Arp / Dos command format output

Hi

Im looking to run the arp command within powershell and format the output so I only see the mac addresses

Ive been trying for a while and gotten as far as         arp -A | sort-object "Physical Address"

alternatively is the a powershell equivelent of arp?  Ive tried Get-Macaddress but tht dosent work.

Generally how do I choose which column info I want from a dos command?

Anyone?

Thanks for reading

confuseis