Convert value in CSV file

Someone asked me recently how to convert a field value in a CSV file before to process the file with Log Parser. The value in this example is in bytes and needs to be converted to terabytes. The column name that contains this value is ‘BytesColumn’.
Here we go:

$file=Import-Csv "C:\input.csv"
$file | ForEach-Object { $_.BytesColumn=[Math]::Round(($_.BytesColumn/1TB),4,[MidPointRounding]::AwayFromZero) }
$file | Export-Csv "C:\output.csv" -NoTypeInformation