Functions/GenXdev.FileSystem/Find-DuplicateFiles.ps1
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Part of PowerShell module : GenXdev.FileSystem Original cmdlet filename : Find-DuplicateFiles.ps1 Original author : René Vaessen / GenXdev Version : 1.264.2025 ################################################################################ MIT License Copyright 2021-2025 GenXdev Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. ################################################################################> ############################################################################### <# .SYNOPSIS Find duplicate files across multiple directories based on configurable criteria. .DESCRIPTION Recursively searches specified directories for duplicate files. Files are considered duplicates if they share the same name and optionally match on size and modification date. Returns groups of duplicate files for further processing. .PARAMETER Paths Array of directory paths to recursively search for duplicate files. Accepts pipeline input and wildcard paths. .PARAMETER DontCompareSize When specified, file size is not used as a comparison criterion, only names are matched. .PARAMETER DontCompareModifiedDate When specified, file modification dates are not used as a comparison criterion. .EXAMPLE Find-DuplicateFiles -Paths "C:\Photos","D:\Backup\Photos" .EXAMPLE "C:\Photos","D:\Backup\Photos" | fdf -DontCompareSize #> function Find-DuplicateFiles { [CmdletBinding()] [System.Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSUseSingularNouns', '')] [Alias('fdf')] param( ############################################################################### [Parameter( Mandatory = $true, Position = 0, ValueFromPipeline = $true, ValueFromPipelineByPropertyName = $true, HelpMessage = 'One or more directory paths to search for duplicates' )] [string[]] $Paths, ############################################################################### [Parameter( Mandatory = $false, Position = 1, HelpMessage = 'Skip file size comparison when grouping duplicates' )] [switch] $DontCompareSize, ############################################################################### [Parameter( Mandatory = $false, Position = 2, HelpMessage = 'Skip last modified date comparison when grouping duplicates' )] [switch] $DontCompareModifiedDate ############################################################################### ) begin { # convert all input paths to full filesystem paths $normalizedPaths = @() $Paths | Microsoft.PowerShell.Core\ForEach-Object { $normalizedPaths += (GenXdev.FileSystem\Expand-Path $_) } # internal helper function to generate unique comparison key for each file function Get-FileKey([System.IO.FileInfo]$file) { # start with filename as the base identifier $key = $file.Name # include file size in comparison key if enabled if (-not $DontCompareSize) { $key += "|$($file.Length)" } # include modification date in comparison key if enabled if (-not $DontCompareModifiedDate) { $key += "|$($file.LastWriteTimeUtc.ToString('o'))" } return $key } # initialize high-performance collection for gathering files $allFiles = [System.Collections.Generic.List[System.IO.FileInfo]]::new() } process { foreach ($path in $normalizedPaths) { # verify directory exists before attempting to process if ([System.IO.Directory]::Exists($path)) { Microsoft.PowerShell.Utility\Write-Verbose "Scanning directory for duplicates: $path" # use direct .NET IO for faster recursive file enumeration [System.IO.Directory]::GetFiles($path, '*.*', [System.IO.SearchOption]::AllDirectories) | Microsoft.PowerShell.Core\ForEach-Object { $null = $allFiles.Add([System.IO.FileInfo]::new($_)) } } else { Microsoft.PowerShell.Utility\Write-Warning "Skipping non-existent directory: $path" } } } end { # group files by composite key and return only groups with duplicates $allFiles | Microsoft.PowerShell.Utility\Group-Object -Property { Get-FileKey $_ } | Microsoft.PowerShell.Core\Where-Object { $_.Count -gt 1 } | Microsoft.PowerShell.Core\ForEach-Object { # create result object for each duplicate group [PSCustomObject]@{ FileName = $_.Group[0].Name Files = $_.Group } } } } |