diff --git a/bootstrap/src/build_buildcc.cpp b/bootstrap/src/build_buildcc.cpp
index 7432964a..f8ae45e5 100644
--- a/bootstrap/src/build_buildcc.cpp
+++ b/bootstrap/src/build_buildcc.cpp
@@ -53,11 +53,6 @@ void buildcc_cb(BaseTarget &target, const BaseGenerator &schema_gen,
   target.AddIncludeDir("lib/env/include");
   target.GlobHeaders("lib/env/include/env");
 
-  // COMMAND
-  target.GlobSources("lib/command/src");
-  target.AddIncludeDir("lib/command/include");
-  target.GlobHeaders("lib/command/include/command");
-
   // TOOLCHAIN
   target.AddIncludeDir("lib/toolchain/include");
   target.GlobHeaders("lib/toolchain/include/toolchain");
diff --git a/buildcc/CMakeLists.txt b/buildcc/CMakeLists.txt
index 90bf1a23..860404be 100644
--- a/buildcc/CMakeLists.txt
+++ b/buildcc/CMakeLists.txt
@@ -34,9 +34,6 @@ endif()
 # Environment
 add_subdirectory(lib/env)
 
-# 
-add_subdirectory(lib/command)
-
 # Toolchain
 add_subdirectory(lib/toolchain)
 add_subdirectory(toolchains)
diff --git a/buildcc/buildcc.h b/buildcc/buildcc.h
index 8e533a96..84861233 100644
--- a/buildcc/buildcc.h
+++ b/buildcc/buildcc.h
@@ -26,9 +26,7 @@
 #include "env/host_os.h"
 #include "env/host_compiler.h"
 #include "env/util.h"
-
-// 
-#include "command/command.h"
+#include "env/command.h"
 
 // Base
 #include "toolchain/toolchain.h"
diff --git a/buildcc/lib/args/src/register.cpp b/buildcc/lib/args/src/register.cpp
index c6a02173..4ea1ed9e 100644
--- a/buildcc/lib/args/src/register.cpp
+++ b/buildcc/lib/args/src/register.cpp
@@ -129,7 +129,7 @@ void Register::Env() {
 void TestInfo::TestRunner() const {
   env::log_info(__FUNCTION__,
                 fmt::format("Testing \'{}\'", target_.GetUniqueId()));
-  Command command;
+  env::Command command;
   command.AddDefaultArguments({
       {"executable", fmt::format("{}", target_.GetTargetPath())},
   });
@@ -173,8 +173,8 @@ void TestInfo::TestRunner() const {
   };
 
   const bool success =
-      Command::Execute(test_command, config_.GetWorkingDirectory(),
-                       redirect_stdout, redirect_stderr);
+      env::Command::Execute(test_command, config_.GetWorkingDirectory(),
+                            redirect_stdout, redirect_stderr);
   env::assert_fatal(success,
                     fmt::format("Could not run {}", target_.GetUniqueId()));
 
diff --git a/buildcc/lib/args/src/tasks.cpp b/buildcc/lib/args/src/tasks.cpp
index b459007f..a0068999 100644
--- a/buildcc/lib/args/src/tasks.cpp
+++ b/buildcc/lib/args/src/tasks.cpp
@@ -16,6 +16,7 @@
 
 #include "args/register.h"
 #include "env/logging.h"
+#include "env/util.h"
 
 namespace buildcc {
 
@@ -33,6 +34,8 @@ void Register::RunBuild() {
                                           executor_.num_workers()));
   executor_.run(build_tf_);
   executor_.wait_for_all();
+  env::assert_fatal(env::get_task_state() == env::TaskState::SUCCESS,
+                    "Task state is not successful!");
 }
 
 void Register::RunTest() {
diff --git a/buildcc/lib/args/test/test_register.cpp b/buildcc/lib/args/test/test_register.cpp
index a4d58e95..e68d7fa6 100644
--- a/buildcc/lib/args/test/test_register.cpp
+++ b/buildcc/lib/args/test/test_register.cpp
@@ -535,7 +535,7 @@ TEST(RegisterTestGroup, Register_Test) {
 
     std::vector<std::string> stdout_data;
     std::vector<std::string> stderr_data;
-    buildcc::m::CommandExpect_Execute(1, true, &stdout_data, &stderr_data);
+    buildcc::env::m::CommandExpect_Execute(1, true, &stdout_data, &stderr_data);
     reg.RunTest();
   }
 
@@ -588,7 +588,7 @@ TEST(RegisterTestGroup, Register_TestWithOutput) {
             {}, {},
             buildcc::TestOutput(buildcc::TestOutput::Type::DefaultBehaviour)));
 
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     reg.RunTest();
   }
 
@@ -606,7 +606,7 @@ TEST(RegisterTestGroup, Register_TestWithOutput) {
             buildcc::TestOutput(buildcc::TestOutput::Type::TestPrintOnStderr)));
 
     std::vector<std::string> stderr_data;
-    buildcc::m::CommandExpect_Execute(1, true, nullptr, &stderr_data);
+    buildcc::env::m::CommandExpect_Execute(1, true, nullptr, &stderr_data);
     reg.RunTest();
   }
 
@@ -624,7 +624,7 @@ TEST(RegisterTestGroup, Register_TestWithOutput) {
             buildcc::TestOutput(buildcc::TestOutput::Type::TestPrintOnStdout)));
 
     std::vector<std::string> stdout_data;
-    buildcc::m::CommandExpect_Execute(1, true, &stdout_data, nullptr);
+    buildcc::env::m::CommandExpect_Execute(1, true, &stdout_data, nullptr);
     reg.RunTest();
   }
 
@@ -643,7 +643,7 @@ TEST(RegisterTestGroup, Register_TestWithOutput) {
 
     std::vector<std::string> stdout_data;
     std::vector<std::string> stderr_data;
-    buildcc::m::CommandExpect_Execute(1, true, &stdout_data, &stderr_data);
+    buildcc::env::m::CommandExpect_Execute(1, true, &stdout_data, &stderr_data);
     reg.RunTest();
   }
 
@@ -660,7 +660,7 @@ TEST(RegisterTestGroup, Register_TestWithOutput) {
                  buildcc::TestOutput(buildcc::TestOutput::Type::UserRedirect,
                                      nullptr, nullptr)));
 
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     reg.RunTest();
   }
 
@@ -684,7 +684,7 @@ TEST(RegisterTestGroup, Register_TestWithOutput) {
 
 int main(int ac, char **av) {
   MemoryLeakWarningPlugin::turnOffNewDeleteOverloads();
-  buildcc::m::VectorStringCopier copier;
+  buildcc::env::m::VectorStringCopier copier;
   mock().installCopier(TEST_VECTOR_STRING_TYPE, copier);
   return CommandLineTestRunner::RunAllTests(ac, av);
 }
diff --git a/buildcc/lib/command/CMakeLists.txt b/buildcc/lib/command/CMakeLists.txt
deleted file mode 100644
index 307428cc..00000000
--- a/buildcc/lib/command/CMakeLists.txt
+++ /dev/null
@@ -1,68 +0,0 @@
-if (${TESTING})
-    add_library(mock_command
-        mock/execute.cpp
-        src/command.cpp
-    )
-    target_include_directories(mock_command PUBLIC 
-        ${CMAKE_CURRENT_SOURCE_DIR}/include
-        ${CMAKE_CURRENT_SOURCE_DIR}/mock
-    )
-    target_link_libraries(mock_command PUBLIC
-        fmt::fmt-header-only
-        mock_env
-        CppUTest
-        CppUTestExt
-        gcov
-    )
-    target_compile_options(mock_command PUBLIC ${TEST_COMPILE_FLAGS} ${BUILD_COMPILE_FLAGS})
-    target_link_options(mock_command PUBLIC ${TEST_LINK_FLAGS} ${BUILD_LINK_FLAGS})
-
-    # Tests
-    add_executable(test_command test/test_command.cpp)
-    target_link_libraries(test_command PRIVATE mock_command)
-    
-    add_test(NAME test_command COMMAND test_command)
-endif()
-
-set(COMMAND_SRCS
-    src/execute.cpp
-    src/command.cpp
-    include/command/command.h
-)
-
-if(${BUILDCC_BUILD_AS_SINGLE_LIB})
-    target_sources(buildcc PRIVATE
-        ${COMMAND_SRCS}
-    )
-    target_include_directories(buildcc PUBLIC
-        $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
-        $<INSTALL_INTERFACE:${BUILDCC_INSTALL_HEADER_PREFIX}>
-    )
-endif()
-
-if(${BUILDCC_BUILD_AS_INTERFACE})
-    m_clangtidy("command")
-    add_library(command
-        ${COMMAND_SRCS}
-    )
-    target_include_directories(command PUBLIC 
-        $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
-        $<INSTALL_INTERFACE:${BUILDCC_INSTALL_HEADER_PREFIX}>
-    )
-    target_link_libraries(command PRIVATE 
-        fmt::fmt-header-only
-        tiny-process-library::tiny-process-library
-
-        env
-    )
-    target_compile_options(command PRIVATE ${BUILD_COMPILE_FLAGS})
-    target_link_options(command PRIVATE ${BUILD_LINK_FLAGS})
-endif()
-
-if (${BUILDCC_INSTALL})
-    if(${BUILDCC_BUILD_AS_INTERFACE})
-        install(TARGETS command DESTINATION lib EXPORT commandConfig)
-        install(EXPORT commandConfig DESTINATION "${BUILDCC_INSTALL_LIB_PREFIX}/command")
-    endif()
-    install(DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/include/ DESTINATION "${BUILDCC_INSTALL_HEADER_PREFIX}")
-endif()
diff --git a/buildcc/lib/env/CMakeLists.txt b/buildcc/lib/env/CMakeLists.txt
index 29d07dba..ecc6080b 100644
--- a/buildcc/lib/env/CMakeLists.txt
+++ b/buildcc/lib/env/CMakeLists.txt
@@ -6,9 +6,13 @@ if (${TESTING})
 
         src/env.cpp
         src/task_state.cpp
+
+        src/command.cpp
+        mock/execute.cpp
     )
     target_include_directories(mock_env PUBLIC 
         ${CMAKE_CURRENT_SOURCE_DIR}/include
+        ${CMAKE_CURRENT_SOURCE_DIR}/mock/include
     )
     target_link_libraries(mock_env PUBLIC
         fmt::fmt-header-only
@@ -28,8 +32,12 @@ if (${TESTING})
     add_executable(test_task_state test/test_task_state.cpp)
     target_link_libraries(test_task_state PRIVATE mock_env)
 
+    add_executable(test_command test/test_command.cpp)
+    target_link_libraries(test_command PRIVATE mock_env)
+
     add_test(NAME test_env_util COMMAND test_env_util)
     add_test(NAME test_task_state COMMAND test_task_state)
+    add_test(NAME test_command COMMAND test_command)
 endif()
 
 set(ENV_SRCS
@@ -48,6 +56,10 @@ set(ENV_SRCS
 
     src/task_state.cpp
     include/env/task_state.h
+
+    src/command.cpp
+    src/execute.cpp
+    include/env/command.h
 )
 
 if(${BUILDCC_BUILD_AS_SINGLE_LIB})
@@ -74,15 +86,14 @@ if(${BUILDCC_BUILD_AS_INTERFACE})
     target_link_options(env PRIVATE ${BUILD_LINK_FLAGS})
     target_link_libraries(env PRIVATE
         spdlog::spdlog_header_only
+        tiny-process-library::tiny-process-library
     )
+endif()
 
-    # Env install
-    if (${BUILDCC_INSTALL})
+if (${BUILDCC_INSTALL})
+    if (${BUILDCC_BUILD_AS_INTERFACE})
         install(TARGETS env DESTINATION lib EXPORT envConfig)
         install(EXPORT envConfig DESTINATION "${BUILDCC_INSTALL_LIB_PREFIX}/env")
     endif()
-endif()
-
-if (${BUILDCC_INSTALL})
     install(DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/include/ DESTINATION "${BUILDCC_INSTALL_HEADER_PREFIX}")
 endif()
diff --git a/buildcc/lib/env/include/env/assert_fatal.h b/buildcc/lib/env/include/env/assert_fatal.h
index d1006d7e..b7754670 100644
--- a/buildcc/lib/env/include/env/assert_fatal.h
+++ b/buildcc/lib/env/include/env/assert_fatal.h
@@ -32,7 +32,8 @@ namespace buildcc::env {
 /**
  * @brief Compile time expr asserts fatally when false
  */
-template <bool expr> inline void assert_fatal(const char *message) {
+template <bool expr>
+inline void assert_fatal([[maybe_unused]] const char *message) {
   if constexpr (!expr) {
     env::log_critical("assert", message);
     assert_handle_fatal();
diff --git a/buildcc/lib/command/include/command/command.h b/buildcc/lib/env/include/env/command.h
similarity index 96%
rename from buildcc/lib/command/include/command/command.h
rename to buildcc/lib/env/include/env/command.h
index 7183ae97..79e763b6 100644
--- a/buildcc/lib/command/include/command/command.h
+++ b/buildcc/lib/env/include/env/command.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef COMMAND_COMMAND_H_
-#define COMMAND_COMMAND_H_
+#ifndef ENV_COMMAND_H_
+#define ENV_COMMAND_H_
 
 #include <filesystem>
 #include <optional>
@@ -25,7 +25,7 @@
 
 namespace fs = std::filesystem;
 
-namespace buildcc {
+namespace buildcc::env {
 
 class Command {
 public:
@@ -82,6 +82,6 @@ class Command {
   std::unordered_map<std::string, std::string> default_values_;
 };
 
-} // namespace buildcc
+} // namespace buildcc::env
 
 #endif
diff --git a/buildcc/lib/command/mock/execute.cpp b/buildcc/lib/env/mock/execute.cpp
similarity index 95%
rename from buildcc/lib/command/mock/execute.cpp
rename to buildcc/lib/env/mock/execute.cpp
index 8ff8555c..642411e4 100644
--- a/buildcc/lib/command/mock/execute.cpp
+++ b/buildcc/lib/env/mock/execute.cpp
@@ -1,10 +1,10 @@
-#include "command/command.h"
+#include "env/command.h"
 
 #include "expect_command.h"
 
 #include "CppUTestExt/MockSupport.h"
 
-namespace buildcc {
+namespace buildcc::env {
 
 static constexpr const char *const EXECUTE_FUNCTION = "execute";
 static constexpr const char *const STDOUT_DATA_STRING = "stdout_data";
@@ -48,4 +48,4 @@ void CommandExpect_Execute(unsigned int calls, bool expectation,
 
 } // namespace m
 
-} // namespace buildcc
+} // namespace buildcc::env
diff --git a/buildcc/lib/command/mock/expect_command.h b/buildcc/lib/env/mock/include/expect_command.h
similarity index 72%
rename from buildcc/lib/command/mock/expect_command.h
rename to buildcc/lib/env/mock/include/expect_command.h
index e6eeed19..7149f594 100644
--- a/buildcc/lib/command/mock/expect_command.h
+++ b/buildcc/lib/env/mock/include/expect_command.h
@@ -1,17 +1,17 @@
-#ifndef COMMAND_MOCK_EXPECT_COMMAND_H_
-#define COMMAND_MOCK_EXPECT_COMMAND_H_
+#ifndef ENV_MOCK_EXPECT_COMMAND_H_
+#define ENV_MOCK_EXPECT_COMMAND_H_
 
 #include <string>
 #include <vector>
 
 constexpr const char *const TEST_VECTOR_STRING_TYPE = "vector_string";
 
-namespace buildcc::m {
+namespace buildcc::env::m {
 
 void CommandExpect_Execute(unsigned int calls, bool expectation,
                            std::vector<std::string> *stdout_data = nullptr,
                            std::vector<std::string> *stderr_data = nullptr);
 
-} // namespace buildcc::m
+} // namespace buildcc::env::m
 
 #endif
diff --git a/buildcc/lib/command/mock/mock_command_copier.h b/buildcc/lib/env/mock/include/mock_command_copier.h
similarity index 78%
rename from buildcc/lib/command/mock/mock_command_copier.h
rename to buildcc/lib/env/mock/include/mock_command_copier.h
index db86b97c..f9e0e70c 100644
--- a/buildcc/lib/command/mock/mock_command_copier.h
+++ b/buildcc/lib/env/mock/include/mock_command_copier.h
@@ -1,12 +1,12 @@
-#ifndef COMMAND_MOCK_MOCK_COMMAND_COPIER_H_
-#define COMMAND_MOCK_MOCK_COMMAND_COPIER_H_
+#ifndef ENV_MOCK_MOCK_COMMAND_COPIER_H_
+#define ENV_MOCK_MOCK_COMMAND_COPIER_H_
 
 #include <string>
 #include <vector>
 
 #include "CppUTestExt/MockSupport.h"
 
-namespace buildcc::m {
+namespace buildcc::env::m {
 
 class VectorStringCopier : public MockNamedValueCopier {
 public:
@@ -23,6 +23,6 @@ class VectorStringCopier : public MockNamedValueCopier {
   }
 };
 
-} // namespace buildcc::m
+} // namespace buildcc::env::m
 
 #endif
diff --git a/buildcc/lib/command/src/command.cpp b/buildcc/lib/env/src/command.cpp
similarity index 96%
rename from buildcc/lib/command/src/command.cpp
rename to buildcc/lib/env/src/command.cpp
index 5a767b51..febb59c8 100644
--- a/buildcc/lib/command/src/command.cpp
+++ b/buildcc/lib/env/src/command.cpp
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "command/command.h"
+#include "env/command.h"
 
 #include <algorithm>
 
@@ -24,7 +24,7 @@
 #include "env/assert_fatal.h"
 #include "env/logging.h"
 
-namespace buildcc {
+namespace buildcc::env {
 
 void Command::AddDefaultArgument(const std::string &key,
                                  const std::string &value) {
@@ -64,4 +64,4 @@ std::string Command::Construct(
   return fmt::vformat(pattern, store);
 }
 
-} // namespace buildcc
+} // namespace buildcc::env
diff --git a/buildcc/lib/command/src/execute.cpp b/buildcc/lib/env/src/execute.cpp
similarity index 96%
rename from buildcc/lib/command/src/execute.cpp
rename to buildcc/lib/env/src/execute.cpp
index a0e80841..3ff6032f 100644
--- a/buildcc/lib/command/src/execute.cpp
+++ b/buildcc/lib/env/src/execute.cpp
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "command/command.h"
+#include "env/command.h"
 
 #include "fmt/format.h"
 
@@ -39,7 +39,7 @@ get_working_directory(const std::optional<fs::path> &working_directory) {
 
 } // namespace
 
-namespace buildcc {
+namespace buildcc::env {
 
 bool Command::Execute(const std::string &command,
                       const std::optional<fs::path> &working_directory,
@@ -64,4 +64,4 @@ bool Command::Execute(const std::string &command,
   return process.get_exit_status() == 0;
 }
 
-} // namespace buildcc
+} // namespace buildcc::env
diff --git a/buildcc/lib/command/test/test_command.cpp b/buildcc/lib/env/test/test_command.cpp
similarity index 87%
rename from buildcc/lib/command/test/test_command.cpp
rename to buildcc/lib/env/test/test_command.cpp
index 74b69edb..e1e1684c 100644
--- a/buildcc/lib/command/test/test_command.cpp
+++ b/buildcc/lib/env/test/test_command.cpp
@@ -1,4 +1,4 @@
-#include "command/command.h"
+#include "env/command.h"
 
 // NOTE, Make sure all these includes are AFTER the system and header includes
 #include "CppUTest/CommandLineTestRunner.h"
@@ -13,18 +13,18 @@ TEST_GROUP(CommandTestGroup)
 // clang-format on
 
 TEST(CommandTestGroup, Construct_InvalidFormat) {
-  buildcc::Command command;
+  buildcc::env::Command command;
   CHECK_THROWS(std::exception, command.Construct("{test}"));
 }
 
 TEST(CommandTestGroup, Construct_Basic) {
-  buildcc::Command command;
+  buildcc::env::Command command;
   std::string s = command.Construct("{}", {{"", "hi"}});
   STRCMP_EQUAL(s.c_str(), "hi");
 }
 
 TEST(CommandTestGroup, Construct_MultipleArgs) {
-  buildcc::Command command;
+  buildcc::env::Command command;
   command.AddDefaultArguments({
       {"h", "hello"},
       {"w", "world"},
@@ -37,12 +37,12 @@ TEST(CommandTestGroup, Construct_MultipleArgs) {
 }
 
 TEST(CommandTestGroup, Construct_BadArguments) {
-  buildcc::Command command;
+  buildcc::env::Command command;
   CHECK_THROWS(std::exception, command.Construct("{}", {{nullptr, "hi"}}));
 }
 
 TEST(CommandTestGroup, GetDefaultValueByKey) {
-  buildcc::Command command;
+  buildcc::env::Command command;
   command.AddDefaultArgument("key", "value");
   const std::string &value = command.GetDefaultValueByKey("key");
 
@@ -50,7 +50,7 @@ TEST(CommandTestGroup, GetDefaultValueByKey) {
 }
 
 TEST(CommandTestGroup, GetDefaultValueByKey_BadKey) {
-  buildcc::Command command;
+  buildcc::env::Command command;
   command.AddDefaultArgument("key", "value");
   CHECK_THROWS(std::exception, command.GetDefaultValueByKey("bad_key"));
 }
diff --git a/buildcc/lib/target/include/target/generator.h b/buildcc/lib/target/include/target/generator.h
index b2d6baec..0436d128 100644
--- a/buildcc/lib/target/include/target/generator.h
+++ b/buildcc/lib/target/include/target/generator.h
@@ -28,7 +28,7 @@
 #include "env/env.h"
 #include "env/task_state.h"
 
-#include "command/command.h"
+#include "env/command.h"
 
 #include "target/interface/builder_interface.h"
 
@@ -138,7 +138,7 @@ class Generator : public BuilderInterface {
   // Internal
   std::mutex task_state_mutex_;
   env::TaskState task_state_{env::TaskState::SUCCESS};
-  Command command_;
+  env::Command command_;
   tf::Taskflow tf_;
 };
 
diff --git a/buildcc/lib/target/include/target/target.h b/buildcc/lib/target/include/target/target.h
index 23b7a541..2dc6c4f5 100644
--- a/buildcc/lib/target/include/target/target.h
+++ b/buildcc/lib/target/include/target/target.h
@@ -52,7 +52,7 @@
 #include "env/task_state.h"
 
 // Components
-#include "command/command.h"
+#include "env/command.h"
 #include "toolchain/toolchain.h"
 
 // Third Party
@@ -161,7 +161,7 @@ class Target : public BuilderInterface,
   internal::path_unordered_set compiled_source_files_;
 
   //
-  Command command_;
+  env::Command command_;
   tf::Taskflow tf_;
 };
 
diff --git a/buildcc/lib/target/src/generator/task.cpp b/buildcc/lib/target/src/generator/task.cpp
index e802fd97..77796998 100644
--- a/buildcc/lib/target/src/generator/task.cpp
+++ b/buildcc/lib/target/src/generator/task.cpp
@@ -16,7 +16,7 @@
 
 #include "target/generator.h"
 
-#include "command/command.h"
+#include "env/command.h"
 
 namespace {
 constexpr const char *const kStartGeneratorTaskName = "Start Generator";
@@ -51,7 +51,7 @@ void Generator::GenerateTask() {
   tf::Task generate_task = tf_.emplace([&](tf::Subflow &subflow) {
     auto run_command = [this](const std::string &command) {
       try {
-        bool success = Command::Execute(command);
+        bool success = env::Command::Execute(command);
         env::assert_throw(success, fmt::format("{} failed", command));
       } catch (...) {
         std::lock_guard<std::mutex> guard(task_state_mutex_);
diff --git a/buildcc/lib/target/src/target/friend/compile_pch.cpp b/buildcc/lib/target/src/target/friend/compile_pch.cpp
index 6ab37919..82f35444 100644
--- a/buildcc/lib/target/src/target/friend/compile_pch.cpp
+++ b/buildcc/lib/target/src/target/friend/compile_pch.cpp
@@ -47,7 +47,7 @@ void AggregateToFile(const fs::path &filename,
     aggregated_includes.append(temp);
   }
 
-  buildcc::Command command;
+  buildcc::env::Command command;
   std::string constructed_output = command.Construct(
       kFormat, {
                    {"aggregated_includes", aggregated_includes},
@@ -108,7 +108,7 @@ void CompilePch::BuildCompile() {
           env::save_file(p.c_str(), {"//Generated by BuildCC"}, false);
       env::assert_throw(save, fmt::format("Could not save {}", p));
     }
-    bool success = Command::Execute(command_);
+    bool success = env::Command::Execute(command_);
     env::assert_throw(success, "Failed to compile pch");
     target_.storer_.pch_compiled = true;
   }
diff --git a/buildcc/lib/target/src/target/friend/link_target.cpp b/buildcc/lib/target/src/target/friend/link_target.cpp
index 3474fb4b..ec935194 100644
--- a/buildcc/lib/target/src/target/friend/link_target.cpp
+++ b/buildcc/lib/target/src/target/friend/link_target.cpp
@@ -90,7 +90,7 @@ void LinkTarget::BuildLink() {
   }
 
   if (target_.dirty_) {
-    bool success = Command::Execute(command_);
+    bool success = env::Command::Execute(command_);
     env::assert_throw(success, "Failed to link target");
     target_.storer_.target_linked = true;
   }
diff --git a/buildcc/lib/target/src/target/target.cpp b/buildcc/lib/target/src/target/target.cpp
index 73a7d5a1..807b1bfb 100644
--- a/buildcc/lib/target/src/target/target.cpp
+++ b/buildcc/lib/target/src/target/target.cpp
@@ -89,9 +89,8 @@ void Target::RecheckExternalLib(
                  std::bind(&Target::ExternalLibChanged, this));
 }
 
-std::optional<std::string>
-Target::SelectCompileFlags(TargetFileExt type) const {
-  switch (type) {
+std::optional<std::string> Target::SelectCompileFlags(TargetFileExt ext) const {
+  switch (ext) {
   case TargetFileExt::Asm:
     return internal::aggregate(GetCurrentAsmCompileFlags());
     break;
@@ -107,8 +106,8 @@ Target::SelectCompileFlags(TargetFileExt type) const {
   return {};
 }
 
-std::optional<std::string> Target::SelectCompiler(TargetFileExt type) const {
-  switch (type) {
+std::optional<std::string> Target::SelectCompiler(TargetFileExt ext) const {
+  switch (ext) {
   case TargetFileExt::Asm:
     return GetToolchain().GetAsmCompiler();
     break;
diff --git a/buildcc/lib/target/src/target/tasks.cpp b/buildcc/lib/target/src/target/tasks.cpp
index 559f0798..bf779e77 100644
--- a/buildcc/lib/target/src/target/tasks.cpp
+++ b/buildcc/lib/target/src/target/tasks.cpp
@@ -117,8 +117,8 @@ void CompileObject::Task() {
         (void)subflow
             .emplace([this, s]() {
               try {
-                bool success =
-                    Command::Execute(GetObjectData(s.GetPathname()).command);
+                bool success = env::Command::Execute(
+                    GetObjectData(s.GetPathname()).command);
                 env::assert_throw(success, "Could not compile source");
 
                 // NOTE, If conmpilation is successful we update the source
diff --git a/buildcc/lib/target/test/target/test_generator.cpp b/buildcc/lib/target/test/target/test_generator.cpp
index db63e41d..b0e927e8 100644
--- a/buildcc/lib/target/test/target/test_generator.cpp
+++ b/buildcc/lib/target/test/target/test_generator.cpp
@@ -40,7 +40,7 @@ TEST(GeneratorTestGroup, Generator_Build) {
   generator.AddCommand("{compiler} -o {gen_build_dir}/dummy_main.exe "
                        "{gen_root_dir}/dummy_main.c");
 
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   generator.Build();
   buildcc::base::m::GeneratorRunner(generator);
 
@@ -60,7 +60,7 @@ TEST(GeneratorTestGroup, Generator_BuildParallel) {
   generator.AddCommand("{compiler} -o {gen_build_dir}/dummy_main.exe "
                        "{gen_root_dir}/dummy_main.c");
 
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   generator.Build();
   buildcc::base::m::GeneratorRunner(generator);
 
@@ -79,7 +79,7 @@ TEST(GeneratorTestGroup, Generator_Identifier) {
   generator.AddOutput("{gen_build_dir}/dummy_main.exe", "dummy_main_exe");
   generator.AddCommand("{compiler} -o {dummy_main_exe} {dummy_main_c}");
 
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   generator.Build();
   buildcc::base::m::GeneratorRunner(generator);
 
@@ -98,7 +98,7 @@ TEST(GeneratorTestGroup, Generator_Rebuild) {
                              {"compiler", "gcc"},
                          });
 
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     generator.Build();
     buildcc::base::m::GeneratorRunner(generator);
   }
@@ -130,7 +130,7 @@ TEST(GeneratorTestGroup, Generator_Rebuild_Inputs) {
     generator.AddCommand("gcc -o {gen_build_dir}/new_source.exe "
                          "{gen_root_dir}/new_source.cpp");
 
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     generator.Build();
     buildcc::base::m::GeneratorRunner(generator);
   }
@@ -143,7 +143,7 @@ TEST(GeneratorTestGroup, Generator_Rebuild_Inputs) {
                          "{gen_root_dir}/new_source.cpp");
 
     buildcc::base::m::GeneratorExpect_InputRemoved(1, &generator);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     generator.Build();
     buildcc::base::m::GeneratorRunner(generator);
   }
@@ -157,7 +157,7 @@ TEST(GeneratorTestGroup, Generator_Rebuild_Inputs) {
                          "{gen_root_dir}/new_source.cpp");
 
     buildcc::base::m::GeneratorExpect_InputAdded(1, &generator);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     generator.Build();
     buildcc::base::m::GeneratorRunner(generator);
   }
@@ -178,7 +178,7 @@ TEST(GeneratorTestGroup, Generator_Rebuild_Inputs) {
     generator.AddCommand("gcc -o {gen_build_dir}/new_source.cpp.exe "
                          "{gen_root_dir}/new_source.cpp");
     buildcc::base::m::GeneratorExpect_InputUpdated(1, &generator);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     generator.Build();
     buildcc::base::m::GeneratorRunner(generator);
   }
@@ -198,7 +198,7 @@ TEST(GeneratorTestGroup, Generator_Rebuild_Outputs) {
                              {"compiler", "gcc"},
                          });
 
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     generator.Build();
     buildcc::base::m::GeneratorRunner(generator);
   }
@@ -213,7 +213,7 @@ TEST(GeneratorTestGroup, Generator_Rebuild_Outputs) {
                          });
 
     buildcc::base::m::GeneratorExpect_OutputChanged(1, &generator);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     generator.Build();
     buildcc::base::m::GeneratorRunner(generator);
   }
@@ -229,7 +229,7 @@ TEST(GeneratorTestGroup, Generator_Rebuild_Outputs) {
                          });
 
     buildcc::base::m::GeneratorExpect_OutputChanged(1, &generator);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     generator.Build();
     buildcc::base::m::GeneratorRunner(generator);
   }
@@ -249,7 +249,7 @@ TEST(GeneratorTestGroup, Generator_Rebuild_Commands) {
                              {"compiler", "gcc"},
                          });
 
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     generator.Build();
     buildcc::base::m::GeneratorRunner(generator);
   }
@@ -264,7 +264,7 @@ TEST(GeneratorTestGroup, Generator_Rebuild_Commands) {
                          });
 
     buildcc::base::m::GeneratorExpect_CommandChanged(1, &generator);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     generator.Build();
     buildcc::base::m::GeneratorRunner(generator);
   }
@@ -277,7 +277,7 @@ TEST(GeneratorTestGroup, Generator_Rebuild_Commands) {
                          "{gen_root_dir}/dummy_main.c");
 
     buildcc::base::m::GeneratorExpect_CommandChanged(1, &generator);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     generator.Build();
     buildcc::base::m::GeneratorRunner(generator);
   }
@@ -356,7 +356,7 @@ TEST(GeneratorTestGroup, Generator_FailedGenerateCommand) {
   generator.AddCommand("{compiler} -o {gen_build_dir}/dummy_main.exe "
                        "{gen_root_dir}/dummy_main.c");
 
-  buildcc::m::CommandExpect_Execute(1, false);
+  buildcc::env::m::CommandExpect_Execute(1, false);
   generator.Build();
   buildcc::base::m::GeneratorRunner(generator);
 
@@ -381,7 +381,7 @@ TEST(GeneratorTestGroup, Generator_FailedStore) {
   generator.AddCommand("{compiler} -o {gen_build_dir}/dummy_main.exe "
                        "{gen_root_dir}/dummy_main.c");
 
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   generator.Build();
   buildcc::base::m::GeneratorRunner(generator);
 
@@ -429,7 +429,7 @@ TEST(GeneratorTestGroup, FailedEnvTaskState_Rebuild) {
                          "{gen_root_dir}/dummy_main.c");
 
     generator.Build();
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     buildcc::base::m::GeneratorRunner(generator);
   }
 
@@ -451,7 +451,7 @@ TEST(GeneratorTestGroup, FailedGenerateCommand_Rebuild) {
     generator.AddCommand("{compiler} -o {gen_build_dir}/dummy_main.exe "
                          "{gen_root_dir}/dummy_main.c");
 
-    buildcc::m::CommandExpect_Execute(1, false);
+    buildcc::env::m::CommandExpect_Execute(1, false);
     generator.Build();
     buildcc::base::m::GeneratorRunner(generator);
   }
@@ -472,7 +472,7 @@ TEST(GeneratorTestGroup, FailedGenerateCommand_Rebuild) {
     generator.AddCommand("{compiler} -o {gen_build_dir}/dummy_main.exe "
                          "{gen_root_dir}/dummy_main.c");
 
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     generator.Build();
     buildcc::base::m::GeneratorRunner(generator);
   }
diff --git a/buildcc/lib/target/test/target/test_target_external_lib.cpp b/buildcc/lib/target/test/target/test_target_external_lib.cpp
index a8d32691..d98010fe 100644
--- a/buildcc/lib/target/test/target/test_target_external_lib.cpp
+++ b/buildcc/lib/target/test/target/test_target_external_lib.cpp
@@ -45,8 +45,8 @@ TEST(TargetTestExternalLib, TestAddLibDir) {
   exe.AddSource("foo_main.cpp");
   exe.AddLibDir(exe.GetTargetPath().parent_path());
 
-  buildcc::m::CommandExpect_Execute(1, true);
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   exe.Build();
   buildcc::base::m::TargetRunner(exe);
   CHECK_TRUE(exe.IsBuilt());
@@ -73,8 +73,8 @@ TEST(TargetTestExternalLib, TestAddExternalLibDep_Simple) {
   exe.AddLibDir(exe.GetTargetPath().parent_path());
   exe.AddLibDep("-lfoo");
 
-  buildcc::m::CommandExpect_Execute(1, true);
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   exe.Build();
   buildcc::base::m::TargetRunner(exe);
   CHECK_TRUE(exe.IsBuilt());
@@ -102,8 +102,8 @@ TEST(TargetTestExternalLib, TestAddExternalLibDep_RebuildChanged) {
     exe.AddSource("foo_main.cpp");
     exe.AddLibDir(exe.GetTargetPath().parent_path());
 
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     exe.Build();
     buildcc::base::m::TargetRunner(exe);
     CHECK_TRUE(exe.IsBuilt());
@@ -118,7 +118,7 @@ TEST(TargetTestExternalLib, TestAddExternalLibDep_RebuildChanged) {
     exe.AddLibDep("-lfoo");
 
     buildcc::base::m::TargetExpect_ExternalLibChanged(1, &exe);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     exe.Build();
     buildcc::base::m::TargetRunner(exe);
     CHECK_TRUE(exe.IsBuilt());
@@ -132,7 +132,7 @@ TEST(TargetTestExternalLib, TestAddExternalLibDep_RebuildChanged) {
     exe.AddLibDir(exe.GetTargetPath().parent_path());
 
     buildcc::base::m::TargetExpect_ExternalLibChanged(1, &exe);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     exe.Build();
     buildcc::base::m::TargetRunner(exe);
     CHECK_TRUE(exe.IsBuilt());
diff --git a/buildcc/lib/target/test/target/test_target_failure_states.cpp b/buildcc/lib/target/test/target/test_target_failure_states.cpp
index 36d4c31e..42f06eb6 100644
--- a/buildcc/lib/target/test/target/test_target_failure_states.cpp
+++ b/buildcc/lib/target/test/target/test_target_failure_states.cpp
@@ -51,7 +51,7 @@ TEST(TargetTestFailureStates, CompilePchFailure) {
   target.AddPch("include/include_header.h");
   target.Build();
 
-  buildcc::m::CommandExpect_Execute(1, false); // PCH compile
+  buildcc::env::m::CommandExpect_Execute(1, false); // PCH compile
   buildcc::base::m::TargetRunner(target);
 
   CHECK(target.GetTaskState() == buildcc::env::TaskState::FAILURE);
@@ -67,8 +67,8 @@ TEST(TargetTestFailureStates, CompileObjectFailure) {
   target.AddSource("dummy_main.c");
   target.Build();
 
-  buildcc::m::CommandExpect_Execute(1, false); // compile
-  buildcc::m::CommandExpect_Execute(1, true);  // compile
+  buildcc::env::m::CommandExpect_Execute(1, false); // compile
+  buildcc::env::m::CommandExpect_Execute(1, true);  // compile
   buildcc::base::m::TargetRunner(target);
 
   CHECK(target.GetTaskState() == buildcc::env::TaskState::FAILURE);
@@ -96,8 +96,8 @@ TEST(TargetTestFailureStates, LinkTargetFailure) {
   target.AddSource("dummy_main.cpp");
   target.Build();
 
-  buildcc::m::CommandExpect_Execute(1, true);  // compile
-  buildcc::m::CommandExpect_Execute(1, false); // link
+  buildcc::env::m::CommandExpect_Execute(1, true);  // compile
+  buildcc::env::m::CommandExpect_Execute(1, false); // link
   buildcc::base::m::TargetRunner(target);
 
   CHECK(target.GetTaskState() == buildcc::env::TaskState::FAILURE);
@@ -114,8 +114,8 @@ TEST(TargetTestFailureStates, EndTaskStoreFailure) {
   fs::remove_all(
       target.GetTargetBuildDir()); // removing this path causes store failure
 
-  buildcc::m::CommandExpect_Execute(1, true); // compile
-  buildcc::m::CommandExpect_Execute(1, true); // link
+  buildcc::env::m::CommandExpect_Execute(1, true); // compile
+  buildcc::env::m::CommandExpect_Execute(1, true); // link
   buildcc::base::m::TargetRunner(target);
 
   CHECK(target.GetTaskState() == buildcc::env::TaskState::FAILURE);
@@ -152,8 +152,8 @@ TEST(TargetTestFailureStates, StartTaskEnvFailure_Rebuild) {
     target.AddSource("dummy_main.cpp");
     target.Build();
 
-    buildcc::m::CommandExpect_Execute(1, true); // compile
-    buildcc::m::CommandExpect_Execute(1, true); // link
+    buildcc::env::m::CommandExpect_Execute(1, true); // compile
+    buildcc::env::m::CommandExpect_Execute(1, true); // link
     buildcc::base::m::TargetRunner(target);
 
     CHECK(target.GetTaskState() == buildcc::env::TaskState::SUCCESS);
@@ -173,7 +173,7 @@ TEST(TargetTestFailureStates, CompilePchFailure_Rebuild) {
     target.AddPch("include/include_header.h");
     target.Build();
 
-    buildcc::m::CommandExpect_Execute(1, false); // PCH compile
+    buildcc::env::m::CommandExpect_Execute(1, false); // PCH compile
     buildcc::base::m::TargetRunner(target);
 
     CHECK(target.GetTaskState() == buildcc::env::TaskState::FAILURE);
@@ -193,9 +193,9 @@ TEST(TargetTestFailureStates, CompilePchFailure_Rebuild) {
     target.AddPch("include/include_header.h");
     target.Build();
 
-    buildcc::m::CommandExpect_Execute(1, true); // PCH compile
-    buildcc::m::CommandExpect_Execute(1, true); // Object compile
-    buildcc::m::CommandExpect_Execute(1, true); // Link target
+    buildcc::env::m::CommandExpect_Execute(1, true); // PCH compile
+    buildcc::env::m::CommandExpect_Execute(1, true); // Object compile
+    buildcc::env::m::CommandExpect_Execute(1, true); // Link target
 
     buildcc::base::m::TargetRunner(target);
 
@@ -216,8 +216,8 @@ TEST(TargetTestFailureStates, CompileObjectFailure_Rebuild) {
     target.AddSource("dummy_main.c");
     target.Build();
 
-    buildcc::m::CommandExpect_Execute(1, false); // compile
-    buildcc::m::CommandExpect_Execute(1, true);  // compile
+    buildcc::env::m::CommandExpect_Execute(1, false); // compile
+    buildcc::env::m::CommandExpect_Execute(1, true);  // compile
     buildcc::base::m::TargetRunner(target);
 
     CHECK(target.GetTaskState() == buildcc::env::TaskState::FAILURE);
@@ -246,9 +246,9 @@ TEST(TargetTestFailureStates, CompileObjectFailure_Rebuild) {
 
     // NOTE, The other one does not compile since it already compiled
     // successfully earlier!
-    buildcc::m::CommandExpect_Execute(1, true); // compile
+    buildcc::env::m::CommandExpect_Execute(1, true); // compile
     buildcc::base::m::TargetExpect_SourceAdded(1, &target);
-    buildcc::m::CommandExpect_Execute(1, true); // link
+    buildcc::env::m::CommandExpect_Execute(1, true); // link
     buildcc::base::m::TargetRunner(target);
 
     CHECK(target.GetTaskState() == buildcc::env::TaskState::SUCCESS);
@@ -266,8 +266,8 @@ TEST(TargetTestFailureStates, LinkTargetFailure_Rebuild) {
     target.AddSource("dummy_main.cpp");
     target.Build();
 
-    buildcc::m::CommandExpect_Execute(1, true);  // compile
-    buildcc::m::CommandExpect_Execute(1, false); // link
+    buildcc::env::m::CommandExpect_Execute(1, true);  // compile
+    buildcc::env::m::CommandExpect_Execute(1, false); // link
     buildcc::base::m::TargetRunner(target);
 
     CHECK(target.GetTaskState() == buildcc::env::TaskState::FAILURE);
@@ -285,7 +285,7 @@ TEST(TargetTestFailureStates, LinkTargetFailure_Rebuild) {
     target.Build();
 
     // we do not recompile
-    buildcc::m::CommandExpect_Execute(1, true); // link
+    buildcc::env::m::CommandExpect_Execute(1, true); // link
     buildcc::base::m::TargetRunner(target);
 
     CHECK(target.GetTaskState() == buildcc::env::TaskState::SUCCESS);
diff --git a/buildcc/lib/target/test/target/test_target_flags.cpp b/buildcc/lib/target/test/target/test_target_flags.cpp
index daafebcd..7120f3dc 100644
--- a/buildcc/lib/target/test/target/test_target_flags.cpp
+++ b/buildcc/lib/target/test/target/test_target_flags.cpp
@@ -54,8 +54,8 @@ TEST(TargetTestPreprocessorFlagGroup, Target_AddPreprocessorFlag) {
   simple.AddSource(DUMMY_MAIN);
   simple.AddPreprocessorFlag("-DCOMPILE=1");
 
-  buildcc::m::CommandExpect_Execute(1, true);
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   simple.Build();
   buildcc::base::m::TargetRunner(simple);
   CHECK_TRUE(simple.IsBuilt());
@@ -86,8 +86,8 @@ TEST(TargetTestPreprocessorFlagGroup, Target_ChangedPreprocessorFlag) {
     simple.AddSource(DUMMY_MAIN);
     simple.AddPreprocessorFlag("-DCOMPILE=1");
 
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
     CHECK_TRUE(simple.IsBuilt());
@@ -98,8 +98,8 @@ TEST(TargetTestPreprocessorFlagGroup, Target_ChangedPreprocessorFlag) {
                                  gcc, "data");
     simple.AddSource(DUMMY_MAIN);
     buildcc::base::m::TargetExpect_FlagChanged(1, &simple);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
     CHECK_TRUE(simple.IsBuilt());
@@ -112,8 +112,8 @@ TEST(TargetTestPreprocessorFlagGroup, Target_ChangedPreprocessorFlag) {
     simple.AddSource(DUMMY_MAIN);
     simple.AddPreprocessorFlag("-DRANDOM=1");
     buildcc::base::m::TargetExpect_FlagChanged(1, &simple);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
     CHECK_TRUE(simple.IsBuilt());
@@ -152,8 +152,8 @@ TEST(TargetTestCommonCompileFlagsGroup, Target_AddCommonCompileFlag) {
   simple.AddCommonCompileFlag("-O0");
   simple.AddCommonCompileFlag("-g");
 
-  buildcc::m::CommandExpect_Execute(1, true);
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   simple.Build();
   buildcc::base::m::TargetRunner(simple);
   CHECK_TRUE(simple.IsBuilt());
@@ -185,8 +185,8 @@ TEST(TargetTestCommonCompileFlagsGroup, Target_ChangedCommonCompileFlag) {
     simple.AddCommonCompileFlag("-O0");
     simple.AddCommonCompileFlag("-g");
 
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
     CHECK_TRUE(simple.IsBuilt());
@@ -210,8 +210,8 @@ TEST(TargetTestCommonCompileFlagsGroup, Target_ChangedCommonCompileFlag) {
     simple.AddCommonCompileFlag("-O0");
 
     buildcc::base::m::TargetExpect_FlagChanged(1, &simple);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
     CHECK_TRUE(simple.IsBuilt());
@@ -226,8 +226,8 @@ TEST(TargetTestCommonCompileFlagsGroup, Target_ChangedCommonCompileFlag) {
     simple.AddCommonCompileFlag("-g");
 
     buildcc::base::m::TargetExpect_FlagChanged(1, &simple);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
     CHECK_TRUE(simple.IsBuilt());
@@ -266,8 +266,8 @@ TEST(TargetTestAsmCompileFlagGroup, Target_AddCompileFlag) {
   simple.AddAsmCompileFlag("-O0");
   simple.AddAsmCompileFlag("-g");
 
-  buildcc::m::CommandExpect_Execute(1, true);
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   simple.Build();
   buildcc::base::m::TargetRunner(simple);
   CHECK_TRUE(simple.IsBuilt());
@@ -299,8 +299,8 @@ TEST(TargetTestAsmCompileFlagGroup, Target_ChangedCompileFlag) {
     simple.AddAsmCompileFlag("-O0");
     simple.AddAsmCompileFlag("-g");
 
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
     CHECK_TRUE(simple.IsBuilt());
@@ -325,8 +325,8 @@ TEST(TargetTestAsmCompileFlagGroup, Target_ChangedCompileFlag) {
     simple.AddAsmCompileFlag("-O0");
 
     buildcc::base::m::TargetExpect_FlagChanged(1, &simple);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
     CHECK_TRUE(simple.IsBuilt());
@@ -341,8 +341,8 @@ TEST(TargetTestAsmCompileFlagGroup, Target_ChangedCompileFlag) {
     simple.AddAsmCompileFlag("-g");
 
     buildcc::base::m::TargetExpect_FlagChanged(1, &simple);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
     CHECK_TRUE(simple.IsBuilt());
@@ -380,8 +380,8 @@ TEST(TargetTestCCompileFlagsGroup, Target_AddCompileFlag) {
   simple.AddSource(DUMMY_MAIN);
   simple.AddCCompileFlag("-std=c11");
 
-  buildcc::m::CommandExpect_Execute(1, true);
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   simple.Build();
   buildcc::base::m::TargetRunner(simple);
   CHECK_TRUE(simple.IsBuilt());
@@ -412,8 +412,8 @@ TEST(TargetTestCCompileFlagsGroup, Target_ChangedCompileFlag) {
     simple.AddSource(DUMMY_MAIN);
     simple.AddCCompileFlag("-std=c11");
 
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
     CHECK_TRUE(simple.IsBuilt());
@@ -424,8 +424,8 @@ TEST(TargetTestCCompileFlagsGroup, Target_ChangedCompileFlag) {
                                  gcc, "data");
     simple.AddSource(DUMMY_MAIN);
     buildcc::base::m::TargetExpect_FlagChanged(1, &simple);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
     CHECK_TRUE(simple.IsBuilt());
@@ -438,8 +438,8 @@ TEST(TargetTestCCompileFlagsGroup, Target_ChangedCompileFlag) {
     simple.AddSource(DUMMY_MAIN);
     simple.AddCCompileFlag("-std=c11");
     buildcc::base::m::TargetExpect_FlagChanged(1, &simple);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
     CHECK_TRUE(simple.IsBuilt());
@@ -477,8 +477,8 @@ TEST(TargetTestCppCompileFlagsGroup, Target_AddCompileFlag) {
   simple.AddSource(DUMMY_MAIN);
   simple.AddCppCompileFlag("-std=c++17");
 
-  buildcc::m::CommandExpect_Execute(1, true);
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   simple.Build();
   buildcc::base::m::TargetRunner(simple);
   CHECK_TRUE(simple.IsBuilt());
@@ -509,8 +509,8 @@ TEST(TargetTestCppCompileFlagsGroup, Target_ChangedCompileFlag) {
     simple.AddSource(DUMMY_MAIN);
     simple.AddCCompileFlag("-std=c++17");
 
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
     CHECK_TRUE(simple.IsBuilt());
@@ -521,8 +521,8 @@ TEST(TargetTestCppCompileFlagsGroup, Target_ChangedCompileFlag) {
                                  gcc, "data");
     simple.AddSource(DUMMY_MAIN);
     buildcc::base::m::TargetExpect_FlagChanged(1, &simple);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
     CHECK_TRUE(simple.IsBuilt());
@@ -535,8 +535,8 @@ TEST(TargetTestCppCompileFlagsGroup, Target_ChangedCompileFlag) {
     simple.AddSource(DUMMY_MAIN);
     simple.AddCCompileFlag("-std=c++17");
     buildcc::base::m::TargetExpect_FlagChanged(1, &simple);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
     CHECK_TRUE(simple.IsBuilt());
@@ -574,8 +574,8 @@ TEST(TargetTestLinkFlagsGroup, Target_AddLinkFlag) {
   simple.AddSource(DUMMY_MAIN);
   simple.AddLinkFlag("-lm");
 
-  buildcc::m::CommandExpect_Execute(1, true);
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   simple.Build();
   buildcc::base::m::TargetRunner(simple);
   CHECK_TRUE(simple.IsBuilt());
@@ -606,8 +606,8 @@ TEST(TargetTestLinkFlagsGroup, Target_ChangedLinkFlag) {
     simple.AddSource(DUMMY_MAIN);
     simple.AddLinkFlag("-lm");
 
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
     CHECK_TRUE(simple.IsBuilt());
@@ -618,7 +618,7 @@ TEST(TargetTestLinkFlagsGroup, Target_ChangedLinkFlag) {
                                  gcc, "data");
     simple.AddSource(DUMMY_MAIN);
     buildcc::base::m::TargetExpect_FlagChanged(1, &simple);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
     CHECK_TRUE(simple.IsBuilt());
@@ -631,7 +631,7 @@ TEST(TargetTestLinkFlagsGroup, Target_ChangedLinkFlag) {
     simple.AddSource(DUMMY_MAIN);
     simple.AddLinkFlag("-lm");
     buildcc::base::m::TargetExpect_FlagChanged(1, &simple);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
     CHECK_TRUE(simple.IsBuilt());
diff --git a/buildcc/lib/target/test/target/test_target_include_dir.cpp b/buildcc/lib/target/test/target/test_target_include_dir.cpp
index 454f0ad6..19086cd4 100644
--- a/buildcc/lib/target/test/target/test_target_include_dir.cpp
+++ b/buildcc/lib/target/test/target/test_target_include_dir.cpp
@@ -110,8 +110,8 @@ TEST(TargetTestIncludeDirGroup, TargetBuildIncludeDir) {
     // Duplicate include directory
     include_compile.AddIncludeDir(RELATIVE_INCLUDE_DIR);
 
-    buildcc::m::CommandExpect_Execute(2, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(2, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     include_compile.Build();
     buildcc::base::m::TargetRunner(include_compile);
 
@@ -142,8 +142,8 @@ TEST(TargetTestIncludeDirGroup, TargetBuildIncludeDir) {
     include_compile.AddIncludeDir("");
 
     buildcc::base::m::TargetExpect_DirChanged(1, &include_compile);
-    buildcc::m::CommandExpect_Execute(2, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(2, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     include_compile.Build();
     buildcc::base::m::TargetRunner(include_compile);
 
@@ -171,8 +171,8 @@ TEST(TargetTestIncludeDirGroup, TargetBuildIncludeDir) {
     include_compile.AddIncludeDir(RELATIVE_INCLUDE_DIR);
 
     buildcc::base::m::TargetExpect_DirChanged(1, &include_compile);
-    buildcc::m::CommandExpect_Execute(2, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(2, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     include_compile.Build();
     buildcc::base::m::TargetRunner(include_compile);
 
@@ -224,8 +224,8 @@ TEST(TargetTestIncludeDirGroup, TargetBuildHeaderFile) {
     add_header.AddSource(INCLUDE_HEADER_SOURCE);
     add_header.AddIncludeDir(RELATIVE_INCLUDE_DIR);
 
-    buildcc::m::CommandExpect_Execute(2, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(2, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     add_header.Build();
     buildcc::base::m::TargetRunner(add_header);
 
@@ -247,8 +247,8 @@ TEST(TargetTestIncludeDirGroup, TargetBuildHeaderFile) {
     add_header.AddIncludeDir(RELATIVE_INCLUDE_DIR);
 
     buildcc::base::m::TargetExpect_PathAdded(1, &add_header);
-    buildcc::m::CommandExpect_Execute(2, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(2, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     add_header.Build();
     buildcc::base::m::TargetRunner(add_header);
 
@@ -276,8 +276,8 @@ TEST(TargetTestIncludeDirGroup, TargetBuildHeaderFile) {
     add_header.AddIncludeDir(RELATIVE_INCLUDE_DIR);
 
     buildcc::base::m::TargetExpect_PathUpdated(1, &add_header);
-    buildcc::m::CommandExpect_Execute(2, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(2, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     add_header.Build();
     buildcc::base::m::TargetRunner(add_header);
 
@@ -298,8 +298,8 @@ TEST(TargetTestIncludeDirGroup, TargetBuildHeaderFile) {
     add_header.AddIncludeDir(RELATIVE_INCLUDE_DIR);
 
     buildcc::base::m::TargetExpect_PathRemoved(1, &add_header);
-    buildcc::m::CommandExpect_Execute(2, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(2, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     add_header.Build();
     buildcc::base::m::TargetRunner(add_header);
 
diff --git a/buildcc/lib/target/test/target/test_target_lib_dep.cpp b/buildcc/lib/target/test/target/test_target_lib_dep.cpp
index 54363c76..593e56e0 100644
--- a/buildcc/lib/target/test/target/test_target_lib_dep.cpp
+++ b/buildcc/lib/target/test/target/test_target_lib_dep.cpp
@@ -47,8 +47,8 @@ TEST(TargetTestLibDep, StaticLibrary_SimpleBuildTest) {
   foolib.AddSource("foo.cpp", "foo");
   foolib.AddIncludeDir("foo");
 
-  buildcc::m::CommandExpect_Execute(1, true);
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   foolib.Build();
   buildcc::base::m::TargetRunner(foolib);
 
@@ -77,8 +77,8 @@ TEST(TargetTestLibDep, TargetDep_RebuildTest) {
     foolib.AddSource("foo/foo.cpp");
     foolib.AddIncludeDir("foo");
 
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     foolib.Build();
     buildcc::base::m::TargetRunner(foolib);
     buildcc::env::save_file(foolib.GetTargetPath().string().c_str(),
@@ -91,8 +91,8 @@ TEST(TargetTestLibDep, TargetDep_RebuildTest) {
     exe_target.AddIncludeDir("foo");
     exe_target.AddLibDep(foolib);
 
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     exe_target.Build();
     buildcc::base::m::TargetRunner(exe_target);
   }
@@ -132,8 +132,8 @@ TEST(TargetTestLibDep, TargetDep_AddRemoveTest) {
   foolib.AddSource("foo/foo.cpp");
   foolib.AddIncludeDir("foo");
 
-  buildcc::m::CommandExpect_Execute(1, true);
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   foolib.Build();
   buildcc::base::m::TargetRunner(foolib);
 
@@ -148,8 +148,8 @@ TEST(TargetTestLibDep, TargetDep_AddRemoveTest) {
     exe_target.AddSource("empty_main.cpp");
     exe_target.AddIncludeDir("foo");
 
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     exe_target.Build();
     buildcc::base::m::TargetRunner(exe_target);
   }
@@ -164,7 +164,7 @@ TEST(TargetTestLibDep, TargetDep_AddRemoveTest) {
     exe_target.AddLibDep(foolib);
 
     buildcc::base::m::TargetExpect_PathAdded(1, &exe_target);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     exe_target.Build();
     buildcc::base::m::TargetRunner(exe_target);
   }
@@ -177,7 +177,7 @@ TEST(TargetTestLibDep, TargetDep_AddRemoveTest) {
     exe_target.AddIncludeDir("foo");
 
     buildcc::base::m::TargetExpect_PathRemoved(1, &exe_target);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     exe_target.Build();
     buildcc::base::m::TargetRunner(exe_target);
   }
@@ -199,8 +199,8 @@ TEST(TargetTestLibDep, TargetDep_UpdateExistingLibraryTest) {
     foolib.AddSource("foo/foo.cpp");
     foolib.AddIncludeDir("foo");
 
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     foolib.Build();
     buildcc::base::m::TargetRunner(foolib);
 
@@ -214,8 +214,8 @@ TEST(TargetTestLibDep, TargetDep_UpdateExistingLibraryTest) {
     exe_target.AddIncludeDir("foo");
     exe_target.AddLibDep(foolib);
 
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     exe_target.Build();
     buildcc::base::m::TargetRunner(exe_target);
   }
@@ -229,8 +229,8 @@ TEST(TargetTestLibDep, TargetDep_UpdateExistingLibraryTest) {
     foolib.AddIncludeDir("");
 
     buildcc::base::m::TargetExpect_DirChanged(1, &foolib);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     foolib.Build();
     buildcc::base::m::TargetRunner(foolib);
 
@@ -247,7 +247,7 @@ TEST(TargetTestLibDep, TargetDep_UpdateExistingLibraryTest) {
     exe_target.AddLibDep(foolib);
 
     buildcc::base::m::TargetExpect_PathUpdated(1, &exe_target);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     exe_target.Build();
     buildcc::base::m::TargetRunner(exe_target);
   }
diff --git a/buildcc/lib/target/test/target/test_target_lock.cpp b/buildcc/lib/target/test/target/test_target_lock.cpp
index 2e7512a5..7e24fae3 100644
--- a/buildcc/lib/target/test/target/test_target_lock.cpp
+++ b/buildcc/lib/target/test/target/test_target_lock.cpp
@@ -36,7 +36,7 @@ TEST(TargetTestLock, LockState) {
 
   CHECK_FALSE(exe.IsLocked());
 
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   exe.Build();
   buildcc::base::m::TargetRunner(exe);
 
@@ -50,7 +50,7 @@ TEST(TargetTestLock, Lock_Build) {
   buildcc::base::Target exe(NAME, buildcc::base::TargetType::Executable, gcc,
                             "data");
 
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   exe.Build();
   buildcc::base::m::TargetRunner(exe);
 
@@ -64,7 +64,7 @@ TEST(TargetTestLock, Lock_APIs) {
   buildcc::base::Target exe(NAME, buildcc::base::TargetType::Executable, gcc,
                             "data");
 
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   exe.Build();
   buildcc::base::m::TargetRunner(exe);
 
@@ -108,8 +108,8 @@ TEST(TargetTestLock, Unlock_APIs) {
   CHECK_THROWS(std::exception, exe.GetTaskflow());
 
   exe.AddSource("dummy_main.c");
-  buildcc::m::CommandExpect_Execute(1, true);
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   exe.Build();
   buildcc::base::m::TargetRunner(exe);
   mock().checkExpectations();
diff --git a/buildcc/lib/target/test/target/test_target_pch.cpp b/buildcc/lib/target/test/target/test_target_pch.cpp
index e8cc7c3b..fca98eeb 100644
--- a/buildcc/lib/target/test/target/test_target_pch.cpp
+++ b/buildcc/lib/target/test/target/test_target_pch.cpp
@@ -50,8 +50,8 @@ TEST(TargetPchTestGroup, Target_AddPch_Build) {
   target.AddPch("pch/pch_header_1.h");
   target.AddPch("pch/pch_header_2.h");
 
-  buildcc::m::CommandExpect_Execute(1, true);
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   target.Build();
   buildcc::base::m::TargetRunner(target);
   bool exists = fs::exists(target.GetPchHeaderPath());
@@ -75,8 +75,8 @@ TEST(TargetPchTestGroup, Target_AddPch_Rebuild) {
     target.AddPch("pch/pch_header_1.h");
     target.AddPch("pch/pch_header_2.h");
 
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     target.Build();
     buildcc::base::m::TargetRunner(target);
     bool exists = fs::exists(target.GetPchHeaderPath());
@@ -103,8 +103,8 @@ TEST(TargetPchTestGroup, Target_AddPch_Rebuild) {
     target.AddPch("pch/pch_header_1.h");
 
     buildcc::base::m::TargetExpect_PathRemoved(1, &target);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     target.Build();
     buildcc::base::m::TargetRunner(target);
     bool exists = fs::exists(target.GetPchHeaderPath());
@@ -119,8 +119,8 @@ TEST(TargetPchTestGroup, Target_AddPch_Rebuild) {
     target.AddPch("pch/pch_header_2.h");
 
     buildcc::base::m::TargetExpect_PathAdded(1, &target);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     target.Build();
     buildcc::base::m::TargetRunner(target);
     bool exists = fs::exists(target.GetPchHeaderPath());
@@ -141,8 +141,8 @@ TEST(TargetPchTestGroup, Target_AddPch_Rebuild) {
     target.AddPch("pch/pch_header_2.h");
 
     buildcc::base::m::TargetExpect_PathUpdated(1, &target);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     target.Build();
     buildcc::base::m::TargetRunner(target);
     bool exists = fs::exists(target.GetPchHeaderPath());
@@ -162,9 +162,9 @@ TEST(TargetPchTestGroup, Target_AddPch_CppRebuild) {
     target.AddPch("pch/pch_header_2.h");
     target.AddSource("dummy_main.cpp");
 
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     target.Build();
     buildcc::base::m::TargetRunner(target);
     bool exists = fs::exists(target.GetPchHeaderPath());
@@ -193,9 +193,9 @@ TEST(TargetPchTestGroup, Target_AddPch_CppRebuild) {
     target.AddSource("dummy_main.cpp");
 
     buildcc::base::m::TargetExpect_PathRemoved(1, &target);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     target.Build();
     buildcc::base::m::TargetRunner(target);
     bool exists = fs::exists(target.GetPchHeaderPath());
@@ -211,9 +211,9 @@ TEST(TargetPchTestGroup, Target_AddPch_CppRebuild) {
     target.AddSource("dummy_main.cpp");
 
     buildcc::base::m::TargetExpect_PathAdded(1, &target);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     target.Build();
     buildcc::base::m::TargetRunner(target);
     bool exists = fs::exists(target.GetPchHeaderPath());
@@ -235,9 +235,9 @@ TEST(TargetPchTestGroup, Target_AddPch_CppRebuild) {
     target.AddSource("dummy_main.cpp");
 
     buildcc::base::m::TargetExpect_PathUpdated(1, &target);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     target.Build();
     buildcc::base::m::TargetRunner(target);
     bool exists = fs::exists(target.GetPchHeaderPath());
@@ -256,8 +256,8 @@ TEST(TargetPchTestGroup, Target_AddPchCompileFlag_Build) {
   target.AddPch("pch/pch_header_1.h");
   target.AddPch("pch/pch_header_2.h");
 
-  buildcc::m::CommandExpect_Execute(1, true);
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   target.Build();
   buildcc::base::m::TargetRunner(target);
   bool exists = fs::exists(target.GetPchHeaderPath());
@@ -276,8 +276,8 @@ TEST(TargetPchTestGroup, Target_AddPchObjectFlag_Build) {
   target.AddPch("pch/pch_header_1.h");
   target.AddPch("pch/pch_header_2.h");
 
-  buildcc::m::CommandExpect_Execute(1, true);
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   target.Build();
   buildcc::base::m::TargetRunner(target);
   bool exists = fs::exists(target.GetPchHeaderPath());
diff --git a/buildcc/lib/target/test/target/test_target_source.cpp b/buildcc/lib/target/test/target/test_target_source.cpp
index 9553e0f2..05cae41a 100644
--- a/buildcc/lib/target/test/target/test_target_source.cpp
+++ b/buildcc/lib/target/test/target/test_target_source.cpp
@@ -100,8 +100,8 @@ TEST(TargetTestSourceGroup, Target_Build_SourceCompile) {
   simple.AddSource(DUMMY_MAIN);
   simple.Build();
 
-  buildcc::m::CommandExpect_Execute(1, true); // compile
-  buildcc::m::CommandExpect_Execute(1, true); // link
+  buildcc::env::m::CommandExpect_Execute(1, true); // compile
+  buildcc::env::m::CommandExpect_Execute(1, true); // link
   buildcc::base::m::TargetRunner(simple);
 
   CHECK(simple.GetTaskState() == buildcc::env::TaskState::SUCCESS);
@@ -145,9 +145,9 @@ TEST(TargetTestSourceGroup, Target_Build_SourceRecompile) {
     simple.AddSource(DUMMY_MAIN_C);
     simple.AddSource(NEW_SOURCE);
 
-    buildcc::m::CommandExpect_Execute(1, true); // compile
-    buildcc::m::CommandExpect_Execute(1, true); // compile
-    buildcc::m::CommandExpect_Execute(1, true); // link
+    buildcc::env::m::CommandExpect_Execute(1, true); // compile
+    buildcc::env::m::CommandExpect_Execute(1, true); // compile
+    buildcc::env::m::CommandExpect_Execute(1, true); // link
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
 
@@ -172,11 +172,11 @@ TEST(TargetTestSourceGroup, Target_Build_SourceRecompile) {
     buildcc::base::m::TargetExpect_SourceRemoved(1, &simple);
 
     // Added and compiled
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     buildcc::base::m::TargetExpect_SourceAdded(1, &simple);
 
     // Rebuild target
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
 
     // Run the second Build to test Recompile
     simple.Build();
@@ -205,10 +205,10 @@ TEST(TargetTestSourceGroup, Target_Build_SourceRecompile) {
     simple.AddSource(NEW_SOURCE);
     // Run the second Build to test Recompile
 
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     buildcc::base::m::TargetExpect_SourceUpdated(1, &simple);
 
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
 
diff --git a/buildcc/lib/target/test/target/test_target_source_out_of_root.cpp b/buildcc/lib/target/test/target/test_target_source_out_of_root.cpp
index 6dc2f2e9..e37cefb2 100644
--- a/buildcc/lib/target/test/target/test_target_source_out_of_root.cpp
+++ b/buildcc/lib/target/test/target/test_target_source_out_of_root.cpp
@@ -42,8 +42,8 @@ TEST(TargetTestSourceOutOfRootGroup, Add_OutOfRootSource) {
                                gcc, "");
   simple.AddSource("../dummy_main.cpp");
 
-  buildcc::m::CommandExpect_Execute(1, true);
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   simple.Build();
   buildcc::base::m::TargetRunner(simple);
 }
@@ -59,8 +59,8 @@ TEST(TargetTestSourceOutOfRootGroup, Glob_OutOfRootSource) {
     simple.GlobSources(".."); // 6 files detected
     CHECK_EQUAL(6, simple.GetCurrentSourceFiles().size());
 
-    buildcc::m::CommandExpect_Execute(6, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(6, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
   }
@@ -77,8 +77,8 @@ TEST(TargetTestSourceOutOfRootGroup, GlobAbsolute_OutOfRootSource) {
         OUTOFROOT, buildcc::base::TargetType::Executable, gcc, "");
     simple.GlobSourcesAbsolute(fs::path(BUILD_SCRIPT_SOURCE) /
                                "data"); // 6 files detected
-    buildcc::m::CommandExpect_Execute(6, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(6, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     simple.Build();
     buildcc::base::m::TargetRunner(simple);
   }
diff --git a/buildcc/lib/target/test/target/test_target_user_deps.cpp b/buildcc/lib/target/test/target/test_target_user_deps.cpp
index f1f2d491..3e57f382 100644
--- a/buildcc/lib/target/test/target/test_target_user_deps.cpp
+++ b/buildcc/lib/target/test/target/test_target_user_deps.cpp
@@ -42,8 +42,8 @@ TEST(TargetTestUserDepsGroup, Target_Build_CompileDeps_NoChange) {
   compileDep.AddSource("dummy_main.cpp");
   compileDep.AddCompileDependency("new_source.cpp");
 
-  buildcc::m::CommandExpect_Execute(1, true);
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   compileDep.Build();
   buildcc::base::m::TargetRunner(compileDep);
 
@@ -57,8 +57,8 @@ TEST(TargetTestUserDepsGroup, Target_Build_LinkDeps_NoChange) {
   linkDep.AddSource("dummy_main.cpp");
   linkDep.AddLinkDependency("new_source.cpp");
 
-  buildcc::m::CommandExpect_Execute(1, true);
-  buildcc::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
+  buildcc::env::m::CommandExpect_Execute(1, true);
   linkDep.Build();
   buildcc::base::m::TargetRunner(linkDep);
 
@@ -73,8 +73,8 @@ TEST(TargetTestUserDepsGroup, Target_Build_CompileDeps_Rebuild) {
     compileDep.AddSource("dummy_main.cpp");
     compileDep.AddCompileDependency("new_source.cpp");
 
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     compileDep.Build();
     buildcc::base::m::TargetRunner(compileDep);
   }
@@ -95,8 +95,8 @@ TEST(TargetTestUserDepsGroup, Target_Build_CompileDeps_Rebuild) {
     compileDep.AddCompileDependency("new_source.cpp");
 
     buildcc::base::m::TargetExpect_PathUpdated(1, &compileDep);
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     compileDep.Build();
     buildcc::base::m::TargetRunner(compileDep);
   }
@@ -112,8 +112,8 @@ TEST(TargetTestUserDepsGroup, Target_Build_LinkDeps_Rebuild) {
     linkDep.AddSource("dummy_main.cpp");
     linkDep.AddLinkDependency("new_source.cpp");
 
-    buildcc::m::CommandExpect_Execute(1, true);
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     linkDep.Build();
     buildcc::base::m::TargetRunner(linkDep);
   }
@@ -134,7 +134,7 @@ TEST(TargetTestUserDepsGroup, Target_Build_LinkDeps_Rebuild) {
     linkDep.AddLinkDependency("new_source.cpp");
 
     buildcc::base::m::TargetExpect_PathUpdated(1, &linkDep); // Only link
-    buildcc::m::CommandExpect_Execute(1, true);
+    buildcc::env::m::CommandExpect_Execute(1, true);
     linkDep.Build();
     buildcc::base::m::TargetRunner(linkDep);
   }
diff --git a/buildcc/lib/toolchain/CMakeLists.txt b/buildcc/lib/toolchain/CMakeLists.txt
index 346fe175..edb0cc09 100644
--- a/buildcc/lib/toolchain/CMakeLists.txt
+++ b/buildcc/lib/toolchain/CMakeLists.txt
@@ -15,7 +15,6 @@ if (${TESTING})
     target_link_options(mock_toolchain PUBLIC ${TEST_LINK_FLAGS} ${BUILD_LINK_FLAGS})
     target_link_libraries(mock_toolchain PUBLIC
         mock_env
-        mock_command
 
         CppUTest
         CppUTestExt
@@ -55,7 +54,6 @@ if(${BUILDCC_BUILD_AS_INTERFACE})
     )
     target_link_libraries(toolchain PUBLIC 
         env
-        command
     )
 endif()
 
diff --git a/buildcc/lib/toolchain/src/api/toolchain_verify.cpp b/buildcc/lib/toolchain/src/api/toolchain_verify.cpp
index 943017fc..71048ec4 100644
--- a/buildcc/lib/toolchain/src/api/toolchain_verify.cpp
+++ b/buildcc/lib/toolchain/src/api/toolchain_verify.cpp
@@ -27,7 +27,7 @@
 #include "env/host_os_util.h"
 #include "env/util.h"
 
-#include "command/command.h"
+#include "env/command.h"
 
 namespace {
 // Constants
@@ -47,9 +47,9 @@ std::vector<std::string> ParseEnvVarToPaths(const std::string &env_var) {
   return paths;
 }
 
-std::string GetGccCompilerVersion(const buildcc::Command &command) {
+std::string GetGccCompilerVersion(const buildcc::env::Command &command) {
   std::vector<std::string> stdout_data;
-  bool executed = buildcc::Command::Execute(
+  bool executed = buildcc::env::Command::Execute(
       command.Construct("{compiler} -dumpversion"), {}, &stdout_data);
   buildcc::env::assert_fatal(
       executed, "GetCompilerVersion command not executed successfully");
@@ -69,7 +69,7 @@ std::string GetMsvcCompilerVersion() {
 std::optional<std::string>
 GetCompilerVersion(const fs::path &absolute_path,
                    const buildcc::base::Toolchain &toolchain) {
-  buildcc::Command command;
+  buildcc::env::Command command;
   command.AddDefaultArgument(
       "compiler",
       (absolute_path / toolchain.GetCppCompiler()).make_preferred().string());
@@ -93,9 +93,9 @@ GetCompilerVersion(const fs::path &absolute_path,
   return compiler_version;
 }
 
-std::string GetGccTargetArchitecture(const buildcc::Command &command) {
+std::string GetGccTargetArchitecture(const buildcc::env::Command &command) {
   std::vector<std::string> stdout_data;
-  bool executed = buildcc::Command::Execute(
+  bool executed = buildcc::env::Command::Execute(
       command.Construct("{compiler} -dumpmachine"), {}, &stdout_data);
   buildcc::env::assert_fatal(
       executed, "GetCompilerArchitecture command not executed successfully");
@@ -119,7 +119,7 @@ std::string GetMsvcTargetArchitecture() {
 std::optional<std::string>
 GetCompilerArchitecture(const fs::path &absolute_path,
                         const buildcc::base::Toolchain &toolchain) {
-  buildcc::Command command;
+  buildcc::env::Command command;
   command.AddDefaultArgument(
       "compiler",
       (absolute_path / toolchain.GetCppCompiler()).make_preferred().string());
diff --git a/buildcc/lib/toolchain/test/test_toolchain_verify.cpp b/buildcc/lib/toolchain/test/test_toolchain_verify.cpp
index cda14c8b..4a92e7cc 100644
--- a/buildcc/lib/toolchain/test/test_toolchain_verify.cpp
+++ b/buildcc/lib/toolchain/test/test_toolchain_verify.cpp
@@ -32,8 +32,8 @@ TEST(ToolchainTestGroup, VerifyToolchain_Gcc) {
 
   std::vector<std::string> version_stdout_data{"version"};
   std::vector<std::string> arch_stdout_data{"arch"};
-  buildcc::m::CommandExpect_Execute(1, true, &version_stdout_data);
-  buildcc::m::CommandExpect_Execute(1, true, &arch_stdout_data);
+  buildcc::env::m::CommandExpect_Execute(1, true, &version_stdout_data);
+  buildcc::env::m::CommandExpect_Execute(1, true, &arch_stdout_data);
 
   std::string putenv_str = fmt::format("CUSTOM_BUILDCC_PATH={}/toolchains/gcc",
                                        fs::current_path().string());
@@ -62,8 +62,8 @@ TEST(ToolchainTestGroup, VerifyToolchain_Clang) {
 
   std::vector<std::string> version_stdout_data{"version"};
   std::vector<std::string> arch_stdout_data{"arch"};
-  buildcc::m::CommandExpect_Execute(1, true, &version_stdout_data);
-  buildcc::m::CommandExpect_Execute(1, true, &arch_stdout_data);
+  buildcc::env::m::CommandExpect_Execute(1, true, &version_stdout_data);
+  buildcc::env::m::CommandExpect_Execute(1, true, &arch_stdout_data);
 
   std::string putenv_str = fmt::format(
       "CUSTOM_BUILDCC_PATH={}/toolchains/clang", fs::current_path().string());
@@ -177,7 +177,7 @@ TEST(ToolchainTestGroup, VerifyToolchain_PathContainsDir) {
 }
 
 int main(int ac, char **av) {
-  buildcc::m::VectorStringCopier copier;
+  buildcc::env::m::VectorStringCopier copier;
   mock().installCopier(TEST_VECTOR_STRING_TYPE, copier);
 
   // NOTE, Check the GCC, MSVC and Clang compilers
diff --git a/buildcc/plugins/src/clang_compile_commands.cpp b/buildcc/plugins/src/clang_compile_commands.cpp
index 33207cdb..10e103fb 100644
--- a/buildcc/plugins/src/clang_compile_commands.cpp
+++ b/buildcc/plugins/src/clang_compile_commands.cpp
@@ -65,7 +65,7 @@ void ClangCompileCommands::Generate() {
       // DONE, Get std::vector<std::string> CompileCommand
       // DONE, Get intermediate directory from env
       std::string sf = fmt::format("{}", source);
-      std::string command = t->GetCompileCommand(source);
+      const std::string &command = t->GetCompileCommand(source);
       std::string directory = fmt::format("{}", env::get_project_build_dir());
 
       std::string temp = fmt::format(
diff --git a/doc/software_architecture/buildcc_interface_lib.PNG b/doc/software_architecture/buildcc_interface_lib.PNG
index 59385d6b..e2cc97aa 100644
Binary files a/doc/software_architecture/buildcc_interface_lib.PNG and b/doc/software_architecture/buildcc_interface_lib.PNG differ