✨ add template get/convert for ghost

test/for_subprocess_test/infinite_loop.nas

@@ -0,0 +1,11 @@
+use std.unix;
+
+var count = 0;
+while(1) {
+    unix.sleep(0.1);
+    count += 0.1;
+    println("process running time: ", count);
+    if (count > 2) {
+        die("test failed");
+    }
+}

test/subprocess_test.nas

@@ -0,0 +1,13 @@
+use std.subprocess;
+use std.unix;
+
+var process = subprocess.create([
+    "./nasal",
+    "test/for_subprocess_test/infinite_loop.nas"
+]);
+
+unix.sleep(1);
+
+println("kill subprocess...");
+var res = subprocess.terminate(process);
+println("subprocess killed, code ", res);