diff --git a/index.mjs b/index.mjs
index 6d6c0864d5..ff806a4bc5 100644
--- a/index.mjs
+++ b/index.mjs
@@ -111,6 +111,7 @@ export function $(pieces, ...args) {
     promise.child = child
     if (promise._postrun) promise._postrun()
   }
+  setTimeout(promise._run, 0) // Make sure all subprocesses started.
   return promise
 }