser.h
index 6aee4291b..568bb7ffc 100644
--- a/libopenfpga/libopenfpgashell/src/command_parser.h
+++ b/libopenfpga/libopenfpgashell/src/command_parser.h
@@ -12,13 +12,13 @@
  * Function declaration
  *******************************************************************/
 
-/* Begin namespace minishell */
-namespace minishell {
+/* Begin namespace openfpga */
+namespace openfpga {
 
 bool parse_command(const std::vector<std::string>& argv,
                    const Command& cmd,
                    CommandContext& cmd_context);
 
-} /* End namespace minshell */
+} /* End namespace openfpga */
 
 #endif
diff --git a/libopenfpga/libopenfpgashell/src/shell.h b/libopenfpga/libopenfpgashell/src/shell.h
index 2c64381a4..0f83b4e46 100644
--- a/libopenfpga/libopenfpgashell/src/shell.h
+++ b/libopenfpga/libopenfpgashell/src/shell.h
@@ -12,8 +12,8 @@
 #include "command_context.h"
 #include "shell_fwd.h"
 
-/* Begin namespace minishell */
-namespace minishell {
+/* Begin namespace openfpga */
+namespace openfpga {
 
 /*********************************************************************
  * Data structure to define a working environment of a mini shell
@@ -171,7 +171,7 @@ class Shell {
     vtr::vector<ShellCommandClassId, std::vector<ShellCommandId>> commands_by_classes_;  
 };
 
-} /* End namespace minshell */
+} /* End namespace openfpga */
 
 /* Include the template implementation functions in the header file */
 #include "shell.tpp"
diff --git a/libopenfpga/libopenfpgashell/src/shell.tpp b/libopenfpga/libopenfpgashell/src/shell.tpp
index 809c3c59a..00b70ffed 100644
--- a/libopenfpga/libopenfpgashell/src/shell.tpp
+++ b/libopenfpga/libopenfpgashell/src/shell.tpp
@@ -19,8 +19,8 @@
 #include "command_parser.h"
 #include "command_echo.h"
 
-/* Begin namespace minishell */
-namespace minishell {
+/* Begin namespace openfpga */
+namespace openfpga {
 
 /*********************************************************************
  * Public constructors
@@ -380,4 +380,4 @@ bool Shell<T>::valid_command_class_id(const ShellCommandClassId& cmd_class_id) c
   return ( size_t(cmd_class_id) < command_class_ids_.size() ) && ( cmd_class_id == command_class_ids_[cmd_class_id] ); 
 }
 
-} /* End namespace minshell */
+} /* End namespace openfpga */
diff --git a/libopenfpga/libopenfpgashell/src/shell_fwd.h b/libopenfpga/libopenfpgashell/src/shell_fwd.h
index cea5c70e2..5a1557210 100644
--- a/libopenfpga/libopenfpgashell/src/shell_fwd.h
+++ b/libopenfpga/libopenfpgashell/src/shell_fwd.h
@@ -3,8 +3,8 @@
 
 #include "vtr_strong_id.h"
 
-/* Begin namespace minishell */
-namespace minishell {
+/* Begin namespace openfpga */
+namespace openfpga {
 
 /*********************************************************************
  * A strong id for the options used by a command 
@@ -15,6 +15,6 @@ struct shell_command_class_id_tag;
 typedef vtr::StrongId<shell_command_id_tag> ShellCommandId;
 typedef vtr::StrongId<shell_command_class_id_tag> ShellCommandClassId;
 
-} /* End namespace minshell */
+} /* End namespace openfpga */
 
 #endif
diff --git a/libopenfpga/libopenfpgashell/test/test_command_parser.cpp b/libopenfpga/libopenfpgashell/test/test_command_parser.cpp
index 2d18765a7..c3e004137 100644
--- a/libopenfpga/libopenfpgashell/test/test_command_parser.cpp
+++ b/libopenfpga/libopenfpgashell/test/test_command_parser.cpp
@@ -4,7 +4,7 @@
 #include "command_parser.h"
 #include "command_echo.h"
 
-using namespace minishell;
+using namespace openfpga;
 
 int main(int argc, char** argv) {
   /* Create a new command */
diff --git a/libopenfpga/libopenfpgashell/test/test_shell.cpp b/libopenfpga/libopenfpgashell/test/test_shell.cpp
index 24099fc9b..8fc00f055 100644
--- a/libopenfpga/libopenfpgashell/test/test_shell.cpp
+++ b/libopenfpga/libopenfpgashell/test/test_shell.cpp
@@ -7,11 +7,26 @@
 #include "command_echo.h"
 #include "shell.h"
 
-using namespace minishell;
+using namespace openfpga;
 
 class ShellContext {
+  public:
+    int a;
 };
 
+static
+void shell_execute_set(ShellContext& context, 
+                       const Command& cmd, const CommandContext& cmd_context) {
+  CommandOptionId opt_id = cmd.option("value");
+  /* Get the value of a in the command context */
+  context.a = std::atoi(cmd_context.option_value(cmd, opt_id).c_str());
+}
+
+static
+void shell_execute_print(ShellContext& context) {
+  VTR_LOG("a=%d\n", context.a);
+}
+
 int main(int argc, char** argv) {
   /* Create the command to launch shell in different modes */
   Command start_cmd("test_shell");
@@ -61,6 +76,27 @@ int main(int argc, char** argv) {
 
   shell.add_title(shell_title.c_str());
 
+  /* Add a new class of commands */
+  ShellCommandClassId arith_cmd_class = shell.add_command_class("Arithmetic");
+
+  /* Create a command of 'set' with a required option 'value' with a value 
+   * This function sets a value to an internal variable of ShellContext 
+   */
+  Command shell_cmd_set("set");
+  CommandOptionId set_opt_value = shell_cmd_set.add_option("value", true, "value of variable");
+  shell_cmd_set.set_option_require_value(set_opt_value, OPT_STRING);
+  ShellCommandId shell_cmd_set_id = shell.add_command(shell_cmd_set, "Set a value to internal variable 'a'");
+  shell.set_command_class(shell_cmd_set_id, arith_cmd_class);
+  shell.set_command_execute_function(shell_cmd_set_id, shell_execute_set);
+
+  /* Create a command of 'print' 
+   * This function will print the value of an internal variable of ShellContext 
+   */
+  Command shell_cmd_print("print");
+  ShellCommandId shell_cmd_print_id = shell.add_command(shell_cmd_print, "Print the value of internal variable 'a'");
+  shell.set_command_class(shell_cmd_print_id, arith_cmd_class);
+  shell.set_command_execute_function(shell_cmd_print_id, shell_execute_print);
+
   /* Add a new class of commands */
   ShellCommandClassId basic_cmd_class = shell.add_command_class("Basic");