diff --git a/include/hack.hpp b/include/hack.hpp
index e778cb11..31993cb6 100644
--- a/include/hack.hpp
+++ b/include/hack.hpp
@@ -23,7 +23,7 @@ namespace hack
 
 extern std::mutex command_stack_mutex;
 std::stack<std::string> &command_stack();
-void ExecuteCommand(const std::string command);
+void ExecuteCommand(const std::string &command);
 
 extern bool game_shutdown;
 extern bool shutdown;
diff --git a/src/hack.cpp b/src/hack.cpp
index da0a09b0..b192a912 100644
--- a/src/hack.cpp
+++ b/src/hack.cpp
@@ -94,7 +94,7 @@ std::stack<std::string> &hack::command_stack()
     return stack;
 }
 
-void hack::ExecuteCommand(const std::string command)
+void hack::ExecuteCommand(const std::string &command)
 {
     std::lock_guard<std::mutex> guard(hack::command_stack_mutex);
     hack::command_stack().push(command);