Question: How can I obtain a list of BUILTIN\Administrators members using Powershell ?
Answer: There is a Powershell cmdlet Get-LocalGroupMember. This cmdlet will give you a basic listing , it is then possible to perform a range of data manipulations according to your requirements . Here are some examples
--Example1 : get all members of the Server Local Administrators group
Get-LocalGroupMember -Group "Administrators"
--Example 2: get all members of a Server Local Administrators group on a Remote server, get-localgroupmember doesn't currently support -computer switch
Invoke-Command -ComputerName [computer] -ScriptBlock {Get-LocalGroupMember -Name "Administrators"}
--Example 3: get all members of the Server Local Administrator Group , including SID & Object Class
Get-LocalGroupMember -Group "Administrators" | Select-Object *
--Example 4: get all members of the Server Local Administrator Group ,sort by Name
Get-LocalGroupMember -Group "Administrators" | Sort-Object Name
--Example 5 : get or check members from the Server Local Administrator Group , where a specific member exists.Using Powershell Where-Object
Invoke-Command -ComputerName MyServer1 -ScriptBlock {Get-LocalGroupMember -Group "Administrators" | Select-Object Name | Where-Object {$_.Name -eq 'MYDOMAIN\my_ad_Group'}}
More reading on Powershell & Users
How to extract Active Directory users with Get-ADGroup and Get-ADGroupMember
How to find Active Directory users with Get-ADUser search filter
How to list Windows users with Powershell