for /F "tokens=2,3,4 delims=- " %%i in ("%date%") do rar a %%k%%j%%i.rar ...
или
for /F "tokens=2,3,4 delims=- " %%i in ('date /t') do rar a %%k%%j%%i.rar ...

rar a %date:~9,4%%date:~6,2%%date:~3,2%.rar ...
или
rar a %date:~-4%%date:~-7,2%%date:~-10,2%.rar ...
или
rar a %date:~-4,4%%date:~-7,-5%%date:~-10,-8%.rar ...

for /F "eol=; tokens=1,2 delims= " %%i in (rules.txt) do move /Y %%i %%j

for /F "tokens=* " %%i in ('calcdate.bat "dd DD.MM.YYYY" "%date%" -183') do set $date=%%i
set year=%$date:~0,4%
set month=%$date:~4,2%
set day=%$date:~-2%
rem Результат
echo YYYY=%year%; MM=%month%; DD=%day%

@echo off
rem ---------- calcdate.bat ----------
rem --- Written by Den[bugtraq.ru] ---
rem ----------------------------------
rem Enter: %1 - Формат передающейся даты в двойных кавычках: DD, MM, YYYY в любой последовательности с любыми разделителями. Пример: "dd DD-MM-YYYY", dd используются для пропускания дней недели.
rem %2 - Дата в двойных кавычках указанного в %1 формата
rem %3 - Дельта со знаком. Примеры: -180, +3
rem Exit: В стандартном выходе расчетная дата формата YYYYMMDD
setlocal
set $date=%~2
call :getpos YYYY "%~1"
if defined $pos (call set year=%%$date:~%$pos%,4%%) else goto :EOF
call :getpos MM "%~1"
if defined $pos (call set month=%%$date:~%$pos%,2%%) else goto :EOF
call :getpos DD "%~1"
if defined $pos (call set day=%%$date:~%$pos%,2%%) else goto :EOF
rem Отбрасываем признак восьмеричного числа.
for /F "tokens=* delims=0" %%i in ("%day%") do set /a daycount=%%i
for /F "tokens=* delims=0" %%i in ("%year%") do set /a year=%%i
for /F "tokens=* delims=0" %%i in ("%month%") do set /a month=%%i
rem Кол-во високосных
set /a i=(%year%-1)/4
rem Текущий после високосного, если j==4, то идет високосный
set /a j=%year%-%i%*4
rem Кол-во дней в полных годах до текущего
set /a daycount+=%i%*1461+(%j%-1)*365
set /a i=%month%

:loop
set /a i-=1
if %i%==0 goto :next
if %i%==1 set /a daycount+=31
if %i%==2 (if %j%==4 (set /a daycount+=29) else set /a daycount+=28)
if %i%==3 set /a daycount+=31
if %i%==4 set /a daycount+=30
if %i%==5 set /a daycount+=31
if %i%==6 set /a daycount+=30
if %i%==7 set /a daycount+=31
if %i%==8 set /a daycount+=31
if %i%==9 set /a daycount+=30
if %i%==10 set /a daycount+=31
if %i%==11 set /a daycount+=30
if %i%==12 set /a daycount+=31
goto :loop

:next
rem Days after christmas: %daycount%
set /a daycount+=%3
rem Result=%daycount%
set /a i=%daycount%/1461
set /a j=%daycount%-%i%*1461
if %j%==0 set /a i-=1
set /a daycount-=%i%*1461
set /a year=%i%*4
set /a i=%daycount%/365
if %j%==0 set /a i-=1
set /a j=%daycount%-%i%*365
if %j%==0 set /a i-=1
set /a daycount-=i*365
set /a i+=1
set /a year+=%i%
set /a j=%daycount%
set /a month=1

:loop_1
if %month%==1 set /a j-=31
if %month%==2 (if %i%==4 (set /a j-=29) else set /a j-=28)
if %month%==3 set /a j-=31
if %month%==4 set /a j-=30
if %month%==5 set /a j-=31
if %month%==6 set /a j-=30
if %month%==7 set /a j-=31
if %month%==8 set /a j-=31
if %month%==9 set /a j-=30
if %month%==10 set /a j-=31
if %month%==11 set /a j-=30
if %month%==12 set /a j-=31
if %j% LEQ 0 goto :next_1
set /a month+=1
set /a daycount=%j%
goto :loop_1

:next_1
set lz=0000
call :getlen "%year%"
set /a $len=4-%$len%
if not %$len%==0 call set year=%%lz:~-%$len%%%%year%
call :getlen "%month%"
set /a $len=2-%$len%
if not %$len%==0 call set month=%%lz:~-%$len%%%%month%
set /a days=%daycount%
call :getlen "%days%"
set /a $len=2-%$len%
if not %$len%==0 call call set days=%%lz:~-%$len%%%%days%
echo %year%%month%%days%
endlocal
goto :EOF


:getlen
rem Enter: %1 - Строка в двойных кавычках
rem Exit: $len - Длина строки без учета двойных кавычек
set par=%~1
set /a i=0
set $len=

:getlen_loop
call :getlen_1 "%%par:~%i%,1%%"
if defined $len goto :EOF
set /a i+=1
goto :getlen_loop

:getlen_1
if %1=="" set /a $len=%i%
goto :EOF

:getpos
rem Enter: %1 - Искомая строка в двойных кавычках
rem %2 - Строка-источник в двойных кавычках
rem Exit: $pos - Позиция искомой строки в строке-источнике без учета двойных кавычек.
call :getlen "%~1"
set /a $findlen=%$len%

call :getlen "%~2"
set /a $formatlen=%$len%-1
set par=%~2
set /a i=0
set $pos=

:getpos_loop
call :getpos_1 %i% "%~1" "%%par:~%i%,%$findlen%%%"
if defined $pos goto :EOF
if %i%==%$formatlen% goto :EOF
set /a i+=1
goto :getpos_loop

:getpos_1
if %2==%3 set /a $pos=%i%
goto :EOF
rem ---------- END calcdate.bat ----------

@echo off
rem ---------- deltabkp.cmd ----------
rem --- Written by Den[bugtraq.ru] ---
rem ----------------------------------
rem Enter: %1 - Source directory
rem   %2 - Date delta
setlocal
if "%~2"=="" (
  echo !Error! Date delta not defined.
  goto :eof
)
set /a datedelta=%~2
if "%~1"=="" (
  echo !Error! File directory not defined.
  goto :eof
)
set srcdir=%~f1
if "%srcdir:~-1,1%"=="\" set srcdir=%srcdir:~0,-1%
rem --- Получаем разделитель и формат даты
:loopreg
set regfile=%random%.reg
if exist %regfile% goto :loopreg
regedit /e %regfile% "HKEY_CURRENT_USER\Control Panel\International"
if not exist %regfile% (
  echo !Error! REG file not found.
  goto :eof
)
for /F "skip=2 tokens=1,* delims== eol=[" %%i in ('type %regfile%') do if "sDate"=="%%~i" (
  set datedelim=%%~j
) else if "sShortDate"=="%%~i" set dateform= %%~j
del /Q %regfile%
if not defined datedelim (
  echo !Error! Date delimiter not defined.
  goto :eof
) else if not defined dateform (
  echo !Error! Date format not defined.
  goto :eof
)
set dateform=%dateform:d=D%
set dateform=%dateform:m=M%
for /F "delims=yY tokens=1,*" %%k in ("%dateform%") do set dateform=%%kYYYY%%l
set dateform=%dateform:~1%

rem --- Получаем позиции DD,MM,YYYY
for /F "delims=%datedelim% tokens=1,2,3" %%i in ("%dateform%") do (
  if "%%i"=="DD" (
    if "%%j"=="MM" (set $dateorder=%%z%%y%%%x
    ) else (set $dateorder=%%y%%z%%%x
  )) else if "%%i"=="MM" (
    if "%%j"=="DD" (set $dateorder=%%z%%x%%%y
    ) else (set $dateorder=%%y%%x%%%z
  )) else (
    if "%%j"=="DD" (set $dateorder=%%x%%z%%%y
    ) else (set $dateorder=%%x%%y%%%z
  ))
)
rem --- Получаем дату по дельте от текущей
for /F %%i in ('calcdate.cmd "dd %dateform%" "%date%" %datedelta%') do set $date=%%i
:looptmpfile
set tmpfile=%temp%\dbp%random%.tmp
if exist %tmpfile% goto :looptmpfile
set lvl=0
set baklvl=0
set $dir=
rem "File Not Found" error message from "dir "%~1\*" /a-d/4" command to NUL
call :nextlvl "%srcdir%" 2>nul
if exist %tmpfile% del /Q %tmpfile%
endlocal
goto :eof

:do
rem ----- START BACKUP -----
rem Examples
rem call backup.cmd "%~1"
rem rar m -cfg- -ep2 -idp -m5 -os -ow -s -t -- old_%$date%.rar "%~1"
echo dir=%1
rem ------ END BACKUP ------
goto :eof

:nextlvl
set /a lvl+=1
set /a baklvl+=1
for /F %%d in ('dir /b /ad "%~1\*"') do (
  call :nextlvl "%~1\%%d"
)
if %baklvl% LSS %lvl% (
rem --- New files in subdirectories
  set /a updlvl=%lvl%-1
  set /a lvl-=1
  goto :eof
)

set updated=0
dir "%~1\*" /a-d/4 >nul
if errorlevel 0 (
  for /F "skip=5 tokens=1 eol=  " %%f in ('dir "%~1\*" /a-d/4') do (
    for /F "tokens=1,2,3 delims=%datedelim%" %%x in ("%%f") do (
      if not "%%y"=="" (
        if %$dateorder% GTR %$date% set updated=-1
      )))
)

if %updated%==-1 (
rem --- New files found in directory
  if %baklvl% GTR %lvl% (
  rem --- Old files in subdirectories, back it up!
    for /F "tokens=*" %%f in (%tmpfile%) do call :do %%f
    del /Q %tmpfile%
  )
  set /a lvl-=1
  goto :eof
) else (
rem --- New Files not found in directory
  set baklvl-=1
  echo "%~1" >>%tmpfile%
)

:ret
set /a lvl-=1
goto :eof