vbs实现只复制比目标文件更新的文件

@echo off
::每5分钟复制以下首页
for /f %%i in ('dir /b c:\index2.htm') do (
set indexdx=%%~zi
)
if %indexdx% gtr 5120 (
echo y | xcopy c:\index2.htm /d /r /k c:\index.htm
)

Dim fso
Set fso = CreateObject("Scripting.FileSystemObject")
set fn2=fso.GetFile("c:\index2.htm")
flsize2=fn2.size
fldate2=fn2.datelastmodified
set fn=fso.GetFile("c:\index.htm")
flsize1=fn.size
fldate1=fn.datelastmodified
If fso.FileExists("c:\index2.htm") and flsize2>50000 and fldate2>fldate1 Then
fso.getfile("c:\index2.htm").copy("c:\index.htm")
if err.number=0 then WriteHistory "成功"&now(),"log.txt"
end if

Sub WriteHistory(hisChars, path)
Const ForReading = 1, ForAppending = 8
Dim fso, f
Set fso = CreateObject("Scripting.FileSystemObject")
Set f = fso.OpenTextFile(path, ForAppending, True)
f.WriteLine hisChars
f.Close
End Sub