EliminateDuplicateFiles.ps1

# After a botched Windows file history process a few years ago, many of my 
# photos files ended up being duplicated (sometimes several times). This
# script hunts down duplicates by name and size and deletes the one
# with the longer name. Examples:
# IMG_2825.JPG and IMG_2825 (2015_03_26 01_58_35 UTC).JPG
# IMG_2199.JPG, IMG_2199-1.JPG, IMG_2199 (2014_10_13 02_31_59 UTC).JPG, IMG_2199-1 (2014_10_13 02_31_59 UTC).JPG

$startDir = "c:\temp\Photos"

(Get-ChildItem -Path $startDir -Recurse) | ForEach-Object {
    $dir = $_.FullName

    (Get-ChildItem -Path $dir -Filter "*.JPG") | Sort-Object -Descending | Where-Object {$_.Name.Length -eq 12} | ForEach-Object {
        $duplicated = $_.Name
        $duplicatedLength = $_.Length
        Write-Host "Evaluating $duplicated..."

        (Get-ChildItem -Path $dir -Filter "$($duplicated.Substring(0,8))*.JPG") | ForEach-Object {
            # `-Exclude $duplicated` in the Get-ChildItem command isn't working - 
            # for some reason it excludes all files :-(

            if ($_.Name -ne $duplicated -and $_.Length -eq $duplicatedLength) {
                Write-Host "Delete $($_.Name)"
                Remove-Item -Path $_.FullName -Force
            }
        }
    }
}