Add column CSV in existing CSV with powershell

Question

I have a Powershell script, which collects the size of a backup, and exports it to CSV, I would like to know if it is possible that it could be added to the next csv column, or an excel.

I've been looking at the documentation, because I think it looks better on an excel, but I can't add one more column, I always believe it from scratch.

$today = (get-date).Date
$backup = Get-VBRBackup | where {$_.info.jobname -eq "A. ProduccionInterna.Infraestructura Backup Copy"}
if ($backup) {
$backup.GetAllStorages() | where {$_.CreationTime.Date -eq $today} | select {$_.PartialPath}, {$_.Stats.BackupSize/1GB} |
export-csv -Path C:\Users\acepero\Documents\test.csv -NoTypeInformation -Delimiter ';'
}

UPDATE

I have managed to create new columns once, then it gives an error:

Select-Object : The property cannot be processed because the property "{$_.PartialPath}, {$_.Stats.BackupSize/1GB} , {$Session.BackupStats.DedupRatio} , 
{$Session.BackupStats.CompressRatio}" already exists.

The code now has this form

$today = (get-date).Date
$backup = Get-VBRBackup | where {$_.info.jobname -eq "A. ProduccionInterna.Infraestructura Backup Copy"}
if ($backup) {
$backup.GetAllStorages() | where {$_.CreationTime.Date -eq $today} | select {$_.PartialPath}, {$_.Stats.BackupSize/1GB} , {$Session.BackupStats.DedupRatio} , {$Session.BackupStats.CompressRatio} 
(Import-Csv "C:\Users\acepero\Documents\test.csv") |
    Select-Object *, {{$_.PartialPath}, {$_.Stats.BackupSize/1GB} , {$Session.BackupStats.DedupRatio} , {$Session.BackupStats.CompressRatio}} |
Export-csv -Path C:\Users\acepero\Documents\test.csv -NoTypeInformation #-Delimiter ';' 
}

Answer 1

When you take output from a command and pipe it through select, you are creating an output object, which has the selected values as properties. Here is an example using the Get-ChildItem command:

$result = Get-ChildItem C:\Temp | select Name, Length

The $result array contains objects which have the "Length" and "Name" NoteProperties. When you pipe that object to Export-CSV, it creates one column for each Property/NoteProperty the object has. In order to 'add a column to the CSV', all you need to do is add a NoteProperty to the object. You can do that with the Add-Member cmdlet, like this:

$result | Add-Member -MemberType NoteProperty -Name 'ColumnName' -Value 'ColumnValue'

Be careful how you do this. If $result is a single object, this command will add the NoteProperty/Value pair to that object. If $result is an array of objects, it will add that NoteProperty/Value pair to all objects held in the array. If you need to assign different values to each object, you'll need to iterate through the array:

ForEach ($res in $result)
{
    $thisvalue = '' #Assign specific value here
    $res | Add-Member -MemberType NoteProperty -Name 'ColumnName' -Value $thisvalue
}

I hope this helps you. If it does, please don't forget to accept the answer.