使用 PowerShell 比较文件夹和内容

Question

我有两个不同的文件夹，其中包含 xml 文件。与另一个文件夹（folder1）相比，一个文件夹（folder2）包含更新的和新的 xml 文件。我需要知道与folder1 相比，folder2 中的哪些文件是新的/更新的，并将它们复制到第三个文件夹（folder3）。在 PowerShell 中实现此目的的最佳方法是什么？

Answer 1

好吧，我不会为您编写整个代码（这有什么乐趣？），但我会帮助您开始。

首先，有两种方法可以进行内容比较。懒惰/最正确的方法是比较文件的长度；准确但更复杂的方法是比较每个文件内容的哈希值。

为了简单起见，让我们采用简单的方法来比较文件大小。

基本上，您需要两个对象来代表源文件夹和目标文件夹：

$Folder1 = Get-childitem "C:\Folder1"
$Folder2 = Get-childitem  "C:\Folder2"

然后您可以使用Compare-Object 来查看哪些项目不同...

Compare-Object $Folder1 $Folder2 -Property Name , Length

它将通过仅比较每个集合中文件对象的名称和长度来为您列出所有不同的内容。

您可以将其通过管道传输到 Where-Object 过滤器，以选择左侧不同的内容...

Compare-Object $Folder1 $Folder2 -Property Name, Length | Where-Object {$_.SideIndicator -eq "<="}

然后将其通过管道传输到 ForEach-Object 以复制您想要的位置：

Compare-Object $Folder1 $Folder2 -Property Name, Length  | Where-Object {$_.SideIndicator -eq "<="} | ForEach-Object {
        Copy-Item "C:\Folder1\$($_.name)" -Destination "C:\Folder3" -Force
        }

Answer 2

使用 MD5 哈希的递归目录差异（比较内容）

这是一个纯 PowerShell v3+ 递归文件差异（无依赖项），用于计算每个目录文件内容（左/右）的 MD5 哈希。可以选择导出 CSV 以及摘要文本文件。默认将结果输出到标准输出。可以将 rdiff.ps1 文件放入您的路径或将内容复制到您的脚本中。

用法：rdiff path/to/left,path/to/right [-s path/to/summary/dir]

这是要点。建议使用要点版本，因为随着时间的推移它可能会具有附加功能。请随意发送拉取请求。

#########################################################################
### USAGE: rdiff path/to/left,path/to/right [-s path/to/summary/dir]  ###
### ADD LOCATION OF THIS SCRIPT TO PATH                               ###
#########################################################################
[CmdletBinding()]
param (
  [parameter(HelpMessage="Stores the execution working directory.")]
  [string]$ExecutionDirectory=$PWD,

  [parameter(Position=0,HelpMessage="Compare two directories recursively for differences.")]
  [alias("c")]
  [string[]]$Compare,

  [parameter(HelpMessage="Export a summary to path.")]
  [alias("s")]
  [string]$ExportSummary
)

### FUNCTION DEFINITIONS ###

# SETS WORKING DIRECTORY FOR .NET #
function SetWorkDir($PathName, $TestPath) {
  $AbsPath = NormalizePath $PathName $TestPath
  Set-Location $AbsPath
  [System.IO.Directory]::SetCurrentDirectory($AbsPath)
}

# RESTORES THE EXECUTION WORKING DIRECTORY AND EXITS #
function SafeExit() {
  SetWorkDir /path/to/execution/directory $ExecutionDirectory
  Exit
}

function Print {
  [CmdletBinding()]
  param (
    [parameter(Mandatory=$TRUE,Position=0,HelpMessage="Message to print.")]
    [string]$Message,

    [parameter(HelpMessage="Specifies a success.")]
    [alias("s")]
    [switch]$SuccessFlag,

    [parameter(HelpMessage="Specifies a warning.")]
    [alias("w")]
    [switch]$WarningFlag,

    [parameter(HelpMessage="Specifies an error.")]
    [alias("e")]
    [switch]$ErrorFlag,

    [parameter(HelpMessage="Specifies a fatal error.")]
    [alias("f")]
    [switch]$FatalFlag,

    [parameter(HelpMessage="Specifies a info message.")]
    [alias("i")]
    [switch]$InfoFlag = !$SuccessFlag -and !$WarningFlag -and !$ErrorFlag -and !$FatalFlag,

    [parameter(HelpMessage="Specifies blank lines to print before.")]
    [alias("b")]
    [int]$LinesBefore=0,

    [parameter(HelpMessage="Specifies blank lines to print after.")]
    [alias("a")]
    [int]$LinesAfter=0,

    [parameter(HelpMessage="Specifies if program should exit.")]
    [alias("x")]
    [switch]$ExitAfter
  )
  PROCESS {
    if($LinesBefore -ne 0) {
      foreach($i in 0..$LinesBefore) { Write-Host "" }
    }
    if($InfoFlag) { Write-Host "$Message" }
    if($SuccessFlag) { Write-Host "$Message" -ForegroundColor "Green" }
    if($WarningFlag) { Write-Host "$Message" -ForegroundColor "Orange" }
    if($ErrorFlag) { Write-Host "$Message" -ForegroundColor "Red" }
    if($FatalFlag) { Write-Host "$Message" -ForegroundColor "Red" -BackgroundColor "Black" }
    if($LinesAfter -ne 0) {
      foreach($i in 0..$LinesAfter) { Write-Host "" }
    }
    if($ExitAfter) { SafeExit }
  }
}

# VALIDATES STRING MIGHT BE A PATH #
function ValidatePath($PathName, $TestPath) {
  If([string]::IsNullOrWhiteSpace($TestPath)) {
    Print -x -f "$PathName is not a path"
  }
}

# NORMALIZES RELATIVE OR ABSOLUTE PATH TO ABSOLUTE PATH #
function NormalizePath($PathName, $TestPath) {
  ValidatePath "$PathName" "$TestPath"
  $TestPath = [System.IO.Path]::Combine((pwd).Path, $TestPath)
  $NormalizedPath = [System.IO.Path]::GetFullPath($TestPath)
  return $NormalizedPath
}


# VALIDATES STRING MIGHT BE A PATH AND RETURNS ABSOLUTE PATH #
function ResolvePath($PathName, $TestPath) {
  ValidatePath "$PathName" "$TestPath"
  $ResolvedPath = NormalizePath $PathName $TestPath
  return $ResolvedPath
}

# VALIDATES STRING RESOLVES TO A PATH AND RETURNS ABSOLUTE PATH #
function RequirePath($PathName, $TestPath, $PathType) {
  ValidatePath $PathName $TestPath
  If(!(Test-Path $TestPath -PathType $PathType)) {
    Print -x -f "$PathName ($TestPath) does not exist as a $PathType"
  }
  $ResolvedPath = Resolve-Path $TestPath
  return $ResolvedPath
}

# Like mkdir -p -> creates a directory recursively if it doesn't exist #
function MakeDirP {
  [CmdletBinding()]
  param (
    [parameter(Mandatory=$TRUE,Position=0,HelpMessage="Path create.")]
    [string]$Path
  )
  PROCESS {
    New-Item -path $Path -itemtype Directory -force | Out-Null
  }
}

# GETS ALL FILES IN A PATH RECURSIVELY #
function GetFiles {
  [CmdletBinding()]
  param (
    [parameter(Mandatory=$TRUE,Position=0,HelpMessage="Path to get files for.")]
    [string]$Path
  )
  PROCESS {
    ls $Path -r | where { !$_.PSIsContainer }
  }
}

# GETS ALL FILES WITH CALCULATED HASH PROPERTY RELATIVE TO A ROOT DIRECTORY RECURSIVELY #
# RETURNS LIST OF @{RelativePath, Hash, FullName}
function GetFilesWithHash {
  [CmdletBinding()]
  param (
    [parameter(Mandatory=$TRUE,Position=0,HelpMessage="Path to get directories for.")]
    [string]$Path,

    [parameter(HelpMessage="The hash algorithm to use.")]
    [string]$Algorithm="MD5"
  )
  PROCESS {
    $OriginalPath = $PWD
    SetWorkDir path/to/diff $Path
    GetFiles $Path | select @{N="RelativePath";E={$_.FullName | Resolve-Path -Relative}},
                            @{N="Hash";E={(Get-FileHash $_.FullName -Algorithm $Algorithm | select Hash).Hash}},
                            FullName
    SetWorkDir path/to/original $OriginalPath
  }
}

# COMPARE TWO DIRECTORIES RECURSIVELY #
# RETURNS LIST OF @{RelativePath, Hash, FullName}
function DiffDirectories {
  [CmdletBinding()]
  param (
    [parameter(Mandatory=$TRUE,Position=0,HelpMessage="Directory to compare left.")]
    [alias("l")]
    [string]$LeftPath,

    [parameter(Mandatory=$TRUE,Position=1,HelpMessage="Directory to compare right.")]
    [alias("r")]
    [string]$RightPath
  )
  PROCESS {
    $LeftHash = GetFilesWithHash $LeftPath
    $RightHash = GetFilesWithHash $RightPath
    diff -ReferenceObject $LeftHash -DifferenceObject $RightHash -Property RelativePath,Hash
  }
}

### END FUNCTION DEFINITIONS ###

### PROGRAM LOGIC ###

if($Compare.length -ne 2) {
  Print -x "Compare requires passing exactly 2 path parameters separated by comma, you passed $($Compare.length)." -f
}
Print "Comparing $($Compare[0]) to $($Compare[1])..." -a 1
$LeftPath   = RequirePath path/to/left $Compare[0] container
$RightPath  = RequirePath path/to/right $Compare[1] container
$Diff       = DiffDirectories $LeftPath $RightPath
$LeftDiff   = $Diff | where {$_.SideIndicator -eq "<="} | select RelativePath,Hash
$RightDiff   = $Diff | where {$_.SideIndicator -eq "=>"} | select RelativePath,Hash
if($ExportSummary) {
  $ExportSummary = ResolvePath path/to/summary/dir $ExportSummary
  MakeDirP $ExportSummary
  $SummaryPath = Join-Path $ExportSummary summary.txt
  $LeftCsvPath = Join-Path $ExportSummary left.csv
  $RightCsvPath = Join-Path $ExportSummary right.csv

  $LeftMeasure = $LeftDiff | measure
  $RightMeasure = $RightDiff | measure

  "== DIFF SUMMARY ==" > $SummaryPath
  "" >> $SummaryPath
  "-- DIRECTORIES --" >> $SummaryPath
  "`tLEFT -> $LeftPath" >> $SummaryPath
  "`tRIGHT -> $RightPath" >> $SummaryPath
  "" >> $SummaryPath
  "-- DIFF COUNT --" >> $SummaryPath
  "`tLEFT -> $($LeftMeasure.Count)" >> $SummaryPath
  "`tRIGHT -> $($RightMeasure.Count)" >> $SummaryPath
  "" >> $SummaryPath
  $Diff | Format-Table >> $SummaryPath

  $LeftDiff | Export-Csv $LeftCsvPath -f
  $RightDiff | Export-Csv $RightCsvPath -f
}
$Diff
SafeExit

Answer 3

除了@JNK 的回答之外，您可能希望确保始终使用文件而不是 Compare-Object 的不太直观的输出。您只需要使用 -PassThru 开关...

$Folder1 = Get-ChildItem "C:\Folder1"
$Folder2 = Get-ChildItem "C:\Folder2"
$Folder2 = "C:\Folder3\"

# Get all differences, i.e. from both "sides"
$AllDiffs = Compare-Object $Folder1 $Folder2 -Property Name,Length -PassThru

# Filter for new/updated files from $Folder2
$Changes = $AllDiffs | Where-Object {$_.Directory.Fullname -eq $Folder2}

# Copy to $Folder3
$Changes | Copy-Item -Destination $Folder3

这至少意味着您不必担心 SideIndicator 箭头指向哪个方向！

另外，请记住，您可能还想比较 LastWriteTime。

子文件夹

递归地循环子文件夹稍微复杂一些，因为在比较列表之前您可能需要从 FullName 字段中删除相应的根文件夹路径。

您可以通过向您的Folder1和Folder2列表添加一个新的ScriptProperty来完成此操作：

$Folder1 | Add-Member -MemberType ScriptProperty -Name "RelativePath" `
  -Value {$this.FullName -replace [Regex]::Escape("C:\Folder1"),""}

$Folder2 | Add-Member -MemberType ScriptProperty -Name "RelativePath" `
  -Value {$this.FullName -replace [Regex]::Escape("C:\Folder2"),""}

然后您应该能够在比较两个对象时使用RelativePath作为属性，并使用它来连接到“C: \Folder3" 复制时保持文件夹结构不变。

Answer 4

这是一种可以查找丢失或内容不同的文件的方法。

首先，快速而肮脏的一句台词（见下面的警告）。

dir -r | rvpa -Relative |%{ if (Test-Path $right\$_) { if (Test-Path -Type Leaf $_) { if ( diff (cat $_) (cat $right\$_ ) ) { $_ } } } else { $_ } }

在其中一个目录中运行上述命令，并将 $right 设置为（或替换为）另一个目录的路径。 $right 中缺少的内容或内容不同的内容将被报告。没有输出意味着没有发现差异。 警告：$right中存在但左侧缺失的事物将不会被发现/报告。

这不会影响计算哈希值；它只是直接比较文件内容。当您想要在另一个上下文中（稍后的日期，在另一台机器上等）引用某些内容时，散列是有意义的，但是当我们直接比较事物时，它只会增加开销。 （理论上两个文件也可能具有相同的哈希值，尽管这基本上不可能偶然发生。另一方面，故意攻击......）

这是一个更合适的脚本，它可以处理更多的极端情况和错误。

[CmdletBinding()]
Param(
    [Parameter(Mandatory=$true,Position=0)][string]$Left,
    [Parameter(Mandatory=$True,Position=1)][string]$Right
    )

# throw errors on undefined variables
Set-StrictMode -Version 1

# stop immediately on error
$ErrorActionPreference = [System.Management.Automation.ActionPreference]::Stop

# init counters
$Items = $MissingRight = $MissingLeft = $Contentdiff = 0

# make sure the given parameters are valid paths
$left  = Resolve-Path $left
$right = Resolve-Path $right

# make sure the given parameters are directories
if (-Not (Test-Path -Type Container $left))  { throw "not a container: $left"  }
if (-Not (Test-Path -Type Container $right)) { throw "not a container: $right" }

# Starting from $left as relative root, walk the tree and compare to $right.
Push-Location $left

try {
    Get-ChildItem -Recurse | Resolve-Path -Relative | ForEach-Object {
        $rel = $_
        
        $Items++
        
        # make sure counterpart exists on the other side
        if (-not (Test-Path $right\$rel)) {
            Write-Output "missing from right: $rel"
            $MissingRight++
            return
            }
    
        # compare contents for files (directories just have to exist)
        if (Test-Path -Type Leaf $rel) {
            if ( Compare-Object (Get-Content $left\$rel) (Get-Content $right\$rel) ) {
                Write-Output "content differs   : $rel"
                $ContentDiff++
                }
            }
        }
    }
finally {
    Pop-Location
    }

# Check items in $right for counterparts in $left.
# Something missing from $left of course won't be found when walking $left.
# Don't need to check content again here.

Push-Location $right

try {
    Get-ChildItem -Recurse | Resolve-Path -Relative | ForEach-Object {
        $rel = $_
        
        if (-not (Test-Path $left\$rel)) {
            Write-Output "missing from left : $rel"
            $MissingLeft++
            return
            }
        }
    }
finally {
    Pop-Location
    }

Write-Verbose "$Items items, $ContentDiff differed, $MissingLeft missing from left, $MissingRight from right"

Answer 5

这样做：

compare (Get-ChildItem D:\MyFolder\NewFolder) (Get-ChildItem \\RemoteServer\MyFolder\NewFolder)

甚至递归：

compare (Get-ChildItem -r D:\MyFolder\NewFolder) (Get-ChildItem -r \\RemoteServer\MyFolder\NewFolder)

甚至很难忘记:)

Answer 6

使用脚本参数的方便版本

简单的文件级比较

调用它就像 PS > .\DirDiff.ps1 -a .\Old\ -b .\New\

Param(
  [string]$a,
  [string]$b
)

$fsa = Get-ChildItem -Recurse -path $a
$fsb = Get-ChildItem -Recurse -path $b
Compare-Object -Referenceobject $fsa -DifferenceObject $fsb

可能的输出：

InputObject                  SideIndicator
-----------                  -------------
appsettings.Development.json <=
appsettings.Testing.json     <=
Server.pdb                   =>
ServerClientLibrary.pdb      =>

Answer 7

gci -path 'C:\Folder' -recurse |where{$_.PSIsContainer}

-recurse 将探索给定根路径下的所有子树，而 .PSIsContainer 属性是您想要测试的属性，以仅获取所有文件夹。您可以仅将 where{!$_.PSIsContainer} 用于文件。