diff --git a/command.cpp b/command.cpp
index 0bea643..a89a120 100644
--- a/command.cpp
+++ b/command.cpp
@@ -107,6 +107,9 @@ namespace {
 	}
 
 
+	bool is_script(const fs::path &path) {
+		return path.extension() == ".text";
+	}
 }
 
 
@@ -359,8 +362,6 @@ int simple_command::execute(Environment &env, const fdmask &fds, bool throwup) {
 			return status;
 		}
 
-		if (env.test()) return 0;
-
 		if (env.startup()) {
 			fprintf(stderr, "### MPW Shell - startup file may not contain external commands.\n");
 			return 0;
@@ -374,6 +375,23 @@ int simple_command::execute(Environment &env, const fdmask &fds, bool throwup) {
 			//fprintf(stderr, "### MPW Shell - Command \"%s\" was not found.\n", name.c_str());
 			//return -1;
 		}
+
+		if (is_script(path)) {
+			// scripts run with an isolated environment.
+			Environment new_env = env.subshell_environment();
+			new_env.set("command", path);
+			new_env.set_argv(path, p.arguments);
+
+			try {
+				return read_file(new_env, path, newfds);
+			} catch (const exit_command_t &ex) {
+				return ex.value;
+			}
+		}
+
+
+		if (env.test()) return 0;
+
 		env.set("command", path);
 		p.arguments[0] = path;
 
diff --git a/environment.cpp b/environment.cpp
index b6e816b..2b602c7 100644
--- a/environment.cpp
+++ b/environment.cpp
@@ -23,6 +23,10 @@ namespace {
 
 	bool tf(long v) { return v; }
 
+	bool tf(const EnvironmentEntry &e) {
+		return tf(static_cast<std::string>(e));
+	}
+
 	// used for #.  base 10 only, extra chars ignored.
 	int to_pound_int(const std::string &s) {
 		if (s.empty()) return 0;
@@ -38,6 +42,29 @@ namespace {
 
 }
 
+
+	Environment Environment::subshell_environment() {
+		/* clone the current environment, do not include local variables */
+		Environment env;
+		env._alias_table = _alias_table;
+		
+		auto &table = env._table;
+		for (const auto &kv : _table) {
+			const auto &k = kv.first;
+			const auto &value = kv.second;
+			if (!value) continue;
+
+			if (k == "echo") env._echo = tf(value);
+			if (k == "exit") env._exit = tf(value);
+			if (k == "test") env._test = tf(value);
+
+			table.emplace_hint(table.end(), k, value);
+		}
+
+		return env;
+	}
+
+
 	std::string Environment::get(const std::string & key) const {
 		auto iter = find(key);
 		if (iter == end()) return "";
diff --git a/environment.h b/environment.h
index 556de7c..f3cbfe2 100644
--- a/environment.h
+++ b/environment.h
@@ -56,7 +56,8 @@ public:
 	typedef std::vector<std::pair<std::string, std::string>> alias_table_type;
 	typedef alias_table_type::const_iterator const_alias_iterator;
 
-	//const EnvironmentEntry & lookup(const std::string &s);
+
+	Environment subshell_environment();
 
 	void set_argv(const std::string &argv0, const std::vector<std::string>& argv);
 	void set_argv(const std::vector<std::string>& argv);
@@ -80,10 +81,6 @@ public:
 	bool startup() const noexcept { return _startup; }
 	void startup(bool tf) noexcept { _startup = tf; }
 
-
-	bool passthrough() const noexcept { return _passthrough; }
-	void passthrough(bool tf) noexcept { _passthrough = tf; }
-
 	template<class FX>
 	void foreach(FX && fx) { for (const auto &kv : _table) { fx(kv.first, kv.second); }}
 
@@ -133,8 +130,6 @@ public:
 private:
 	// magic variables.
 
-	friend class indent_helper;
-
 	int _indent = 0;
 	int _loop = 0;
 
@@ -145,7 +140,6 @@ private:
 	int _status = 0;
 	int _pound = 0;
 	bool _startup = false;
-	bool _passthrough = false;
 
 	void set_common(const std::string &, const std::string &, bool);
 	void rebuild_aliases();
@@ -155,16 +149,5 @@ private:
 	alias_table_type _alias_table;
 };
 
-/*
-class indent_helper {
-public:
-	indent_helper(Environment &e) : env(e) { env._indent++; }
-	void release() { if (active) { active = false; env._indent--; }}
-	~indent_helper() { if (active) env._indent--; }
-private:
-	Environment &env;
-	bool active = true;
-};
-*/
 
 #endif