diff --git a/daggy/include/daggy/Utilities.hpp b/daggy/include/daggy/Utilities.hpp
index 9d8af8f..aba7bef 100644
--- a/daggy/include/daggy/Utilities.hpp
+++ b/daggy/include/daggy/Utilities.hpp
@@ -14,6 +14,8 @@
 #include "DAG.hpp"
 
 namespace daggy {
+    std::string globalSub(std::string string, const std::string &pattern, const std::string &replacement);
+
     std::vector<Command> expandCommands(const std::vector<std::string> &command, const ParameterValues &parameters);
 
     DAG buildDAGFromTasks(const std::vector<Task> &tasks);
diff --git a/daggy/src/Utilities.cpp b/daggy/src/Utilities.cpp
index 62a8919..8bd00fe 100644
--- a/daggy/src/Utilities.cpp
+++ b/daggy/src/Utilities.cpp
@@ -3,28 +3,47 @@
 #include <daggy/Utilities.hpp>
 
 namespace daggy {
+    std::string globalSub(std::string string, const std::string &pattern, const std::string &replacement) {
+        size_t pos = string.find(pattern);
+        while (pos != std::string::npos) {
+            string.replace(pos, pattern.size(), replacement);
+            pos = string.find(pattern);
+        }
+        return string;
+    }
+
     std::vector<std::vector<std::string>>
     expandCommands(const std::vector<std::string> &command, const ParameterValues &parameters) {
         std::vector<std::vector<std::string>> commands{{}};
 
         for (const auto &part : command) {
-            // this isn't an interpolated value
-            if (parameters.find(part) == parameters.end()) {
-                for (auto &cmd : commands) cmd.push_back(part);
-                continue;
-            }
-            auto &inVal = parameters.at(part);
-            if (std::holds_alternative<std::string>(inVal)) {
-                for (auto &cmd : commands) cmd.push_back(std::get<std::string>(inVal));
-                continue;
+            std::vector<std::string> expandedPart;
+
+            for (const auto &[param, paramValue] : parameters) {
+                auto pos = part.find(param);
+                if (pos == std::string::npos) continue;
+                std::vector<std::string> newExpandedPart;
+
+                if (std::holds_alternative<std::string>(paramValue)) {
+                    for (auto &cmd : expandedPart) {
+                        newExpandedPart.push_back(globalSub(cmd, param, std::get<std::string>(paramValue)));
+                    }
+                } else {
+                    for (const auto &val : std::get<std::vector<std::string>>(paramValue)) {
+                        for (auto cmd : expandedPart) {
+                            newExpandedPart.push_back(globalSub(cmd, param, val));
+                        }
+                    }
+                }
+
+                expandedPart.swap(newExpandedPart);
             }
 
-            // Ends up being expensive, as it's a cartesian product
             std::vector<std::vector<std::string>> newCommands;
-            for (const auto &val : std::get<std::vector<std::string>>(inVal)) {
+            for (const auto &newPart : expandedPart) {
                 for (auto cmd : commands) {
-                    cmd.push_back(val);
-                    newCommands.push_back(cmd);
+                    cmd.push_back(newPart);
+                    newCommands.emplace_back(cmd);
                 }
             }
             commands.swap(newCommands);
@@ -136,4 +155,4 @@ namespace daggy {
         os << std::put_time(std::localtime(&t_c), "%Y-%m-%d %H:%M:%S %Z");
         return os;
     }
-}
\ No newline at end of file
+}
diff --git a/tests/unit_utilities.cpp b/tests/unit_utilities.cpp
index c5b9329..e1fc3eb 100644
--- a/tests/unit_utilities.cpp
+++ b/tests/unit_utilities.cpp
@@ -2,6 +2,10 @@
 #include <filesystem>
 #include <fstream>
 
+#include <iomanip>
+#include <algorithm>
+#include <iostream>
+
 #include <catch2/catch.hpp>
 
 #include "daggy/Utilities.hpp"
@@ -9,6 +13,12 @@
 #include "daggy/executors/task/ForkingTaskExecutor.hpp"
 #include "daggy/loggers/dag_run/OStreamLogger.hpp"
 
+TEST_CASE("String Utilities", "[utilities_string]") {
+    std::string test = "/this/is/{{A}}/test/{{A}}";
+    auto res = daggy::globalSub(test, "{{A}}", "hello");
+    REQUIRE(res == "/this/is/hello/test/hello");
+}
+
 TEST_CASE("Parameter Expansion", "[utilities_parameter_expansion]") {
     SECTION("Basic expansion") {
         std::string testParams{R"({"DATE": ["2021-05-06", "2021-05-07" ], "SOURCE": "name", "TYPE": ["a", "b", "c"]})"};
@@ -28,6 +38,22 @@ TEST_CASE("Parameter Expansion", "[utilities_parameter_expansion]") {
         // TYPE isn't used, so it's just |DATE| * |SOURCE|
         REQUIRE(allCommands.size() == 2);
     }
+
+    SECTION("Expand within a command part") {
+        std::string testParams{
+                R"({"DATE": ["2021-05-06", "2021-05-07" ], "SOURCE": ["A", "B"], "TYPE": ["a", "b", "c"]})"};
+        auto params = daggy::parametersFromJSON(testParams);
+        std::vector<std::string> cmd{"/usr/bin/touch", "/tmp/{{DATE}}_{{SOURCE}}"};
+        auto result = daggy::expandCommands(cmd, params);
+
+        // TYPE isn't used, so it's just |DATE| * |SOURCE|
+        REQUIRE(result.size() == 4);
+
+        for (const auto &command : result) {
+            std::copy(command.begin(), command.end(), std::ostream_iterator<std::string>(std::cout, " "));
+            std::cout << std::endl;
+        }
+    }
 }
 
 TEST_CASE("DAG Runner", "[utilities_dag_runner]") {
@@ -41,4 +67,4 @@ TEST_CASE("DAG Runner", "[utilities_dag_runner]") {
 
     auto runID = logger.startDAGRun("test_run", tasks);
     daggy::runDAG(runID, tasks, ex, logger, dag);
-}
\ No newline at end of file
+}