When we work strictly from Windows Server Core installations we need to be able to do everything from the command line, even user management. Let's add a user that already exists into a group that already exists in Active Directory using only PowerShell.
To do this we have the handy Add-ADGroupMember PowerShell commandlet. This is very easy to use in its basic form, all we need is the name of the group and of the user that we want to add. In this case, I want to add user jane to the group "Domain Admins".Add-ADGroupMember "Domain Admins" jane
That's it, jane is added automatically. This process, like most, is silent on success. To verify that all is as we want it to be, we can use the Get-ADGroupMember command to look up the members of a group.Get-ADGroupMember "Domain Admins"
Can also do
Add-ADGroupMember -identity "Domain Admins" -members "jane" -WhatIf
to see if it gets added before actually running the command.