用bat脚本计算前一天时间

可以使用以下代码计算前一天的日期：

@echo off
setlocal enabledelayedexpansion

set "today=%date%"
set /a "day=1%today:~0,2%-100"
set /a "month=1%today:~3,2%-100"
set /a "year=today:~6,4%"
set /a "days=0"

if %month% equ 1 (
  set /a "days=31"
) else if %month% equ 2 (
  if %year% equ 0 (
    set /a "days=29"
  ) else if %year% mod 4 equ 0 (
    if %year% mod 100 neq 0 (
      set /a "days=29"
    ) else if %year% mod 400 eq 0 (
      set /a "days=29"
    ) else (
      set /a "days=28"
    )
  ) else (
    set /a "days=28"
  )
) else if %month% equ 3 (
  set /a "days=31"
) else if %month% equ 4 (
  set /a "days=30"
) else if %month% equ 5 (
  set /a "days=31"
) else if %month% equ 6 (
  set /a "days=30"
) else if %month% equ 7 (
  set /a "days=31"
) else if %month% equ 8 (
  set /a "days=31"
) else if %month% equ 9 (
  set /a "days=30"
) else if %month% equ 10 (
  set /a "days=31"
) else if %month% equ 11 (
  set /a "days=30"
) else if %month% equ 12 (
  set /a "days=31"
)

set /a "day=day-1"
if %day% equ 0 (
  set /a "month=month-1"
  if %month% equ 0 (
    set /a "year=year-1"
    set /a "month=12"
  )
  if %month% equ 2 (
    if %year% equ 0 (
      set /a "days=29"
    ) else if %year% mod 4 equ 0 (
      if %year% mod 100 neq 0 (
        set /a "days=29"
      ) else if %year% mod 400 eq 0 (
        set /a "days=29"
      ) else (
        set /a "days=28"
      )
    ) else (
      set /a "days=28"
    )
  )
  set /a "day=days"
)

set "month=0%month%"
set "day=0%day%"
set "year=000%year%"
set "month=!month:~-2!"
set "day=!day:~-2!"
set "year=!year:~-4!"

echo %year%%month%%day%

这个脚本会获取当前日期，然后计算前一天的日期，并将其输出。注意，这个脚本只能在 Windows 系统上运行。