diff --git a/CMakeLists.txt b/CMakeLists.txt
index 10dd5f17..2e2bfb9a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,6 +10,7 @@ set(CMAKE_EXPORT_COMPILE_COMMANDS 1)
 include_directories("include/")
 include_directories("vendor/")
 
+
 # CMark
 link_directories("vendor/cmark")
 
@@ -30,8 +31,8 @@ if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
     ########################
 
     # Add back: fsanitize=leak
-    set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG}  -fasynchronous-unwind-tables -ggdb3 -Wall  -fsanitize=leak -fsanitize=address -fsanitize=undefined -fno-omit-frame-pointer -flto=auto")
-    set(CMAKE_LINKER_FLAGS_DEBUG "${CMAKE_LINKER_FLAGS_DEBUG} -fsanitize=leak -fsanitize=address -fsanitize=undefined -no-pie -Wall -fno-omit-frame-pointer")
+    set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG}  -fsanitize=address,leak,undefined -fno-omit-frame-pointer -fasynchronous-unwind-tables -no-pie -ggdb3 -Wall -flto=auto")
+    set(CMAKE_LINKER_FLAGS_DEBUG "${CMAKE_LINKER_FLAGS_DEBUG} -fsanitize=address,leak,undefined -fno-omit-frame-pointer -no-pie -Wall -fno-omit-frame-pointer")
 
     ########################
     # RELEASE              #
@@ -57,10 +58,17 @@ else ()
     # Executable
     add_executable(fan ${SRC_FILES})
 
+    # Link libasan only for debug builds
+#    if(CMAKE_BUILD_TYPE MATCHES Debug)
+#        target_link_libraries(fan PRIVATE asan)
+#    endif()
+
 
     # Final Build
     target_link_libraries(fan-dev PRIVATE ${CMAKE_CXX_STANDARD_LIBRARIES} pthread ${CURL_LIBRARIES} cmark) #leveldb
     target_link_libraries(fan PRIVATE ${CMAKE_CXX_STANDARD_LIBRARIES} fan-dev)
+
+
 endif()
 
 # Static Lib
diff --git a/src/vm/std/os.cpp b/src/vm/std/os.cpp
index 9cdba183..12595a3a 100644
--- a/src/vm/std/os.cpp
+++ b/src/vm/std/os.cpp
@@ -25,7 +25,7 @@ void lib::os::getEnv(WrenVM* vm) {
 	const char* key = wrenGetSlotString(vm, 1);
 	auto val = std::getenv(key);
 	wrenEnsureSlots(vm, 1);
-	if (val == NULL) {
+	if (val == nullptr) {
 		wrenSetSlotNull(vm, 0);
 	} else {
 		wrenSetSlotString(vm, 0, val);
@@ -103,7 +103,7 @@ double getParentProcessId() {
 	return 0;  // Parent process not found.
 #else
 	pid_t ppid = getppid();
-	double dPpid = static_cast<double>(ppid);
+	auto dPpid = static_cast<double>(ppid);
 	return dPpid;
 #endif
 }
@@ -155,7 +155,7 @@ constexpr std::string_view vm::getPlatformArchitecture() {
 void lib::os::runtimeOS(WrenVM* vm) {
 	wrenEnsureSlots(vm, 1);
 	auto os = vm::getOperatingSystem();
-	if (os != "uknown") {
+	if (os != "unknown") {
 		wrenSetSlotString(vm, 0, os.data());
 	} else {
 		wrenSetSlotNull(vm, 0);
@@ -183,7 +183,7 @@ void lib::os::processExec(WrenVM* vm) {
 	for (int i = 0; i < argsLen; i++) {
 		wrenGetListElement(vm, 2, i, 4);
 		auto arg = wrenGetSlotString(vm, 4);
-		args.push_back(arg);
+		args.emplace_back(arg);
 	}
 
 	std::string parsedArgs = boost::algorithm::join(args, " ");
diff --git a/tests/std/exec.fan b/tests/std/exec.fan
new file mode 100644
index 00000000..e658b1f9
--- /dev/null
+++ b/tests/std/exec.fan
@@ -0,0 +1,5 @@
+import "std/os" for Process
+
+var out = Process.exec("eval", ["echo", "-n", "hi, there", "|", "sha256sum"])
+
+System.print(out)
\ No newline at end of file
diff --git a/valgrind.sh b/valgrind.sh
index d81d2271..1159b1a9 100755
--- a/valgrind.sh
+++ b/valgrind.sh
@@ -3,16 +3,18 @@
 # Check for the existence of the fan executable in different directories
 if [[ -x "./build/debug/fan" ]]; then
     FAN_EXEC="./build/debug/fan"
-elif [[ -x "./build/release/fan" ]]; then
-    FAN_EXEC="./build/release/fan"
+#elif [[ -x "./build/release/fan" ]]; then
+#    FAN_EXEC="./build/release/fan"
 else
     FAN_EXEC="./build/fan"
 fi
 
+export LD_PRELOAD="/usr/lib/x86_64-linux-gnu/libasan.so.6:$LD_PRELOAD"
+
 FAN_LIB=./lang valgrind --leak-check=full \
          --show-leak-kinds=all \
          --track-origins=yes \
          --verbose \
          --leak-check=full \
          --log-file=build/valgrind-out.txt \
-         $(FAN_EXEC) $@
+         $FAN_EXEC $@