Is there any easy way to get 2 days ago date using

Question

I am trying to change the code in order to get two days ago date using the batch file. In this example, I can take today date

for /f "tokens=2 delims==" %%I in ('wmic os get localdatetime /format:list') do set datetime=%%I
set LogDateTime=%datetime:~0,8%_%datetime:~8,6%

However, I don't know how to modify the code to get two days ago data. I am not looking for PowerShell, and not any other solution. We have to use only the batch.

Answer 1

You need to convert the date into a Julian Date to do date math in batch files. Here are two function. One to get the current date and then one to do that date math.

@echo off
setlocal

REM Get the current date
REM Will return variables YY, YYYY, MM, DD, HH, Min and Sec
Call :GetDateTime

REM Add or Subtract from the current date
REM Must use + or - symbol
REM Revised date will be assigned to RetVar
Call :AddSubDate %YYYY% %MM% %DD% -2 past

echo Past     : %past%
pause
GOTO :EOF

:AddSubDate Year Month Day <+/-Days> RetVar
setlocal & set a=%4
set "yy=%~1"&set "mm=%~2"&set "dd=%~3"
set /a "yy=10000%yy% %%10000,mm=100%mm% %% 100,dd=100%dd% %% 100"
if %yy% LSS 100 set /a yy+=2000 &rem Adds 2000 to two digit years
set /a JD=dd-32075+1461*(yy+4800+(mm-14)/12)/4+367*(mm-2-(mm-14)/12*12)/12-3*((yy+4900+(mm-14)/12)/100)/4
if %a:~0,1% equ + (set /a JD=%JD%+%a:~1%) else set /a JD=%JD%-%a:~1%
set /a L= %JD%+68569,     N= 4*L/146097, L= L-(146097*N+3)/4, I= 4000*(L+1)/1461001
set /a L= L-1461*I/4+31, J= 80*L/2447,  K= L-2447*J/80,      L= J/11
set /a J= J+2-12*L,      I= 100*(N-49)+I+L
set /a YYYY= I, MM=100+J, DD=100+K
set MM=%MM:~-2% & set DD=%DD:~-2%
set ret=%YYYY: =%%MM: =%%DD: =%
endlocal & set %~5=%ret%
exit /b

:GetDateTime Year Month Day Hour Minute Second
@echo off & setlocal
for /f "tokens=2 delims==" %%a in ('wmic OS Get localdatetime /value') do set "dt=%%a"
set "YY=%dt:~2,2%" & set "YYYY=%dt:~0,4%" & set "MM=%dt:~4,2%" & set "DD=%dt:~6,2%"
set "HH=%dt:~8,2%" & set "Min=%dt:~10,2%" & set "Sec=%dt:~12,2%"
( ENDLOCAL
   set "YY=%YY%" 
   set "YYYY=%YYYY%" 
   set "MM=%MM%" 
   set "DD=%DD%"
   set "HH=%HH%" 
   set "Min=%Min%"
   set "Sec=%Sec%"
)
exit /b