How it works...

On the first line, we verify that the Active Directory module for Windows PowerShell is installed, correctly configured, and ready.

On the second line, we use the Get-ADForest cmdlet from the Active Directory module to get the information for the current Active Directory forest. Then, we pipe the output of that command to select only the domains, since that's what we're after.

You can now make the best choices for implementing new domains and/or forests, and/or decommissioning domains and/or forests.