large-file-replace.ps1

# Replace commas by dots in a very large file (full streaming)
$infile = ls .\MyFile.csv
$outfile = $infile.DirectoryName + "\MyFile.csv.out"
$reader = [System.IO.File]::OpenText($infile.FullName)
$writer = [System.IO.StreamWriter] $outfile
try {
  for(;;) {
    $line = $reader.ReadLine()
    if ($line -eq $null) { break }
    # process the line
    $writer.WriteLine($line.Replace(",","."))
  }
}
finally {
  $reader.Close()
  $writer.Close()
}