我希望这次运行并显示上个月。当我尝试减去月份时，它会显示月份的最后一天字段。
@echo off
set FirstDay=01
set Month=%date:~4,2%
set Year=%date:~10,4%
if %Month%==01 set LastDay=31 & goto foundate
if %Month%==02 set LastDay=28 & goto foundate
if %Month%==03 set LastDay=31 & goto foundate
if %Month%==04 set LastDay=30 & goto foundate
if %Month%==05 set LastDay=31 & goto foundate
if %Month%==06 set LastDay=30 & goto foundate
if %Month%==07 set LastDay=31 & goto foundate
if %Month%==08 set LastDay=31 & goto foundate
if %Month%==09 set LastDay=30 & goto foundate
if %Month%==10 set LastDay=31 & goto foundate
if %Month%==11 set LastDay=30 & goto foundate
if %Month%==12 set LastDay=31 & goto foundate
:foundate
echo The year is: %Year%
echo The month is: %Month%
echo First day of this month is: %FirstDay%
echo Last day of this month is: %LastDay%
答案 0 :(得分：0)
这是上个月会得到的一段代码：
@echo off
for /f "" %%# in ('WMIC Path Win32_LocalTime Get month /format:value') do (
for /f %%Z in ("%%#") do set /a %%Z-1
)
if %month% equ 0 set month=12
echo %month%
更好地使用wmic来获取日期部分，因为它与机器的日期格式无关，与%date%变量不同。
编辑（根据评论中的要求）：
@echo off
setlocal disableDelayedExpansion
for /f "" %%# in ('"WMIC Path Win32_LocalTime Get month,year /format:value"') do (
for /f %%Z in ("%%#") do set "%%Z"
)
set /a month=month-1
if %month% equ 0 set month=12
rem echo %month% -- %year%
set /A "leap=!(year&3) + (!!(year%%100)-!!(year&15))"
if %leap% equ 0 (set "m2=29") else (set "m2=28")
setlocal enableDelayedExpansion
set m1=31
set m3=31
set m4=30
set m5=31
set m6=30
set m7=31
set m8=31
set m9=30
set m10=31
set m11=30
set m12=31
set premonLastDay=!m%month%!
endlocal & set premonLastDay=%premonLastDay%
if %month% equ 12 (
set /a year=year-1
)
echo %premonLastDay%-%month%-%year%
endlocal
答案 1 :(得分：0)
我创建了一个具有这些功能的函数库。您可以使用此库轻松完成所需操作，请查看以下内容。
这些功能位于代码的末尾。只需复制到文件的末尾（在goto：eof之后）并使用指定的参数调用它们。
里面给出的代码：main应该做你想要的。
<强>说明：
<强>代码：
@echo off
:main
:: Recommended to use GetDateIntl function, to get region-independent results (Check functions at the end of this file)
call :GetDateIntl Year Month Day /A
echo/Using GetDateIntl to get current date: %Year%-%Month%-%day%
echo/
:: Call function to get last day of this month (Check functions at the end of this file)
call :GetLastDayOfMonth %Month% %Year% LastDay
echo This month is: %Month%/%Year%
echo First day of any month is always 1
echo Last day of this month is: %LastDay%
echo/
:: Get previous month number
set /A "PMonth= %Month% - 1"
set "PYear=%Year%"
:: Correct PMonth and PYear if this month is December
if %PMonth%==0 ( set "PMonth=12" & set /A "PYear= %PYear% - 1" )
:: Call function to get last day of previous month (Check function after :main)
call :GetLastDayOfMonth %PMonth% %PYear% PLastDay
echo Previous month is: %PMonth%/%PYear%
echo Last day of previous month is: %PLastDay%
goto:eof
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
:GetDateIntl yy mm dd [/A]
:: Returns the current date on any machine with regional-independent settings
:: Arguments:
:: yy = variable name for the year output
:: mm = variable name for the month output
:: dd = variable name for the day output
:: /A = OPTIONAL, removes leading 0 on days/months smaller than 10
::
:: By Cyberponk, v1.1 - 11/05/2016
:: v1.0 - 2015
::
SETLOCAL ENABLEEXTENSIONS
if "%date%A" LSS "A" (set toks=1-3) else (set toks=2-4)
for /f "tokens=2-4 delims=(-)" %%a in ('echo:^|date') do (
for /f "tokens=%toks% delims=.-/ " %%i in ('date/t') do (
set '%%a'=%%i
set '%%b'=%%j
set '%%c'=%%k
)
)
if "%'yy'%"=="" set 'yy'=%'aa'%
if %'yy'% LSS 100 set 'yy'=20%'yy'%
endlocal&set %1=%'yy'%&set %4 %2=%'mm'%&set %4 %3=%'dd'%&goto :EOF
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
:IsLeapYear %year% IsLeap
:: Checks if a year is a Leap Year (year that has 366 days)
:: Arguments:
:: %year% = year number input. Can be a number or a variable containing a 4 digit number
:: IsLeap = result output containing 1 or 0 (1= is leap year, 0= not yeap lear)
::
:: By Cyberponk, v1.1 - 11/05/2016
::
SETLOCAL ENABLEEXTENSIONS
set /A "IsLeap=(!(%1 %% 4) & !!(%1 %% 100)) | !(%1 %% 400)"
endlocal & set %2=%IsLeap%& goto:EOF
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
:GetLastDayOfMonth %month% %year% LastDay
:: Gets the last day of a given month from a given year
:: Arguments:
:: %month% = month number input. Can be a number or a variable containing a number
:: %year% = year for reference (used to check for leap years)
:: LastDay = result output containing last day of the specified month
::
:: By Cyberponk, v1.0 - 11/05/2016
::
SETLOCAL ENABLEEXTENSIONS
:: Mathematical formula to last day of month
set /A "LastDay= 28 + (%1 + (%1/8)) %% 2 + 2 %% %1 + 2 * (1/%1)
:: Add 1 day if year is a Leap Year and month is February
call :IsLeapYear %2 IsLeap
if %LastDay%==28 set /A LastDay=%LastDay% + %IsLeap%
endlocal & set %3=%LastDay%& goto:EOF
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
答案 2 :(得分：0)
日期很复杂，容易出错，如果你可以避免自己滚动，那就这样做。
CMD没有本机日期库，但.NET System.DateTime库可通过PowerShell获得。以下PS脚本显示了如何使用.NET来执行您所要求的操作。
$lastmonth = (Get-Date).addMonths(-1)
"The year is $($lastmonth.year)"
"The month is $($lastmonth.Month)"
"First day of this month is 01"
"Last day of this month is $([DateTime]::DaysInMonth($lastmonth.year, $lastmonth.month))"
几乎所有这个脚本都在格式化输出。要从CMD运行，请使用命令
启动它powershell.exe -ex bypass -f Get-LastMonthStats.ps1
或者，如果您不想创建单独的.ps1文件，则可以将整个脚本放在一个（非常长的）命令行上。
powershell -c "$lastmonth = (Get-Date).addMonths(-1); 'The year is ' + $lastmonth.year; 'The month is ' + $lastmonth.Month; 'First day of this month is 01'; 'Last day of this month is ' + [DateTime]::DaysInMonth($lastmonth.year, $lastmonth.month)"
答案 3 :(得分：0)
我已针对以下错误修改了Cyberponk脚本
上个月是：-1/2020
之后
if "%'yy'%"=="" set 'yy'=%'aa'%
我已添加为修复程序
if %'mm'% LSS 10 set 'mm'=%'mm':~1,1%