Dates in NT Batch Files.

The easy part is getting the date and time but doing it reliably takes a bit more. Simon Sheppard nails it:

@echo off&SETLOCAL
:: This will return date into environment vars
:: Works on any NT/2K/XP machine independent of regional date settings
:: 20 March 2002

FOR /f "tokens=1-4 delims=/-. " %%G IN ('date /t') DO (call :s_fixdate %%G %%H %%I %%J)
goto :s_print_the_date
   
:s_fixdate
if "%1:~0,1%" GTR "9" shift
FOR /f "skip=1 tokens=2-4 delims=(-)" %%G IN ('echo.^|date') DO (
   set %%G=%1&set %%H=%2&set %%I=%3)
goto :eof

:s_print_the_date
echo Month:[%mm%]  Day:[%dd%]  Year:[%yy%]
ENDLOCAL&SET mm=%mm%&SET dd=%dd%&SET yy=%yy%

:: see also http://www.robvanderwoude.com/amb_datetime.html
:: http://www.robvanderwoude.com/datetiment.html
:: http://www.commandline.co.uk/cmdfuncs/dandt/index.html

@echo off
SETLOCAL
   
:: This will return time into environment vars
:: Works on any NT/2K/XP machine independent of time format
:: 10 Nov 2002

FOR /f "tokens=*" %%G IN ('time/t') DO set v_time=%%G
SET v_time=%v_time:~0,2%-%v_time:~3,2%
ENDLOCAL&SET v_time=%v_time%
SET v

:: see also http://www.robvanderwoude.com/amb_datetime.html
:: http://www.commandline.co.uk/cmdfuncs/dandt/index.html

This incredible batch file, by Simon Sheppard completes the list of things you didn't think you could do in a batch file.

@ECHO off
SETLOCAL
:: DateMath, a general purpose date math routine

:: If DateMath detects an error, variable v_dd_int is set to 999999.
SET v_dd_int=0
SET v_mm_int=0 
SET v_yy_int=0
SET v_ymd_str=
SET v_mm_str=
SET v_dd_str=

IF "%3"=="" goto s_syntax
IF "%4"=="+" goto s_validate_year
IF "%4"=="-" goto s_validate_year
IF "%4"=="" goto s_validate_year

:s_syntax
echo.
echo DATEMATH SYNTAX:
echo _______________
echo.
echo DateMath will set the variables as listed below
echo 'str' variables include leading zeros e.g. "01"
echo 'int' variables leading zeros are stripped e.g. "1"
echo.
echo CALL DateMath YY MM DD - YY2 MM2 DD2 
echo.
echo Will set variable v_dd_int to the signed difference
echo between the 2 dates (measured in days)
echo.
echo.
echo CALL DateMath YY MM DD +/- Days 
echo.
echo Will set the following variables to the result of 
echo adding or substracting days from the initial date:
echo v_ymd_str, v_yy_int
echo v_mm_str, v_mm_int,
echo v_dd_str, v_dd_int
echo.
echo.
echo ___________________________________
pause
echo.
echo.
echo CALL DateMath YY MM DD
echo.
echo Will set the following variables:
echo v_ymd_str, v_yy_int
echo v_mm_str, v_mm_int,
echo v_dd_str, v_dd_int
echo.
echo ___________________________________
echo.
echo v_ymd_str is in YYYYMMDD format.
echo.
echo v_yy_int is in YYYY format, even if YY format was originally supplied.
echo This conversion is useful for FAT/NTFS file dates which are in YY format.
echo.
SET /a v_dd_int=999999
goto :eof
:s_validate_year
::strip leading zeros
SET v_yy=%1
if %v_yy:~0,1% EQU 0 set v_yy=%v_yy:~1%
:: Check for Y2K
IF %v_yy% LSS 100 IF %v_yy% GEQ 80 SET /A v_yy += 1900
IF %v_yy% LSS 80 SET /A v_yy += 2000

:: at this point v_yy contains a 4 digit year
::validate month and day
if %2 GTR 12 goto s_syntax
if %3 GTR 31 goto s_syntax
SET v_mm=%2
SET v_dd=%3
::strip leading zeros
if %v_mm:~0,1% EQU 0 set v_mm=%v_mm:~1%
if %v_dd:~0,1% EQU 0 set v_dd=%v_dd:~1%
:: Set the int variables
SET /a v_dd_int=%v_dd%
SET /a v_yy_int=%v_yy%
SET /a v_mm_int=%v_mm%
:: Determine which function to perform - ADD, SUBTRACT or CONVERT
If not "%6"=="" goto s_validate_2nd_date 
if "%4"=="" goto s_convert_only
:: Add or subtract days to a date
SET /a v_number_of_days=%5
goto s_add_or_subtract_days
:s_convert_only
SET /a v_dd_int=%v_dd%
IF %v_dd% LEQ 9 (SET v_dd_str=0%v_dd%) ELSE (SET v_dd_str=%v_dd%)
IF %v_mm% LEQ 9 (SET v_mm_str=0%v_mm%) ELSE (SET v_mm_str=%v_mm%)
SET v_ymd_str=%v_yy%%v_mm_str%%v_dd_str%
ECHO DATEMATH - Convert date only (no maths)
goto s_end
::::::::::::::::::::::::::::::::::::::::::::::::::

:s_validate_2nd_date
If "%4"=="+" goto s_syntax
:: Subtracting one date from another ::::::
:: strip leading zero
SET v_yy2=%5
if %v_yy2:~0,1% EQU 0 set v_yy2=%v_yy2:~1%
if %v_yy2% GTR 99 goto s_validate2nd_month
if %v_yy2% GTR 49 goto s_prefix_2_1950_1999
if %v_yy2% LSS 10 goto s_prefix_2_2000_2009
SET v_yy2=20%v_yy2%
goto s_validate2nd_month
:s_prefix_2_2000_2009
SET v_yy2=200%v_yy2%
goto s_validate2nd_month
:s_prefix_2_1950_1999
SET v_yy2=19%v_yy2%
:s_validate2nd_month
::strip leading zeros
::SET /a v_yy2=%v_yy2%
if %v_yy2:~0,1% EQU 0 set v_yy2=%v_yy2:~1%
::v_yy2 now contains a 4 digit year
if %6 GTR 12 goto s_syntax
SET v_mm2=%6
if %7 GTR 31 goto s_syntax
SET v_dd2=%7
::strip leading zeros
::SET /a v_mm2=%v_mm2%
if %v_mm2:~0,1% EQU 0 set v_mm2=%v_mm2:~1%
::SET /a v_dd2=%v_dd2%
if %v_dd2:~0,1% EQU 0 set v_dd2=%v_dd2:~1%
call :s_julian_day %v_yy_int% %v_mm_int% %v_dd_int%
SET v_sumdays1=%v_JulianDay%
call :s_julian_day %v_yy2% %v_mm2% %v_dd2%
SET v_sumdays2=%v_JulianDay%

SET /a v_dd_int=%v_sumdays1% - %v_sumdays2%

ECHO DATEMATH - Subtracting one date from another = days difference
ECHO ~~~~~~
ECHO %v_dd_int%
ECHO ~~~~~~
goto s_end_days
::::::::::::::::::::::::::::::::::::::::::::::::::

:s_add_or_subtract_days
if /i "%4"=="+" goto s_add_up_days
:: Subtract all days ::::::
SET /a v_dd=%v_dd% - %v_number_of_days%

:s_adjust_month_year
if %v_dd% GEQ 1 goto s_add_subtract_days_DONE
SET /a v_mm=%v_mm% - 1
if %v_mm% GEQ 1 goto s_add_days_%v_mm%
SET /a v_yy=%v_yy% - 1
SET /a v_mm=%v_mm% + 12
goto s_add_days_%v_mm%

:s_add_days_2
SET /a v_dd=%v_dd% + 28
SET /a v_leapyear=%v_yy% / 4
SET /a v_leapyear=%v_leapyear% * 4
if %v_leapyear% NEQ %v_yy% goto s_adjust_month_year
SET /a v_dd=%v_dd% + 1
goto s_adjust_month_year

:s_add_days_4
:s_add_days_6
:s_add_days_9
:s_add_days_11
SET /a v_dd=%v_dd% + 30
goto s_adjust_month_year
:s_add_days_1
:s_add_days_3
:s_add_days_5
:s_add_days_7
:s_add_days_8
:s_add_days_10
:s_add_days_12
SET /a v_dd=%v_dd% + 31
goto s_adjust_month_year

:s_add_up_days
:: add all days ::::::
SET /a v_dd=%v_dd% + %v_number_of_days%

:s_subtract_days_
goto s_subtract_days_%v_mm%

:s_adjust_mth_yr
SET /a v_mm=%v_mm% + 1
if %v_mm% LEQ 12 goto s_subtract_days_%v_mm%
SET /a v_yy=%v_yy% + 1
SET /a v_mm=%v_mm% - 12
goto s_subtract_days_%v_mm%
:s_subtract_days_2
SET /a v_leapyear=%v_yy% / 4
SET /a v_leapyear=%v_leapyear% * 4
If %v_leapyear% EQU %v_yy% goto s_subtract_leapyear
if %v_dd% LEQ 28 goto s_add_subtract_days_DONE
SET /a v_dd=%v_dd% - 28
goto s_adjust_mth_yr

:s_subtract_leapyear
if %v_dd% LEQ 29 goto s_add_subtract_days_DONE
SET /a v_dd=%v_dd% - 29
goto s_adjust_mth_yr

:s_subtract_days_4
:s_subtract_days_6
:s_subtract_days_9
:s_subtract_days_11
if %v_dd% LEQ 30 goto s_add_subtract_days_DONE
SET /a v_dd=%v_dd% - 30
goto s_adjust_mth_yr
:s_subtract_days_1
:s_subtract_days_3
:s_subtract_days_5
:s_subtract_days_7
:s_subtract_days_8
:s_subtract_days_10
:s_subtract_days_12
if %v_dd% LEQ 31 goto s_add_subtract_days_DONE
SET /a v_dd=%v_dd% - 31
goto s_adjust_mth_yr

:s_add_subtract_days_DONE
SET /a v_dd_int=%v_dd%
SET /a v_mm_int=%v_mm%
SET /a v_yy_int=%v_yy%
IF %v_dd% GTR 9 (SET v_dd_str=%v_dd%) ELSE (SET v_dd_str=0%v_dd%)
IF %v_mm% GTR 9 (SET v_mm_str=%v_mm%) ELSE (SET v_mm_str=0%v_mm%)
SET v_ymd_str=%v_yy%%v_mm_str%%v_dd_str%

ECHO DATEMATH - add or subtract days from a date = new date
goto s_end
::::::::::::::::::::::::::::::::::::::::::::::::::
:s_julian_day
SET v_year=%1
SET v_month=%2
SET v_day=%3

SET /a v_month=v_month
SET /a v_day=v_day

SET /A a = 14 - v_month
SET /A a /= 12
SET /A y = v_year + 4800 - a
SET /A m = v_month + 12 * a - 3
SET /A m = 153 * m + 2
SET /A m /= 5
SET /A v_JulianDay = v_day + m + 365 * y + y / 4 - y / 100 + y / 400 - 32045

ECHO The Julian Day is [%v_JulianDay%]
goto :eof
::::::::::::::::::::::::::::::::::::::::::::::::::

:s_end
ECHO ~~~~~~~~~~~~
ECHO [%v_ymd_str%] YY=[%v_yy_int%] MM=[%v_mm_str%] DD=[%v_dd_str%]
ECHO ~~~~~~~~~~~~
:s_end_days
ENDLOCAL&SET /a v_yy_int=%v_yy_int%&SET /a v_mm_int=%v_mm_int%&SET /a v_dd_int=%v_dd_int%&SET v_ymd_str=%v_ymd_str%&SET v_mm_str=%v_mm_str%&SET v_dd_str=%v_dd_str%
 


D:\>datemath 02 05 08
DATEMATH - Convert date only (no maths)
~~~~~~~~~~~~
[20020508] YY=[2002] MM=[05] DD=[08]
~~~~~~~~~~~~
 
D:\>datemath 2007 12 30
DATEMATH - Convert date only (no maths)
~~~~~~~~~~~~
[20071230] YY=[2007] MM=[12] DD=[30]
~~~~~~~~~~~~
 
 
D:\>datemath 27 12 01 - 02 11 02
The Julian Day is [2461741]
The Julian Day is [2452581]
DATEMATH - Subtracting one date from another = days difference
~~~~~~
9160
~~~~~~
 
D:\>datemath 02 11 02 + 9160
DATEMATH - add or subtract days from a date = new date
~~~~~~~~~~~~
[20271201] YY=[2027] MM=[12] DD=[01]
~~~~~~~~~~~~
 
D:\>datemath 12 09 08 - 11 09 08
The Julian Day is [2456179]
The Julian Day is [2455813]
DATEMATH - Subtracting one date from another = days difference
~~~~~~
366
~~~~~~
 
D:\>datemath 13 09 08 - 12 09 08
The Julian Day is [2456544]
The Julian Day is [2456179]
DATEMATH - Subtracting one date from another = days difference
~~~~~~
365
~~~~~~
 

And now, we can do someting with it.

@echo off&SETLOCAL

::  DELOLDER.cmd days fullpath
::
::  For example:  
::      DELOLDER 14 C:\temp\*.*
::      DELOLDER 28 "C:\Log Files\"
::      DELOLDER 28 "C:\Log Files\*.LOG"

:: note: do not specify the Current Directory

:: To use this batch for real, edit the last line below
:: i.e. change [ECHO DELETE the file] to [DEL] or [MOVE] or whatever

SET v_days_newer=%1
SET v_source=%2

:: get todays date from getdate.cmd
CALL GetDate
SET yy=%yy:~2,2%

:: calculate new date using DateMath.cmd
CALL DateMath %yy% %mm% %dd% - %v_days_newer%

ECHO Files older than Year: [%v_yy_int%] Month: [%v_mm_str%] Day: [%v_dd_str%]

:: Compare each file in the DIR with files that are newer than day X
:: and delete all those that don't match (ie are older)

FOR /f "tokens=*" %%G IN ('XCOPY %v_source% /L ^| FIND "\"') DO CALL :s_match_older "%%G"
goto :eof

:s_match_older
FOR /f "tokens=*" %%G IN ('XCOPY %v_source% /D:%v_mm_str%-%v_dd_str%-%v_yy_int% /L ^| FIND "\"') DO IF %1=="%%G" (GOTO :eof)
ECHO DELETE the file %1

Questions:

• vinexas at spamgmail.com asks: " Hi
  I dont understand this line in :s_fixdate
  if "%1:~0,1%" GTR "9" shift
  Why gtr 9? What is the clue?
  
  Pepo" James Newton of MassMind replies: That is skipping past non-numeric parts of the date.+

  +