How can I use powershell to copy files into subfolders based on whether or not the file size is unique?

Question

I have a folder full of .wav files that I'd like to copy into subfolders called "Unique Size" and "Non-Unique Size". Around half of the files are the same size down to the byte:

Get-ChildItem "*.wav" | Group-Object -Property Length -NoElement | Sort-Object Count -Descending

Count Name     Group (Example)
----- ----     ----
    6 26244078 {file206.wav, file137.wav, file 101.wav, etc.}
    5 28716602
    5 28807758
    5 30750266
    ...
    1 17773794 {file31.wav}
    1 18144078
    1 18432082
    1 70589446

I'd like them to be copied into "Unique Size" if Group Count = 1 and "Non-Unique Size" otherwise, but I'm fairly inexperienced with powershell and CLI in general and I'm not really sure what to do with the output of the command at this point. I have tried a few searches online but my keywords don't seem to be getting me anywhere for this rather unique problem. Any help is appreciated, thank you!

Answer 1

What you need is to loop over the groups and depending on their .Count property copy the files to either the Unique Size or the Non-Unique Size folders.

$sourcePath    = 'X:\path\to\all\wav\files'
$uniquePath    = 'X:\path\to\Unique Size'
$differentPath = 'X:\path\to\Non-Unique Size'

Get-ChildItem -Path $sourcePath -Filter '*.wav' -File | Group-Object -Property Length | ForEach-Object {
    $destination = if ($_.Count -gt 1) {$differentPath} else {$uniquePath}
    foreach ($file in $_.Group) {
        $file | Copy-Item -Destination $destination
    }
}