A Windows powershell script to rename many files (within subfolders)

rename_for_plex.ps1

# I recommend commenting out the `Rename-Item` line and testing, before you actually bulk rename anything


# Recurse from the active directory
Get-ChildItem '.' -Recurse | ForEach-Object {
    # Don't rename folders, just files
    if ($_ -is [System.IO.FileInfo]) {
    
        # The original filepath (full path)
        $oldpath = $_.FullName
        
        # Your own logic here to build the new filename
        # Make sure to create a NAME, not a path
        $epNum = $_.Name.Substring($_.Name.Length - 7, 3)
        $newName = 'Dragon Ball Z Kai ' + 's01e' + $epNum + '.mkv'
        
        # Use `LiteralPath` instead of `Path`, to avoid all kinds of wildcard interpretations etc
        Rename-Item -LiteralPath $oldpath -NewName $newName
        
        # Print to terminal
        $newName
    }
}



# If you want to recurse all but a few directories, you can exclude them with this syntax
Get-ChildItem -Path '.' -Recurse | Where-Object {
    if ($_ -is [System.IO.FileInfo]) {
        $directoryName = (Get-Item $_.DirectoryName).Name
        $directoryName -notin $excludeDirs
    } else {
        $true  # Include directories in the results
    }
} |
ForEach-Object {
    if ($_ -is [System.IO.FileInfo]) {
        $oldpath = $_.FullName
        
        # And here is a way to get just the numbers from the filename
        $epNum = [regex]::Replace($_.Name, "[^\d]", "")
        $newName = 'Dragon Ball GT ' + 's01e' + $epNum + '.mkv'
        
        Rename-Item -LiteralPath $oldpath -NewName $newName
        
        $newName
    }
}





# Another one but more complex because the episodes were numbered 1 -... without season restarts
# Define the starting episode of each season at the top

$seasonMapping = @{
    5 = 1
}

# Get all .mkv files in the current directory
$files = Get-ChildItem -Filter *.mkv | Where-Object { $_.PSIsContainer -eq $false }

# Loop through the files and rename them
foreach ($file in $files) {
    # Extract the episode number from the original file name
    if ($file.Name -match " - (\d+)") {
        $fnum = [int]$Matches[1]
        
        # Determine the season based on the mapping
        $season = $seasonMapping.GetEnumerator() | Where-Object { $fnum -ge $_.Value } | Sort-Object Value | Select-Object -Last 1
        $season = $season.Key

        # Calculate the episode number within the season
        $episodeInSeason = $fnum - $seasonMapping[$season] + 1

        # Format the episode number with leading zeros
        $formattedEpisode = "{0:D2}" -f $episodeInSeason

        # Create the new name
        $newName = "Super Dragon Ball Heroes s0$season" + "e$formattedEpisode.mkv"

        # Rename the file
        Rename-Item -LiteralPath $file.FullName -NewName $newName

        $newName
    }
}