PowerShell – ForEach do action X or do Y

PowerShell is one of the greatest tools within any IT Professional toolkit, it enables you to do far more than any GUI available to you today. In my life as a Consultant for a Global Microsoft SI (System Integrator), I face challenges every day where PowerShell has come to the rescue. One of the best cmdlet I use in a lot of script is

ForEach which is the alias name of ForEach-Object

Imagine you need to modify an ExtensionAttribute for your entire organization or grant a permission to a subset of users, ask yourself this? How would I do this in a GUI? and the answer would be “with great difficulty or very time consuming”. This is Foreach-Object comes into play, in the below example I need to modify the PrimarySMTPAddress due to special characters being used


In order to correct this, I will be using a source CSV file which contains SamAccountName for the identity of each DistributionList and the correct PrimarySMTPAddress.

Source CSV file

Now for the most important element, the powershell script which will be used to modify the PrimarySMTPAddress. The below script has been designed to achieve the required outcome but also includes the ability to;

  • Be ran using native PowerShell for On-Premises Exchange Servers (2007 through to 2019)
  • Be ran against Exchange Online

So as we can see the Foreach command is being used in the following;

  • For each $row within the $csv which is being imported try and get the distribution list using the column heading SamAccountName
    • If the Identity cannot be found the script will move to the catch
    • If the Identity can be found the script will set the distribution list using the column heading PrimarySMTPAddress
  • The catch is alert if there are any unsuccessful attempts at setting the PrimarySMTPAddress


$file = "$env:USERPROFILE\OneDrive\Desktop\groups.csv"
$csv = import-csv -Path $file
region Exchange Module SnapIn
# Exchange 2007
#Add-PSSnapin Microsoft.Exchange.Management.PowerShell.Admin;
# Exchange 2010
#Add-PSSnapin Microsoft.Exchange.Management.PowerShell.E2010;
# Exchange 2013/2016
#Add-PSSnapin Microsoft.Exchange.Management.PowerShell.SnapIn;
Start-Transcript -Path $env:USERPROFILE\OneDrive\Desktop\Get-DistributionGroup.txt
Foreach ($row in $csv)
try {
Get-DistributionGroup -Identity $row.SamAccountName | Set-DistributionGroup -PrimarySmtpAddress $row.PrimarySmtpAddress
Write-Host 'INFO:' ($row.SamAccountName),'Primary SMTP Address has now been modified to',($row.PrimarySmtpAddress) -BackgroundColor Green
Write-Host 'ERROR:' ($row.SamAccountName),'Primary SMTP Address has not been modified to',($row.PrimarySmtpAddress) -BackgroundColor Red
Image result for meerkat simples gif

I have included Start-Transcript as this will dump out all Write-Host entry whether they was successful or not.


The Author – Blogabout.Cloud