diff --git a/CMakeLists.txt b/CMakeLists.txt
index 31eaf18d6..3e92ccc68 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -209,6 +209,18 @@ foreach(EACH IN LISTS ${PROJECT_NAME}_TEST_CPP)
             ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/test_${FILENAME})
 endforeach()
 
+file(GLOB ${PROJECT_NAME}_TEST_SH ${CMAKE_CURRENT_SOURCE_DIR}/test/*.sh)
+
+foreach(EACH IN LISTS ${PROJECT_NAME}_TEST_SH)
+  get_filename_component(FILENAME ${EACH} NAME_WE)
+  add_test(
+    NAME ${FILENAME}
+    COMMAND ${${PROJECT_NAME}_MEMORY_CHECK_COMMAND}
+            ${${PROJECT_NAME}_MEMORY_CHECK_OPTIONS}
+            ${EACH}
+            ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/meevax)
+endforeach()
+
 # ---- Additional Targets ------------------------------------------------------
 
 execute_process(COMMAND nproc OUTPUT_VARIABLE ${PROJECT_NAME}_NPROC)
diff --git a/README.md b/README.md
index f13fbd235..23e4fc726 100644
--- a/README.md
+++ b/README.md
@@ -90,7 +90,7 @@ Procedures for each standard are provided by the following R7RS-style libraries:
 cmake -B build -DCMAKE_BUILD_TYPE=Release
 cd build
 make package
-sudo apt install build/meevax_0.5.190_amd64.deb
+sudo apt install build/meevax_0.5.191_amd64.deb
 ```
 
 or
@@ -122,9 +122,9 @@ sudo rm -rf /usr/local/share/meevax
 
 | Target Name | Description
 |-------------|-------------
-| `all`       | Build shared-library `libmeevax.0.5.190.so` and executable `meevax`
+| `all`       | Build shared-library `libmeevax.0.5.191.so` and executable `meevax`
 | `test`      | Test executable `meevax`
-| `package`   | Generate debian package `meevax_0.5.190_amd64.deb`
+| `package`   | Generate debian package `meevax_0.5.191_amd64.deb`
 | `install`   | Copy files into `/usr/local` directly
 
 ## Usage
diff --git a/VERSION b/VERSION
index a81dc9010..d1f514113 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.5.190
+0.5.191
diff --git a/include/meevax/kernel/configurator.hpp b/include/meevax/kernel/configurator.hpp
index 6ad24186f..252456a71 100644
--- a/include/meevax/kernel/configurator.hpp
+++ b/include/meevax/kernel/configurator.hpp
@@ -35,12 +35,12 @@ inline namespace kernel
     {
       std::regex const pattern;
 
-      std::function<object (std::function<object ()> const&)> build;
+      std::function<auto (std::function<auto () -> object> const&) -> void> evaluate;
 
       template <typename S, typename F>
       explicit option(S&& s, F&& f)
-        : pattern { std::forward<decltype(s)>(s) }
-        , build   { std::forward<decltype(f)>(f) }
+        : pattern  { std::forward<decltype(s)>(s) }
+        , evaluate { std::forward<decltype(f)>(f) }
       {}
     };
 
@@ -60,71 +60,44 @@ inline namespace kernel
 
     auto configure(std::vector<std::string> const& args) -> void
     {
-      static auto const pattern = std::regex(R"(--(\w[-\w]+)(=(.*))?|-([\w]+))");
+      auto const static pattern = std::regex(R"(--(\w[-\w]+)(=(.*))?|-([\w]+))");
 
-      auto const options = std::vector<option>
+      auto const options = std::array<option, 6>
       {
         option("(i|interactive)", [this](auto)
         {
-          let const f = make<procedure>(__func__, [this](let const&)
-          {
-            interactive = true;
-            return unspecified;
-          });
-
-          return list(f);
+          interactive = true;
         }),
 
-        option("(e|evaluate)", [](auto read)
+        option("(e|evaluate)", [this](auto read)
         {
-          return read();
+          static_cast<Environment &>(*this).evaluate(read());
         }),
 
         option("(h|help)", [](auto)
         {
-          let static const f = make<procedure>(__func__, [](let const&)
-          {
-            std::cout << help() << std::endl;
-            throw EXIT_SUCCESS;
-          });
-
-          return list(f);
+          std::cout << help() << std::endl;
+          throw EXIT_SUCCESS;
         }),
 
         option("(l|load)", [this](auto read)
         {
-          let const f = make<procedure>(__func__, [this](let const& xs)
-          {
-            static_cast<Environment &>(*this).load(car(xs).as<string>());
-            return unspecified;
-          });
-
-          return list(f, read());
+          static_cast<Environment &>(*this).load(read().template as<string>());
         }),
 
         option("(v|version)", [](auto)
         {
-          let static const f = make<procedure>(__func__, [](let const&)
-          {
-            std::cout << version() << std::endl;
-            throw EXIT_SUCCESS;
-          });
-
-          return list(f);
+          std::cout << version() << std::endl;
+          throw EXIT_SUCCESS;
         }),
 
         option("(w|write)", [](auto read)
         {
-          let static const f = make<procedure>(__func__, [](let const& xs)
-          {
-            std::cout << car(xs) << std::endl;
-          });
-
-          return list(f, read());
+          std::cout << read() << std::endl;
         }),
       };
 
-      auto search = [&](auto&& name) -> decltype(auto)
+      auto evaluator = [&](auto&& name) -> decltype(auto)
       {
         if (auto iter = std::find_if(options.begin(), options.end(), [&](auto&& option)
                         {
@@ -132,7 +105,7 @@ inline namespace kernel
                         });
             iter != options.end())
         {
-          return *iter;
+          return iter->evaluate;
         }
         else
         {
@@ -140,8 +113,6 @@ inline namespace kernel
         }
       };
 
-      std::vector<object> expressions {};
-
       for (auto iter = std::next(args.begin()); iter != args.end(); ++iter)
       {
         static std::regex const pattern { R"(--(\w[-\w]+)(?:=(.*))?|-([\w]+))" };
@@ -165,39 +136,26 @@ inline namespace kernel
           {
             for (auto str3 = result.str(3); not str3.empty(); str3.erase(0, 1))
             {
-              expressions.push_back(search(str3.substr(0, 1)).build(read));
+              std::invoke(evaluator(str3.substr(0, 1)), read);
             }
           }
           else if (result.length(2))
           {
-            auto read = [result]()
+            std::invoke(evaluator(result.str(1)), [result]()
             {
               return input_string_port(result.str(2)).read();
-            };
-
-            expressions.push_back(search(result.str(1)).build(read));
+            });
           }
           else if (result.length(1))
           {
-            expressions.push_back(search(result.str(1)).build(read));
+            std::invoke(evaluator(result.str(1)), read);
           }
         }
         else
         {
-          let const f = make<procedure>(__func__, [iter](let const&)
-          {
-            Environment().load(*iter);
-            return unspecified;
-          });
-
-          expressions.push_back(list(f));
+          Environment().load(*iter);
         }
       }
-
-      for (let const& expression : expressions)
-      {
-        static_cast<Environment &>(*this).evaluate(expression);
-      }
     }
   };
 } // namespace kernel
diff --git a/include/meevax/kernel/error.hpp b/include/meevax/kernel/error.hpp
index d69342f18..e83c66a61 100644
--- a/include/meevax/kernel/error.hpp
+++ b/include/meevax/kernel/error.hpp
@@ -38,7 +38,7 @@ inline namespace kernel
 
     std::vector<detail> details {};
 
-    mutable std::string brief {};
+    mutable std::string explanation {};
 
     using pair::pair;
 
@@ -108,7 +108,7 @@ inline namespace kernel
     }
     catch (std::exception const& exception)
     {
-      std::cerr << error(make<string>(exception.what())) << std::endl;
+      error(make<string>(exception.what())).report(std::cerr);
       return EXIT_FAILURE;
     }
   }
diff --git a/src/kernel/error.cpp b/src/kernel/error.cpp
index b37d9db96..0e107542b 100644
--- a/src/kernel/error.cpp
+++ b/src/kernel/error.cpp
@@ -53,7 +53,7 @@ inline namespace kernel
   {
     try
     {
-      if (brief.empty())
+      if (explanation.empty())
       {
         auto output = std::stringstream();
 
@@ -64,10 +64,10 @@ inline namespace kernel
           output << ": " << irritants();
         }
 
-        brief = output.str();
+        explanation = output.str();
       }
 
-      return brief.c_str();
+      return explanation.c_str();
     }
     catch (...)
     {
diff --git a/test/option.sh b/test/option.sh
new file mode 100755
index 000000000..221e3a687
--- /dev/null
+++ b/test/option.sh
@@ -0,0 +1,8 @@
+#!/bin/sh
+
+meevax=$1
+
+$meevax -e '(import (scheme base))' -e '(+ 1 2 3)'
+$meevax -h
+$meevax -v
+$meevax -w '(+ 1 2 3)'