Quick function to rename subtitle files for Plex subtitle cleanup jobs to remove duplicate locale's. Assumes you are only using a single locale for subs. Defaults to English and SRT extension.

Rename-Subtitles

function Rename-Subtitles {
    [CmdletBinding()]
    Param
    (
        [parameter(Mandatory = $true,Position = 0,ValueFromPipeline = $true)]
        [ValidateScript({Test-Path $_})]
        [String]
        $Path,
        [parameter(Mandatory = $false)]
        [String]
        $Locale = "en",
        [parameter(Mandatory = $false)]
        [String]
        $Extension = "srt"
    )
    Process {
        foreach ($P in $Path) {
            $subs = Get-ChildItem $P -Recurse | Where-Object {$_.Name -like "*.$($Extension)"}
            foreach ($sub in $subs) {
                $clearName = ((($sub.Name -replace "\.$($Locale)\.",".") -replace "\.$($Locale)\.",".") -replace "\.$($Locale)\.",".") -replace "\.$($Extension)$",".$($Locale).$($Extension)"
                Write-Host -ForegroundColor Yellow "Renaming '$($sub.FullName)' to '$($sub.Directory)\$($clearName)'"
                Rename-Item -Path $sub.FullName -NewName $clearName -Force
            }
        }
    }
}

Tip Time

Place this in your PowerShell $PROFILE for ease of use by doing the following:

1. Open your PowerShell profile by running ise $profile. If you get an error that the file doesn't exist, run "" > $profile to create it then re-run ise $profile
2. Copy the function in the Gist and paste it in your profile once it opens in PowerShell ISE, then save.
3. Close PowerShell ISE and your first PowerShell window.

Once you do the above, the function will be available in session whenever you open PowerShell.

Usage

Run the following, replacing the fake path "C:\Media Library" with the actual path to the folder containing your media:

Rename-Subtitles -Path "C:\Media Library"

You should see output similar to the following showing you all the files it's renaming:

Renaming 'E:\SubsTest\noEn.srt' to 'E:\SubsTest\noEn.en.srt'
Renaming 'E:\SubsTest\oneEn.en.srt' to 'E:\SubsTest\oneEn.en.srt'
Renaming 'E:\SubsTest\threeEn.en.en.en.srt' to 'E:\SubsTest\threeEn.en.srt'
Renaming 'E:\SubsTest\twoEn.en.en.srt' to 'E:\SubsTest\twoEn.en.srt'
Renaming 'E:\SubsTest\subfolder\noEn.srt' to 'E:\SubsTest\subfolder\noEn.en.srt'
Renaming 'E:\SubsTest\subfolder\oneEn.en.srt' to 'E:\SubsTest\subfolder\oneEn.en.srt'
Renaming 'E:\SubsTest\subfolder\threeEn.en.en.en.srt' to 'E:\SubsTest\subfolder\threeEn.en.srt'
Renaming 'E:\SubsTest\subfolder\twoEn.en.en.srt' to 'E:\SubsTest\subfolder\twoEn.en.srt'