Add Users to AD Group Using First Initial

Today at work we had a need to add users to specific Active Directory groups based on the first letter of the first name. We'll be using a plain text file as an example for the list of Active Directory identities. Save the following text into a file called names.txt:

John.Doe
Jane.Doe
Jane.Smith

Then you will need to run this in the PowerShell ISE.

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38

Import-Module ActiveDirectory   # Each row of the text file will be consider one object. The object being the Active Directory identity (SamAccountName). $names = Get-Content c:\names.txt   # Set this to $false when you are ready to make the changes. $whatIf = $true   foreach ($name in $names) {     $user = Get-ADUser -Filter { SamAccountName -eq $name } -Properties MemberOf     if($user) {         # The groups object will contain a list of Active Directory groups by their distinguished name.         # (i.e. CN=GroupName_A-C,OU=Groups,OU=Company,DC=pri,DC=company,DC=com)         $groups = $user | Select-Object -ExpandProperty MemberOf         if(-not ($groups -like 'CN=GroupName_*')) {             $groupName = ''             switch -Regex($user.SamAccountName[0]) {                 # Match the first letter as a, b, or c.                 "[a-c]" { $groupName = 'GroupName_A-C' }                 # Match the first letter as d, e, f, or g.                 "[d-g]" { $groupName = 'GroupName_D-G' }                 "[h-k]" { $groupName = 'GroupName_H-K' }                 "[l-q]" { $groupName = 'GroupName_L-Q' }                 "[r-t]" { $groupName = 'GroupName_R-T' }                 "[u-z]" { $groupName = 'GroupName_U-Z' }             }               if($groupName) {                 "Adding $($user.SamAccountName) to the group $($groupName)"                 Add-ADGroupMember -Identity $groupName -Members $user.SamAccountName -WhatIf:$whatIf             }         } else {             "Skipping $($user.SamAccountName) because they are already in the group $($groupName)"         }     } else {         "$($name) does not exist"     } }