How to rename files with powershell if there are duplicate files? - powershell

Question

Get-ChildItem -Filter *_* | Foreach-Object -Process {
$NewName = [Regex]::Match($_.Name,"^[^ _]*").Value +'.jpg'
$_ | Rename-Item -NewName $NewName
}
I have been using this code to rename files
For example, 569_SOM_TEST.jpg to 569
but if there is 569_TOB_TEST.jpg, It gives an error Rename-Item : Cannot create a file when that file already exists.
I want it to make it 569-1.
How can I accomplish this?

Answer 1

To prevent renaming clashes, you can put the below helper function at the top of your script:
function Rename-FileUnique {
# Renames a file. If a file with that name already exists,
# the function will create a unique filename by appending '(x)' after the
# name, but before the extension. The 'x' is a numeric value.
[CmdletBinding()]
Param(
[Parameter(Mandatory = $true, ValueFromPipeline = $true, ValueFromPipelineByPropertyName = $true, Position = 0)]
[string]$Path,
[Parameter(Mandatory = $true, Position = 1)]
[string]$NewName,
[switch]$PassThru
)
# Throw a bit nicer error than with [ValidateScript({Test-Path -Path $_ -PathType Leaf})]
if (!(Test-Path -Path $Path -PathType Leaf)){
Throw [System.IO.FileNotFoundException] "Rename-FileUnique: The file '$Path' could not be found."
}
# split the new filename into a basename and an extension variable
$baseName = [System.IO.Path]::GetFileNameWithoutExtension($NewName)
$extension = [System.IO.Path]::GetExtension($NewName) # this includes the dot
$folder = Split-Path -Path $Path -Parent
# get an array of all filenames (name only) of the files with a similar name already present in the folder
$allFiles = #(Get-ChildItem $folder -Filter "$baseName*$extension" -File | Select-Object -ExpandProperty Name)
# for PowerShell version < 3.0 use this
# $allFiles = #(Get-ChildItem $folder -Filter "$baseName*$extension" | Where-Object { !($_.PSIsContainer) } | Select-Object -ExpandProperty Name)
# construct the new filename / strip the path from the file name
$NewName = $baseName + $extension # or use $NewName = Split-Path $NewName -Leaf
if ($allFiles.Count) {
$count = 1
while ($allFiles -contains $NewName) {
$NewName = "{0}-{1}{2}" -f $baseName, $count++, $extension
}
}
Write-Verbose "Renaming '$Path' to '$NewName'"
Rename-Item -Path $Path -NewName $NewName -Force -PassThru:$PassThru
}
and use it like:
Get-ChildItem -Filter '*_*.jpg' | Foreach-Object {
# create the proposed new filename
$newName = '{0}.jpg' -f ($_.Name -split '_')[0]
$_ | Rename-FileUnique -NewName $newName
}
This will ensure that any proposed new filename gets a not already used index number attached to its basename.