Help with Host Profiles and PowerCLI needed

Hello,

I have 2 questions on using PowerCLI to edit vSphere Host Profiles:

1) How can I clone a host profile, by using PowerCLI ?

2) How can I modify Host profiles, by using PowerCLI, to update these settings ?
    a) Networking configuration - DNS configuration - Host name
    b) Authentication configuration - Active Directory configuration - Domain Name

Thanks!

Regards,
Harold