delefile.bat

dos备份时

:: 演示删除当前前numday天，以日期为命名的文件
:: wulb - 2008-4-9 
@echo off
set numday=-2
echo 准备开始删除%date%前%numday%天的文件
set olddate=%date:~0,10%
call :Date2Day %olddate% days
set/a days=%days%+numday
call :Day2Date %days% deldate
echo -----------开始删除旧文件---------
echo 删除%deldate%日期以前的文件,不包括%deldate%的文件

for %%f in (*.txt) do call :deloldfile %%f %deldate%

cmd /k
echo -----------删除结束---------

:Date2Day
setlocal ENABLEEXTENSIONS 
for /f "tokens=1-3 delims=/-, " %%a in ('echo/%1') do ( 
  set yy=%%a & set mm=%%b & set dd=%%c 
)
set /a dd=100%dd%%%100,mm=100%mm%%%100 
set /a z=14-mm,z/=12,y=yy+4800-z,m=mm+12*z-3,j=153*m+2 
set /a j=j/5+dd+y*365+y/4-y/100+y/400-2472633
endlocal&set %2=%j%&goto :EOF 

:Day2Date
setlocal ENABLEEXTENSIONS 
set /a i=%1,a=i+2472632,b=4*a+3,b/=146097,c=-b*146097,c/=4,c+=a 
set /a d=4*c+3,d/=1461,e=-1461*d,e/=4,e+=c,m=5*e+2,m/=153,dd=153*m+2,dd/=5 
set /a dd=-dd+e+1,mm=-m/10,mm*=12,mm+=m+3,yy=b*100+d-4800+m/10 
(if %mm% LSS 10 set mm=0%mm%)&(if %dd% LSS 10 set dd=0%dd%) 
endlocal&set %2=%yy%-%mm%-%dd%&goto :EOF 

:deloldfile
set filename=%1
set dates=%2
echo %filename%
set  filedate=%filename:~-14,10%
if %filedate% LSS %dates% del  %filename%
goto :EOF