diff --git a/bin/miaou-bash b/bin/miaou-bash
index 02eb3a3..0412aaa 100755
--- a/bin/miaou-bash
+++ b/bin/miaou-bash
@@ -4,6 +4,7 @@
 # constants
 
 MIAOU_DEBUG=${MIAOU_DEBUG:-false}
+MIAOU_ERROR_REGEX='^(.*): line ([0-9]+): miaou_error:'
 
 declare -A ANSI
 ANSI[RESET]=0
@@ -36,7 +37,7 @@ ANSI[BG_WHITE]=47
 ANSI[BG_GRAY]=90
 ANSI[BG_MAGENTA]=95
 
-readonly MIAOU_DEBUG ANSI
+readonly MIAOU_DEBUG MIAOU_ERROR_REGEX ANSI
 
 ## functions
 
@@ -139,8 +140,6 @@ function on_error {
   trap - RETURN
   failure_code="${1:-200}"
 
-  # >&4 printf '\r' # TODO: force carriage return explicitly, is it really useful?
-
   miaou_debug "<on_error code=${failure_code} command={${BASH_COMMAND}}>"
 
   if [[ $$ == "$BASHPID" ]]; then
@@ -310,7 +309,22 @@ function on_pipe {
 }
 
 function dump_stderr {
-  miaou_debug "<stderr count=${#tmp_error[@]}>"
+  local tmp_error_count=${#tmp_error[@]}
+  miaou_debug "<stderr count=${tmp_error_count}>"
+  if [[ -v MAIN_FD_MIAOU && $tmp_error_count -gt 0 && "$MAIN_FD_STDERR" == false ]]; then
+    miaou_debug "<main_fd_miaou/>"
+    local last_error="${tmp_error[-1]}"
+    if [[ "$last_error" =~ $MIAOU_ERROR_REGEX ]]; then
+      tmp_error_count=$((tmp_error_count - 1))
+      miaou_debug "<hide_latest_miaou_error line=${last_error} count=$tmp_error_count/>"
+      unset 'tmp_error[-1]'
+      if [[ $tmp_error_count == 0 ]]; then
+        # TODO: grab last_stdout and test no carriage_return, cf: ../test/stub/tee_last_line.bash
+        miaou_debug "<prevent_stdout_no_carriage_return />"
+        printf "\r"
+      fi
+    fi
+  fi
   tty_ansi FG_LIGHTBLUE
   for i in "${tmp_error[@]}"; do
     is_true "$CHILD_PROCESS" && miaou_debug "<childerr content={$i}/>"
@@ -431,13 +445,12 @@ function load_tmp_error {
       miaou_debug "<tmp_error empty/>"
     else
       miaou_debug "<tmp_error count=${count}>"
-      local i miaou_error_regex last_miaou_error_index=-1 content
+      local i last_miaou_error_index=-1 content
       local multiple_errors=()
-      miaou_error_regex='^(.*): line ([0-9]+): miaou_error:'
       for i in "${!tmp_error[@]}"; do
         content="${tmp_error[i]}"
         # miaou_debug "<tmperr index=$i content={$content}/>"
-        if [[ "$content" =~ $miaou_error_regex ]]; then
+        if [[ "$content" =~ $MIAOU_ERROR_REGEX ]]; then
           if [[ $last_miaou_error_index -ge 0 ]]; then
             multiple_errors+=("$last_miaou_error_index")
           fi
@@ -623,7 +636,13 @@ if is_true "$CHILD_PROCESS"; then
   miaou_debug "<child file=$BASH_ARGV0 pid=${BASHPID} parent=${PPID}>"
 else
   # the MAIN Process
-  [[ -e /proc/$$/fd/3 ]] && exec 4>&3 3>&- || exec 4>/dev/tty # swap fd 3 4 when fd 3 sent off
+  if [[ -e /proc/$$/fd/3 ]]; then
+    exec 4>&3 3>&- # swap fd 3 4 when fd 3 sent off
+  else
+    MAIN_FD_MIAOU=true
+    [[ -t 2 ]] && MAIN_FD_STDERR=false || MAIN_FD_STDERR=true
+    exec 4>/dev/tty
+  fi
   exec 3>/dev/stderr 2>"$MIAOU_BASH_ERROR"
   miaou_debug "<main file=$BASH_ARGV0 pid=${BASHPID}/>"
 fi
diff --git a/test/miaou-bash.test.bash b/test/miaou-bash.test.bash
index 3425c53..0c62c54 100755
--- a/test/miaou-bash.test.bash
+++ b/test/miaou-bash.test.bash
@@ -41,6 +41,7 @@ function assert_grep {
   failures+=("$cmd $safe_args")
   return 1
 }
+
 function fail_type {
   ((test_count++))
   local success regex hint_message
@@ -68,7 +69,24 @@ function fail_type {
   failures+=("$cmd")
   return 1
 }
+function fail_stderr_count {
+  ((test_count++))
+  local regex count="$2"
 
+  cmd="./test/stub/scenario.bash $1"
+  # mapfile -t stderr <<<"$(miaou-bash ./test/stub/scenario.bash "$1" 2>&1 >/dev/null 3>/dev/null)"
+  if ! $cmd >/dev/null 2>_stderr 3>/dev/null; then
+    mapfile -t stderr <_stderr
+    if [[ "${#stderr[@]}" == "$count" ]]; then
+      echo -n .
+      return
+    fi
+  fi
+
+  echo -n F
+  failures+=("$cmd 2>_stderr")
+  return 1
+}
 # main
 
 set -uo pipefail
@@ -95,6 +113,9 @@ time {
   fail_type source_not_found SOURCE_NOT_FOUND
   fail_type file_not_found FILE_NOT_FOUND
   fail_type child_error CHILD_ERROR 'prefer source than child process'
+
+  fail_stderr_count unbound_variable 1
+  fail_stderr_count child_error 4
 }
 failed=${#failures[@]}
 success=$((test_count - failed))
diff --git a/test/stub/extra/onemore.bash b/test/stub/extra/onemore.bash
index 4e3e042..5f6ee74 100755
--- a/test/stub/extra/onemore.bash
+++ b/test/stub/extra/onemore.bash
@@ -1,5 +1,4 @@
 #!/usr/bin/env miaou-bash
-#!/usr/bin/env bash
 
 function onemore {
   echo onemore loaded
diff --git a/test/stub/scenario.bash b/test/stub/scenario.bash
index ade21ee..e76ac3c 100755
--- a/test/stub/scenario.bash
+++ b/test/stub/scenario.bash
@@ -71,7 +71,7 @@ function do_false {
 
 function do_success {
   echo "count args: $#"
-  [[ true==true ]] && echo true
+  [[ true != 'false' ]] && echo true
   ! false && echo unfalse
   return
 }
@@ -89,6 +89,8 @@ function do_success_with_args {
 function do_unbound_variable {
   a=5
   echo -n "content: "
+  # >&2 echo err1
+  # echo "content: "
   echo -n "a=${a} b=${b}"
 }