@echo off & setlocal enableextensions
  ::
  if "%~1"=="" (
    echo Usage: %~0 .extension
    goto :EOF
    )
  set ext_=%~1
  ::
  echo %ext_%|find "=" > nul
  if %errorlevel% EQU 0 (
    echo Equal signs not allowed for safety reasons in %ext_%
    goto :EOF
    )
  ::
  for /f "tokens=2 delims==" %%a in (
    'assoc^|find /i "%ext_%"') do set assoc_=%%a
  echo %ext_% %assoc_%
  ::
  if defined assoc_ (
    reg query HKLM\SOFTWARE\Classes\%assoc_%|find "REG_SZ"
    echo.
    reg query HKLM\SOFTWARE\Classes\%assoc_%\shell|find "shell\"
    echo.
    for /f "tokens=1* delims==" %%a in ('assoc %ext_%') do ftype %%b
    ) else (
    echo No association)
  ::
  endlocal & goto :EOF