diff --git a/bin/bash-back b/bin/bash-back
index e4adbb2..b46c359 100755
--- a/bin/bash-back
+++ b/bin/bash-back
@@ -76,6 +76,7 @@ function on_exit {
       stack_summary+=("ERROR $code: [$message]")
     else
       # TODO: if last_error is a detected stacktrace, grab as so
+      # pstree -as $$ => parent contains bash-back?
       stack_summary+=("ERROR $code: <undefined>")
     fi
 
diff --git a/useless.sh b/useless.sh
index 962d88b..9ff73b8 100755
--- a/useless.sh
+++ b/useless.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash-back
 
 function F2 {
   echo "stdout A"
@@ -31,7 +31,7 @@ function F3 {
 
 echo start of useless
 F3
-# lib/utility.bash
+lib/utility.bash
 # . lib/utility.bash
 
 # >&2 echo some trace in stderr