[Roddy Gelberty]

Get-WmiObject -Class Win32_ComputerSystem|Select-Object -Property *

You can run the above command for the win32_computersystem class. Other classes might require you to expose the extended properties by using the -Properties switch.

$param = @("displayname", "givenname", "sn", "manager", "mail","streetaddress", "city", "st", "postalcode","co","telephonenumber", 
"mobile", "ipphone", "homephone","extensionattribute2", "extensionattribute3", "extensionattribute4","company", "department",
"extensionattribute1", "title", "physicaldeliveryofficename")

get-aduser -filter * -properties $param | Select-Object $param