count duplicates with PowerShell

Question

I want to count duplicates of files with PowerShell. My files have a special separator ('#') and I can only compare the part before the separator.

Mode        LastWriteTime   Length Name
----        -------------   ------ ----
-a----   23.09.2016 09:44        0 AnotherDuplicateOffer_#1265473v1.DOCX
-a----   23.09.2016 09:44        0 AnotherDuplicateOffer_#89798798546v1.DOCX
-a----   23.09.2016 09:44        0 AnotherDuplicateOffer_#98769876v1.DOCX
-a----   23.09.2016 09:44        0 DuplicateOffer_#1254798v1.DOCX
-a----   23.09.2016 09:44        0 DuplicateOffer_#34987094587v1.DOCX
-a----   23.09.2016 09:44        0 DuplicateOffer_#4986598v1.DOCX
-a----   23.09.2016 09:44        0 DuplicateOffer_#567809v1.DOCX
-a----   23.09.2016 09:44        0 WordFilesAlthoug_#89798798546v1.DOCX

The part after the separator is a unique ID and at least I want to rename the files by removing this ID. So the new filename should be something like 'string (x).docx' and the 'x' should a counter for the duplicates.

I'm stuck by counting the duplicates:

foreach ($file in (Get-ChildItem -Path $path -Recurse | Where {!$_.PSIsContainer})) {
    $file.Name
    $file.Name.IndexOf("#")
    $file.Name.Substring(0, ($file.Name.IndexOf("#")))
    (dir *.* | group -Property Name | Where {($_.Name.Substring(0,($_.Name.IndexOf("#")))) -match ($_.Name.Substring(0,($_.Name.IndexOf("#"))))}).Count
}

I get the right index of '#' with $file.Name.IndexOf("#") and also the string of $file.Name.Substring(0,($file.Name.IndexOf("#"))) is right. But when I use the same in the pipe I get exceptions in Substring because of the second part - this must be greater than 0 and it appears to be 0 or less.

For better understanding: $_ is the same as $file - it is the actual pointer in the pipe.

Ansgar Wiechers · Accepted Answer · 2016-10-03 12:26:02Z

3

Simply group the files by the first part of their name and select those groups that have more than one element.

Get-ChildItem -Path $path -Recurse |
    Where-Object { -not $_.PSIsContainer } |
    Group-Object { ($_.Name -split '#')[0] } |
    Where-Object { $_.Count -ge 2 }

Rename the files by processing each group separately:

... | ForEach-Object {
    $i = 0
    $_.Group | ForEach-Object {
        $newname = $_.Name -replace '#\d+v\d+', "($i)"
        Rename-Item -Path $_.FullName -NewName $newname
        $i++
    }
}

answered Oct 3, 2016 at 12:26

Ansgar Wiechers

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1 Comment

ludwigschuster Over a year ago

thanks that works either. Anyway, i got my Probelm solved by myself. see update above

ludwigschuster · Accepted Answer · 2016-10-03 20:52:56Z

0

Finally i got it working. The point was to give dir the right path. I didn't do this in the first time, because i thought this i given by my pointer $file but it is not. So giving the the right path is done with Parameter -Path and $file.Directory. This way dir gets the right path where the actuall $file is into.

(dir -Path $file.Directory *.* | group -Property Name | Where{($_.Name.Substring(0,($_.Name.IndexOf("#")))) -match ($_.Name.Substring(0,($_.Name.IndexOf("#"))))}).Count

answered Oct 3, 2016 at 20:52

ludwigschuster

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