29

我正在尝试通过目录递归并将其从 A 复制到 B。这可以通过以下方式完成：

Copy-Item C:\MyTest C:\MyTest2 –recurse

我希望能够只复制新文件（存在于 src 但不存在于 dest 中的文件），并且只复制可能基于 CRC 检查而不是日期时间戳而更改的文件。

$file = "c:\scripts"
param
(
$file
)

$algo = [System.Security.Cryptography.HashAlgorithm]::Create("MD5")
$stream = New-Object System.IO.FileStream($file, [System.IO.FileMode]::Open)

$md5StringBuilder = New-Object System.Text.StringBuilder
$algo.ComputeHash($stream) | `
% { [void] $md5StringBuilder.Append($_.ToString("x2")) }
$md5StringBuilder.ToString()

$stream.Dispose()

此代码为我提供了对特定文件的 CRC 检查...我只是不确定如何将两个脚本放在一起以真正满足我的需求。我也不知道上面的 CRC 检查是否真的是这样做的正确方法。

有没有人有任何见解？

4

4 回答 4

37

这两个都是 powershell 的可靠答案，但仅利用Robocopy（MS 提供的健壮复制应用程序）可能会容易得多。

robocopy "C:\SourceDir\" "C:\DestDir\" /MIR

会完成同样的事情。

于 2011-03-25T13:32:24.287 回答
10

以下是一些指导方针，您可以如何使您的脚本更易于维护。

将原始脚本转换为过滤器。

filter HasChanged { 
    param($file)

    # if $file's MD5 has does not exist
    # then return $_
}

然后只需过滤所有更新的文件并复制它们。

# Note that "Copy-Item" here does not preserve original directory structure
# Every updated file gets copied right under "C:\MyTest2"
ls C:\MyTest -Recurse | HasChanged | Copy-Item -Path {$_} C:\MyTest2

或者您可以创建另一个生成子目录的函数

ls C:\MyTest -Recurse | HasChanged | % { Copy-Item $_ GenerateSubDirectory(...) }
于 2009-03-24T16:18:46.597 回答
4

我找到了一个解决方案......但不确定从性能角度来看它是最好的：

$Source = "c:\scripts"
$Destination = "c:\test"
###################################################
###################################################
Param($Source,$Destination)
function Get-FileMD5 {
    Param([string]$file)
    $mode = [System.IO.FileMode]("open")
    $access = [System.IO.FileAccess]("Read")
    $md5 = New-Object System.Security.Cryptography.MD5CryptoServiceProvider
    $fs = New-Object System.IO.FileStream($file,$mode,$access)
    $Hash = $md5.ComputeHash($fs)
    $fs.Close()
    [string]$Hash = $Hash
    Return $Hash
}
function Copy-LatestFile{
    Param($File1,$File2,[switch]$whatif)
    $File1Date = get-Item $File1 | foreach-Object{$_.LastWriteTimeUTC}
    $File2Date = get-Item $File2 | foreach-Object{$_.LastWriteTimeUTC}
    if($File1Date -gt $File2Date)
    {
        Write-Host "$File1 is Newer... Copying..."
        if($whatif){Copy-Item -path $File1 -dest $File2 -force -whatif}
        else{Copy-Item -path $File1 -dest $File2 -force}
    }
    else
    {
        #Don't want to copy this in my case..but good to know
        #Write-Host "$File2 is Newer... Copying..."
        #if($whatif){Copy-Item -path $File2 -dest $File1 -force -whatif}
        #else{Copy-Item -path $File2 -dest $File1 -force}
    }
    Write-Host
}

# Getting Files/Folders from Source and Destination
$SrcEntries = Get-ChildItem $Source -Recurse
$DesEntries = Get-ChildItem $Destination -Recurse

# Parsing the folders and Files from Collections
$Srcfolders = $SrcEntries | Where-Object{$_.PSIsContainer}
$SrcFiles = $SrcEntries | Where-Object{!$_.PSIsContainer}
$Desfolders = $DesEntries | Where-Object{$_.PSIsContainer}
$DesFiles = $DesEntries | Where-Object{!$_.PSIsContainer}

# Checking for Folders that are in Source, but not in Destination
foreach($folder in $Srcfolders)
{
    $SrcFolderPath = $source -replace "\\","\\" -replace "\:","\:"
    $DesFolder = $folder.Fullname -replace $SrcFolderPath,$Destination
    if(!(test-path $DesFolder))
    {
        Write-Host "Folder $DesFolder Missing. Creating it!"
        new-Item $DesFolder -type Directory | out-Null
    }
}

# Checking for Folders that are in Destinatino, but not in Source
foreach($folder in $Desfolders)
{
    $DesFilePath = $Destination -replace "\\","\\" -replace "\:","\:"
    $SrcFolder = $folder.Fullname -replace $DesFilePath,$Source
    if(!(test-path $SrcFolder))
    {
        Write-Host "Folder $SrcFolder Missing. Creating it!"
        new-Item $SrcFolder -type Directory | out-Null
    }
}

# Checking for Files that are in the Source, but not in Destination
foreach($entry in $SrcFiles)
{
    $SrcFullname = $entry.fullname
    $SrcName = $entry.Name
    $SrcFilePath = $Source -replace "\\","\\" -replace "\:","\:"
    $DesFile = $SrcFullname -replace $SrcFilePath,$Destination
    if(test-Path $Desfile)
    {
        $SrcMD5 = Get-FileMD5 $SrcFullname
        $DesMD5 = Get-FileMD5 $DesFile
        If(Compare-Object $srcMD5 $desMD5)
        {
            Write-Host "The Files MD5's are Different... Checking Write
            Dates"
            Write-Host $SrcMD5
            Write-Host $DesMD5
            Copy-LatestFile $SrcFullname $DesFile
        }
    }
    else
    {
        Write-Host "$Desfile Missing... Copying from $SrcFullname"
        copy-Item -path $SrcFullName -dest $DesFile -force
    }
}

# Checking for Files that are in the Destinatino, but not in Source
foreach($entry in $DesFiles)
{
    $DesFullname = $entry.fullname
    $DesName = $entry.Name
    $DesFilePath = $Destination -replace "\\","\\" -replace "\:","\:"
    $SrcFile = $DesFullname -replace $DesFilePath,$Source
    if(!(test-Path $SrcFile))
    {
        Write-Host "$SrcFile Missing... Copying from $DesFullname"
        copy-Item -path $DesFullname -dest $SrcFile -force
    }
}
于 2009-03-24T16:04:45.850 回答
0

这是我在备份文件夹中仅复制新文件的解决方案

$ImagesFolder = 'D:\img temp\from'
$BackupImagesFolder = 'D:\img temp\to'

$ImagesFiles = Get-ChildItem -Path $ImagesFolder
$BackUpImagesFiles = (Get-ChildItem -Path $BackupImagesFolder).Name

foreach($image in $ImagesFiles)
{
    $fileName = $image.Name;
    if($BackUpImagesFiles -notcontains $fileName)
    {
        Copy-Item $image.FullName -Destination $BackupImagesFolder
    }
}

享受 ：）

于 2021-08-23T12:09:10.470 回答