我认为您应该尝试以下方法，它可以根据您的要求更改syncMode。1是单向同步源到目标，2是双向同步

$source="The source folder" 
$target="The target folder" 

touch $source'initial.initial'
touch $target'initial.initial'

$sourceFiles=Get-ChildItem -Path $source -Recurse
$targetFiles=Get-ChildItem -Path $target -Recurse

$syncMode=2 

    try{
    $diff=Compare-Object -ReferenceObject $sourceFiles -DifferenceObject $targetFiles

    foreach($f in $diff) {
        if($f.SideIndicator -eq "<=") {
            $fullSourceObject=$f.InputObject.FullName
            $fullTargetObject=$f.InputObject.FullName.Replace($source, $target)

            Write-Host "Attemp to copy the following: " $fullSourceObject
            Copy-Item -Path $fullSourceObject -Destination $fullTargetObject
        }

        if($f.SideIndicator -eq "=>" -and $syncMode -eq 2) {
            $fullSourceObject=$f.InputObject.FullName
            $fullTargetObject=$f.InputObject.FullName.Replace($target,$source)

            Write-Host "Attemp to copy the following: " $fullSourceObject
            Copy-Item -Path $fullSourceObject -Destination $fullTargetObject
        }

    }
    }      
    catch {
    Write-Error -Message "something bad happened!" -ErrorAction Stop
    }
    rm $source'initial.initial'
    rm $target'initial.initial'

除了前面的答案，这篇关于比较文件的方法的文章可能也会有帮助。实际上，按内容比较文件需要一个额外的步骤。（如散列）。此方法的详细说明写在这里：https://mcpmag.com/articles/2016/04/14/contents-of-two-folders-with-powershell.aspx

这是一个完整的CLI，用于保持一种同步方式

# Script will sync $source_folder into $target_folder and delete non relevant files. 
# If $target_folder doesn't exist it will be created. 

param ($source_folder, $target_folder, $cleanup_target = "TRUE", $log_file = "sync.log")

function Write-Log {
    Param ([string]$log_string, [string]$log_level = "INFO")
    $time_stamp = (Get-Date).toString("dd-MM-yyyy HH:mm:ss")
    $log_message = "$time_stamp [$log_level] $log_string"
    Add-content $log_file -value $log_message
    if ($log_level = "INFO") {
        Write-Host $log_message
    }
    elseif ($log_level = "ERROR") {
        Write-Error $log_message
    }
    elseif ($log_level = "WARNING") {
        Write-Warning $log_message
    }
    else {
        Write-Error "Wrong log level: $log_level"
        exit 1
    }
}

if (!(Test-Path -Path $source_folder -PathType Container)) {
    Write-Log "Source folder doesn't exist: $source_folder" "ERROR"
    exit 1
}

if (Test-Path -Path $target_folder -PathType Leaf) {
    Write-Log"Target object is file. Can't create target folder with the same name: $target_folder" "ERROR"
    exit 1
}

$source_content = Get-ChildItem -Path $source_folder -Recurse
if ($null -eq $source_content) { 
    $source_content = [array]
}

$target_content = Get-ChildItem -Path $target_folder -Recurse
if ($null -eq $target_content) { 
    $target_content = [array]
}

Write-Log "************************** Started syncing $source_folder >> $target_folder **************************"

$differences = Compare-Object -ReferenceObject $source_content -DifferenceObject $target_content

foreach ($difference in $differences) {
    if ($difference.SideIndicator -eq "<=") {
        $source_object_path = $difference.InputObject.FullName
        $target_object_path = $source_object_path.Replace($source_folder, $target_folder)
        if (Test-Path -Path $source_object_path -PathType Leaf) {
            $hash_source_file = (Get-FileHash $source_object_path -Algorithm SHA256).Hash
            if (Test-Path -Path $target_object_path -PathType Leaf) {
                $hash_target_file = (Get-FileHash $target_object_path -Algorithm SHA256).Hash
            }
            else {
                $hash_target_file = $null
            }
            if ( $hash_source_file -ne $hash_target_file ) {
                Write-Log "Synced file $source_object_path >> $target_object_path"
                Copy-Item -Path $source_object_path -Destination $target_object_path
            }
            else {
                Write-Log "Same file, will not sync $source_object_path >> $target_object_path"
            }
        }
        elseif (Test-Path -Path $target_object_path -PathType Container) {
            Write-Log "Folder already exists, will not sync $source_object_path >> $target_object_path"
        }
        else {
            Write-Log "Synced folder $source_object_path >> $target_object_path"
            Copy-Item -Path $source_object_path -Destination $target_object_path
        }        
    }
    elseif (($difference.SideIndicator -eq "=>") -and $cleanup_target -eq "TRUE") {
        $target_object_path = $difference.InputObject.FullName
        $source_object_path = $target_object_path.Replace($target_folder, $source_folder)
        if (!(Test-Path -Path $source_object_path) -and (Test-Path -Path $target_object_path)) {
            Remove-Item -Path $target_object_path -Recurse -Force
            Write-Log "Removed $target_object_path"
        }
    }
}
Write-Log "************************** Ended syncing $source_folder >> $target_folder **************************"

你看过Robocopy（鲁棒的文件复制）吗？它可以与PS一起使用，并提供你所寻找的iidoEe。它是专为文件夹的可靠复制或镜像（更改/添加/删除）而设计的，只需根据需要选择选项。
Robocopy sourceFolder destinationFolder /MIR /FFT /Z /XA:H /W:5
/MIR选项镜像源目录和目标目录。如果在源目录中删除了文件，它将删除目标目录中的文件。
Robocopy