convert-srt-to-txt.ps1

$inputFile = '1-he.srt'
$outputFile = '1-he.txt'

# Create a 'memory' of lines we've already processed
$seenLines = New-Object System.Collections.Generic.HashSet[string]

Get-Content $inputFile | Where-Object {
    # 1. Filter out numbers, timestamps, and empty lines
    $_ -notmatch '^\d+$' -and $_ -notmatch '-->' -and $_ -ne ''
} | ForEach-Object {
    $trimmedLine = $_.Trim()
    # 2. Only pass the line forward if we haven't seen it yet
    if ($seenLines.Add($trimmedLine)) {
        $trimmedLine
    }
} | Out-File -FilePath $outputFile -Encoding UTF8