Powershell : Adding users from pre-existing group into "new" group

This is a quick post that enables you to add group members from a pre-existing group to a newly created group, this is a "one liner" for least administrative effort.

Get-ADGroupMember -Identity "<preexisting_group>" | ForEach-Object {Add-ADGroupMember -Identity "<new_group>" -Members $_.distinguishedName}

In this it real world would look something like this:

Get-ADGroupMember -Identity "BearBasic" | ForEach-Object {Add-ADGroupMember -Identity "BearGuests" -Members $_.distinguishedName}

The command above would add all the people from "BearBasic" to "BearGuests" however this can be used a group of any size, however when this command has completed, remember it may take a few seconds for replication, this also is a good place to list other "operational" commands:

Export AD group members to CSV

Get-ADGroupMember -Identity "GroupName" | Select-Object name,samAccountName,distinguishedName | Export-CSV -Path "C:\GroupMembers.csv" -NoTypeInformation

Compare members between two groups:

Compare-Object -ReferenceObject (Get-ADGroupMember -Identity "Group1" | Select-Object -ExpandProperty distinguishedName) -DifferenceObject (Get-ADGroupMember -Identity "Group2" | Select-Object -ExpandProperty distinguishedName)

Add members who are in one group but not in another

Get-ADGroupMember -Identity "SourceGroup" | Where-Object {-not (Get-ADGroupMember -Identity "TargetGroup" | Select-Object -ExpandProperty distinguishedName).Contains($_.distinguishedName)} | ForEach-Object {Add-ADGroupMember -Identity "TargetGroup" -Members $_.distinguishedName}

Remove all members from a group

Get-ADGroupMember -Identity "GroupName" | ForEach-Object {Remove-ADGroupMember -Identity "GroupName" -Members $_.distinguishedName -Confirm:$false}

Copy group memberships from one user to another

Get-ADUser -Identity "SourceUser" -Properties MemberOf | Select-Object -ExpandProperty MemberOf | ForEach-Object {Add-ADGroupMember -Identity $_ -Members "TargetUser"}

Find users who are members of both groups

(Get-ADGroupMember -Identity "Group1").distinguishedName | Where-Object {(Get-ADGroupMember -Identity "Group2").distinguishedName -contains $_} | ForEach-Object {Get-ADUser -Identity $_}

Add users matching specific criteria to a group

Get-ADUser -Filter "Department -eq 'IT' -and Enabled -eq 'True'" | ForEach-Object {Add-ADGroupMember