Renaming files Powershell, Cannot rename file does not exist - regex

Question

I try to remove " - 13234" from a bunch of files recursively. And if the file is already present after removing that part it should add (1), (2) and so on after the new file name.
I tested it on a small set of files and that was working fine. Now I tried it on a larger test set and it gave me some errors.
Like: Cannot rename file does not exist
Like: Cannot create a file when file already exist
For a lot of files it looks like it is doing fine actually.
$files = Get-ChildItem <location> -recurse -file | sort name | group-object -property {$_.fullname -replace "(.*)-.*?(\..*?)$",'$1$2'}
$files | foreach {
$inc = 0
if ($_.count -gt 1) {
rename-item -literalpath $_.group[0].fullname -NewName (($_.group[0].basename -replace "(.*)-.*?$",'$1') + $_.group[0].extension)
$inc++
for ($i = $inc; $i -lt $_.count; $i++) {
rename-item -literalpath $_.group[$i].fullname -NewName (($_.group[$i].basename -replace "(.*)-.*?$",'$1') + "($i)" + $_.group[$i].extension)
}
}
else {
rename-item -literalpath $_.group.fullname -NewName (($_.group.basename -replace "(.*)-.*?$",'$1') + $_.group.extension)
}
}

Answer 1

If the following files are in the same directory, the script probably will not work.
1 - 13234.txt
1.txt
The script first tries to change "1 - 13234.txt" to "1. txt".
You had better first check the existence of the file.
Get-ChildItem -File -Recurse |
where BaseName -match "(.*)-" |
Group-Object { $_.DirectoryName + "\" + $Matches[1].TrimEnd() + $_.Extension } |
foreach {
$fi = [IO.FileInfo]::new($_.Name)
$i = 0
$_.Group | Rename-Item -NewName {
do {
$newName = $fi.DirectoryName + "\" + $fi.BaseName + $(if($i){"($i)"}) + $fi.Extension
$script:i++
} while (Test-Path $newName)
$newName
} -PassThru
}

Answer 2

I would do something like this:
$Path = '<PATH TO THE ROOTFOLDER WHERE THE FILES TO RENAME ARE FOUND>'
Get-ChildItem -Path $Path -Filter '*-*' -File -Recurse | ForEach-Object {
# obtain the new file basename
$newBaseName = ($_.BaseName -split '-')[0].Trim()
$extension = $_.Extension # this includes the dot
$folder = $_.DirectoryName
# get an array of all filenames (name only) of the files with a similar name already present in the folder
$allFiles = #(Get-ChildItem $folder -Filter "$newBaseName*$extension" -File | Select-Object -ExpandProperty Name)
# for PowerShell version < 3.0 use this
# $allFiles = #(Get-ChildItem $folder-Filter "$newBaseName*$extension" | Where-Object { !($_.PSIsContainer) } | Select-Object -ExpandProperty Name)
# construct the new filename
$newFileName = $newBaseName + $extension
if ($allFiles.Count) {
$count = 1
while ($allFiles -contains $newFileName) {
$newFileName = "{0}({1}){2}" -f $newBaseName, $count++, $extension
}
}
Write-Host "Renaming '$($_.FullName)' to '$newFileName'"
$_ | Rename-Item -NewName $newFileName -Force
}
Hope that helps