@echo off & setlocal enabledelayedexpansion
set "y=%date:~0,4%" & set "m=%date:~5,2%" & set /a "m=1!m!-101, m=m+(^!m)*12"
set /a "f=^!(m-2), s=^!(m-4)|^!(m-6)|^!(m-9)|^!(m-11)" & rem 上月是否2月或小月
set /a "leap=^!(y%%4) & ^!^!(y%%100) | ^!(y%%400)" & rem 今年是否闰年
set /a "d=f*(28+leap)+s*30+(^!f&^!s)*31" & rem 上月有 !d! 天
set /a "y1=y-^!(m-12)"
set "m=0!m!" & set "m=!m:~-2!" & set "d=0!d!" & set "d=!d:~-2!"
echo 上个月月末的日期是 !y1!-!m!-!d!
pause
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@echo off
rem 调用GNU for Win32的date.exe
set "gnuDate=C:\test\date.exe"
for /f %%a in ('%gnuDate% "+%%Y%%m01"') do (
    for /f %%h in ('%gnuDate% -d "%%a 1 days ago" "+%%Y-%%m-%%d"') do (
        set "lastEndDay=%%h"
    )
)
echo,%lastEndDay%
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WScript.echo DateAdd("d", -DatePart("d", Date), date)
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@echo off
>"%temp%\DstDate.vbs" echo strLastDate=DateAdd("d", -DatePart("d", Date), Date)
>>"%temp%\DstDate.vbs" echo strFmtDate=Right(Year(strLastDate),4) ^& Right("0" ^& Month(strLastDate),2) ^& Right("0" ^& Day(strLastDate),2)
>>"%temp%\DstDate.vbs" echo WScript.Echo strFmtDate
for /f %%a in ('cscript /nologo "%temp%\DstDate.vbs"') do (
    set "lastEndDay=%%a"
)
set lastEndDay=%lastEndDay:~0,4%-%lastEndDay:~4,2%-%lastEndDay:~6,2%
echo,%lastEndDay%
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@echo off
rem 调用Bill Stewart的DateX.exe
set "xDate=C:\test\DateX.exe"
rem 假设系统日期格式是yyyy-mm-dd
set day=%date:~8,2%
for /f %%a in ('"%xDate%" -o -%day%') do (
    set "lastEndDay=%%a"
)
echo,%lastEndDay%
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@echo off
set /a "m=1%date:~5,2%-101",y=%date:~,4%-!m","m+=!m*12,"d=30+(m-m/8)%%2-!(m-2)*2-!(m-2)*(!(y%%4)&!(!(y%%100))|!(y%%400))"
echo %m%月%d%日
pause
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