[anonymous_prodject]

Вот, неужели, сделал рабочий прототип. Спасибо.

Код:

@echo off
setlocal enabledelayedexpansion
<"setting.xml" (for /f "tokens=2 delims=>< " %%a in ('find "<GoogleUsername>"') do @echo %%a)
pause > nul

echo enter mail:
Set /p sz=

set "sf=<GoogleUsername>" &: Поиск строки "<GoogleUsername>username</GoogleUsername>"
<"setting.xml">>$ (for /f "delims=" %%a in ('more') do echo "%%a"|>nul find/i "%sf%" && (
   for /f "tokens=1-3 delims=>< " %%b in ("%%~a") do set "z=%%c"& echo:  ^<%%b^>!z:%%c=%sz%!^<%%d^>
  ) || (
   echo %%a
  )
 )
)
move $ "setting.xml"