set "_os=64" if "%PROCESSOR_ARCHITECTURE%"=="x86" (if not defined PROCESSOR_ARCHITEW6432 set "_os=32") На основании: https://blogs.msdn.microsoft.com/david.wang/2006/03/27/howto-detect-process-bitness/ и http://ss64.com/nt/syntax-64bit.html
set "_os=64" if "%PROCESSOR_ARCHITECTURE%"=="x86" (if not defined PROCESSOR_ARCHITEW6432 set "_os=32")
На основании: https://blogs.msdn.microsoft.com/david.wang/2006/03/27/howto-detect-process-bitness/
и http://ss64.com/nt/syntax-64bit.html