This program will run "smartctl.exe -n standby X:" on all HDD drives in an unattended manner.

HDD_StandBy_Check.bat

:: BatchGotAdmin <https://sites.google.com/site/eneerge/scripts/batchgotadmin>
:-------------------------------------
@echo off
REM  --> Check for permissions
>nul 2>&1 "%SYSTEMROOT%\system32\cacls.exe" "%SYSTEMROOT%\system32\config\system"

REM --> If error flag set, we do not have admin.
if '%errorlevel%' NEQ '0' (
    echo Requesting administrative privileges...
    goto UACPrompt
) else ( goto gotAdmin )

:UACPrompt
    echo Set UAC = CreateObject^("Shell.Application"^) > "%temp%\getadmin.vbs"
    echo UAC.ShellExecute "%~s0", "", "", "runas", 1 >> "%temp%\getadmin.vbs"

    "%temp%\getadmin.vbs"
    exit /B

:gotAdmin
    if exist "%temp%\getadmin.vbs" ( del "%temp%\getadmin.vbs" )
    pushd "%CD%"
    CD /D "%~dp0"
    @echo on
:--------------------------------------


:: StandBy Checker::PrintInfo <[email protected]> (c) 2015 BSD-Clause 3
:--------------------------------------
@echo off
echo.
echo == Disk StandBy Checker ==
echo   (C) 2024 "<[email protected]>" BSD-Clause 3
echo.
echo   This program will run "smartctl.exe -n standby X:" on all HDD drives in an unattended manner.
echo.
echo   Press ANY KEY to continue...
echo.
pause>nul
:--------------------------------------


:: StandBy Checker <[email protected] (c) 2014-2015 BSD-Clause 3>
:--------------------------------------
@echo off
setlocal enabledelayedexpansion
REM ^, -- ^ is the escape character for declarations  between '
echo checking.....(a SPINNING drive reports: Device is in ACTIVE or IDLE mode)
for /f "skip=1" %%a in ('wmic logicaldisk get caption') do (
    set isHDD=
    for /f "tokens=*" %%i in ('smartctl.exe -a %%a ^| findstr "Rotation Rate:"') do set isHDD=%%i
    if not "!isHDD!"=="" (
        echo.!isHDD!| find /i "rpm">nul && (
            echo | set /p="%%a "
            smartctl.exe -n standby %%a | findstr "Device"
        )
    )
)
:--------------------------------------

smartctl.exe -a %%a will wakeup sleep disk, so this script is useless.

::smartctl.exe -s standby,now d:
::smartctl 6.5 2016-05-07 r4318 [x86_64-w64-mingw32-win10] (sf-6.5-1)
::Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org

::Device placed in STANDBY mode