如果项目不存在，则将项目从源复制到目标

Question

我有一个非常基本的 powershell 复制脚本，可以将项目从源文件夹复制到目标文件夹。但是，这移动了太多数据，我想检查文件名是否已经存在，以便可以忽略该文件。我不需要像验证创建日期/校验和/等那样复杂。

目前是这样的：

Copy-Item source destination -recurse
Copy-Item source2 destination2 -recurse

我想我需要添加 Test-Path cmdlet，但我不确定如何实现它。

Answer 1

为此，您可以随时从PowerShell 致电ROBOCOPY。

使用 /xc（排除更改）/xn（排除较新）和 /xo（排除较旧）标志：

robocopy /xc /xn /xo source destination 

这只会复制那些不在目标文件夹中的文件。

更多选项请输入robocopy /?

Answer 2

$exclude = Get-ChildItem -recurse $dest
Copy-Item -Recurse $file $dest -Verbose -Exclude $exclude

Answer 3

虽然我同意 Robocopy 是解决此类问题的最佳工具，但我完全愿意为客户提供他们所要求的东西，这是一个有趣的 PowerShell 练习。

这个脚本应该按照您的要求做：仅当目标中不存在文件时，才将文件从源复制到目标，并且需要最少的装饰。由于您在示例中使用了 -recurse 选项，因此与仅测试目标文件夹中的文件名相比，这需要更多的编码。

$Source = "C:\SourceFolder"
$Destination = "C:\DestinationFolder"

Get-ChildItem $Source -Recurse | ForEach {
    $ModifiedDestination = $($_.FullName).Replace("$Source","$Destination")
    If ((Test-Path $ModifiedDestination) -eq $False) {
        Copy-Item $_.FullName $ModifiedDestination
        }
    }

Answer 4

以 Wai Ha Lee 的帖子为基础，下面是一个对我有用的示例：

$Source = "<your path here>"
$Dest = "<your path here>"
$Exclude = Get-ChildItem -recurse $Dest

Get-ChildItem $Source -Recurse -Filter "*.pdf" | Copy-Item -Destination $Dest -Verbose -Exclude $Exclude

这会构建一个要排除的列表，然后将源目录和子目录中的任何 pdf 复制到目标单个文件夹中...排除现有文件。同样，这是我需要的一个示例，但与您的类似。应该很容易调整到您的内心满足感。

Answer 5

函数Copy-IfNotPresent 一次只接受一个文件，但很容易循环查找要复制的所有文件。这是一个例子：

gci c:\temp\1\*.* -Recurse -File | % { Copy-IfNotPresent -FilePath $_ -Destination "C:\temp\2\$(Resolve-Path $_ -relative)" -Verbose }

这是函数。如有必要，它将生成文件夹树。这是要点链接：https://gist.github.com/pollusb/cd47b4afeda8edbf8943a8808c880eb8

Function Copy-IfNotPresent {
<#
    Copy file only if not present at destination.
    This is a one file at a time call. It's not meant to replace complex call like ROBOCOPY.
    Destination can be a file or folder. If it's a folder, you can use -Container to force Folder creation when not exists
#>
[CmdletBinding()]
Param (
    [Parameter(Mandatory)]
    $FilePath,

    [Parameter(Mandatory)]
    [string]$Destination,

    [switch]$Container,

    [switch]$WhatIf
)
#region validations
if ($FilePath -isnot [System.IO.FileInfo]){
    $File = Get-ChildItem $FilePath -File
} else {
    $File = $FilePath
}

if (!$File.Count){
    Write-Warning "$FilePath no file found."
    return
} elseif ($File.Count -gt 1) {
    Write-Warning "$FilePath must resolve to one file only."
    return
}
#endregion

# Destination is a folder
if ($Container -or (Test-Path -Path $Destination -PathType Container)) {
    if (!(Test-Path $Destination)) {
        New-Item -Path $Destination -ItemType Container | Out-Null
    }
    $Destination += "\$($File.Name)"
}

# Destination is a file
if (!(Test-Path $Destination)) {
    if ($WhatIf) {
        Write-Host "WhatIf:Copy-IfNotPresent $FilePath -> $Destination"
    } else {
        # Force creation of parent folder
        $Parent = Split-Path $Destination -Parent
        if (!(Test-Path $Parent)) { 
            New-Item $Parent -ItemType Container | Out-Null
        }
        Copy-Item -Path $FilePath -Destination $Destination  
        Write-Verbose "Copy-IfNotPresent $FilePath -> $Destination (is absent) copying"
    }
} else {
    Write-Verbose "Copy-IfNotPresent $Destination (is present) not copying"
}
}

Answer 6

$source = "c:\source"

$destination = "c:\destination"

1. 创建要排除的文件列表，即目标中已存在的文件。

$exclude = Get-Childitem -Recurse $destination | ForEach-Object { $_.FullName -replace [Regex]::Escape($destination ), "" }

1. 递归地将所有内容从source复制到destination，不包括之前收集的文件。

Copy-Item -Recurse -Path (Join-Path $source "*") -Destination $destination -Exclude $exclude -Force -Verbose

• (Join-Path $source "*") 在末尾添加一个通配符，确保您获得 source 文件夹的子文件夹，而不是源文件夹本身。
• 使用Force 是因为我不介意已经存在文件夹（导致错误消息）。 谨慎使用。
• ForEach-Object { $_.FullName -replace [Regex]::Escape($destination ), "" } 将现有文件全名转换为可用作Exclude 参数的值

Answer 7

这是一个递归脚本，它同步 2 个文件夹，忽略现有文件：

function Copy-FilesAndFolders([string]$folderFrom, [string]$folderTo) {
    $itensFrom = Get-ChildItem $folderFrom
    foreach ($i in $itensFrom) 
    {
        if ($i.PSIsContainer)
        {
            $subFolderFrom = $folderFrom + "\" + $i.BaseName
            $subFolderTo = $folderTo + "\" + $i.BaseName
            Copy-FilesAndFolders $subFolderFrom $subFolderTo | Out-Null
        }
        else
        {
            $from = $folderFrom + "\" + $i.Name
            $to = $folderTo + "\" + $i.Name
            if (!(Test-Path $from)) # only copies non-existing files
            {
                if (!(Test-Path $folderTo)) # if folder doesn't exist, creates it
                {
                    New-Item -ItemType "directory" -Path $folderTo
                }
                Copy-Item $from $folderTo
            }           
        }
    }   
}

称呼它：

Copy-FilesAndFolders "C:\FromFolder" "C:\ToFolder"

Answer 8

这里有很多很好的答案，这是我的贡献，因为它与保持 mp3 播放器与音乐库同步。

#Tom Hubbard, 10-19-2021
#Copy only new music to mp3 player, saves time by only copying items that don't exist on the destination.
#Leaving the hardcoded directories and paths in here, sometimes too much variable substitution is confusing for newer PS users.

#Gets all of the albums in the source directory such as your music library
$albumsInLibrary = gci -Directory -path "C:\users\tom\OneDrive\Music" | select -ExpandProperty Name

#Gets all of the albums of your destination folder, such as your mp3 player
$albumsOnPlayer = gci -Directory -Path "e:\" | select -ExpandProperty name

#For illustration, it will list the differences between the music library and the music player.
Compare-Object -DifferenceObject $albumsInLibrary -ReferenceObject $albumsOnPlayer

#Loop through each album in the library
foreach ($album in $albumsInLibrary)
{
    #Check to see if the music player contains this directory from the music library
    if ($albumsOnPlayer -notcontains $album)
{
    #If the album doesn't exist on the music player, copy it and it's child items from the library to the player
    write-host "$album is not on music player, copying to music player" -ForegroundColor Cyan
    Copy-Item -path "C:\users\Tom\OneDrive\music\$album" -Recurse -Destination e:\$album
}
}