批處理獲得系統當前時間之前n天的時間

@echo off
::獲得前一天的系統時間
::時間處理部分來自網際網路。
SetLocal EnableDelayedExpansion
::if "%1"=="" echo 示例: %0 20080102 5 && pause>nul && exit /B
set dd=%DATE:~8,2%
set mm=%DATE:~5,2%
set yyyy=%DATE:~0,4%
set temp1=%yyyy%%mm%%dd%
::set temp1=20090527
set temp2=1
set YE=%temp1:~0,4%
set MO=%temp1:~4,2%
set DA=%temp1:~6,2%
set DG=%temp2%
for %%i in (YE MO DA DG) do if "!%%i!"=="" echo Caution,Error Format & pause>nul & exit/b
for %%j in (YE MO DA DG) do if !%%j! LEQ 0 echo Caution,Error Format & pause>nul & exit/b
set/a vY1=%YE% %% 400
set/a vY2=%YE% %% 4
set/a vY3=%YE% %% 100
if %vY1%==0 (set var=true) else (
if %vY2%==0 (
if %vY3%==0 (set var=false) else (set var=true)
) else (set var=false )
)
if %DG% GEQ 28 echo Error,Not Support Large Days! & pause>nul & exit /B
set LY=%YE%
set LM=%MO%
if %var%==false (
if %MO%==01 (if %DA% LEQ %DG% (set/a LY=%YE%-1) & (set/a LM=12+%MO%-1) & (set/a LD=31+%DA%-%DG%) else (set/a LD=%DA%-%DG%))
if %MO%==03 (if %DA% LEQ %DG% (set/a LM=%MO%-1) & (set/a LD=28+%DA%-%DG%) else (set/a LD=%DA%-%DG%))
for %%a in (02 04 06 11) do (if "%MO%"=="%%a" (if %DA% LEQ %DG% (set/a LM=%MO%-1) & (set/a LD=31+%DA%-%DG%) else (set/a LD=%DA%-%DG%)))
if %MO%==09 (if %DA% LEQ %DG% (set/a LM=8) & (set/a LD=31+%DA%-%DG%) else (set/a LD=%DA%-%DG%))
for %%b in (05 07 10 12) do (if "%MO%"=="%%b" (if %DA% LEQ %DG% (set/a LM=%MO%-1) & (set/a LD=30+%DA%-%DG%) else (set/a LD=%DA%-%DG%)))
if %MO%==08 (if %DA% LEQ %DG% (set/a LM=7) & (set/a LD=30+%DA%-%DG%) else (set/a LD=%DA%-%DG%))
) else (
if %MO%==01 (if %DA% LEQ %DG% (set/a LY=%YE%-1) & (set/a LM=12+%MO%-1) & (set/a LD=31+%DA%-%DG%) else (set/a LD=%DA%-%DG%))
if %MO%==03 (if %DA% LEQ %DG% (set/a LM=%MO%-1) & (set/a LD=29+%DA%-%DG%) else (set/a LD=%DA%-%DG%))
for %%a in (02 04 06 11) do (if "%MO%"=="%%a" (if %DA% LEQ %DG% (set/a LM=%MO%-1) & (set/a LD=31+%DA%-%DG%) else (set/a LD=%DA%-%DG%)))
if %MO%==09 (if %DA% LEQ %DG% (set/a LM=8) & (set/a LD=31+%DA%-%DG%) else (set/a LD=%DA%-%DG%))
for %%b in (05 07 10 12) do (if "%MO%"=="%%b" (if %DA% LEQ %DG% (set/a LM=%MO%-1) & (set/a LD=30+%DA%-%DG%) else (set/a LD=%DA%-%DG%)))
if %MO%==08 (if %DA% LEQ %DG% (set/a LM=7) & (set/a LD=30+%DA%-%DG%) else (set/a LD=%DA%-%DG%))
)
if %LM% LSS 10 set LM=0%LM:~-1%
if %LD% LSS 10 set LD=0%LD:~-1%
echo %LY%%LM%%LD%
for %%a in (01 02 03 04 05 06 07 08 09) do (
if "%LM%"=="%%a" (
set m= %LM:~1,1%)
)
for %%b in (10 11 12) do (
if "%LM%"=="%%b" (
set m= %LM%)
)
set LM_NEW=%m:~1,2%
echo %LY%%LM_NEW%%LD%

用於日誌處理。

對原有的程式碼進行修改，主要是月份為8月和9月時，計算上一個月時使用set /a=09-1時，會報錯：

“無效數字。數字常數只能是十進位制(17)，十六位進位制(0x11)或
八進位制(021)。”

[@more@]