wbadmin get disks
Lists the internal and external disks that are currently online for the local computer.
To list the online disks using this command, you must be a member of the Backup Operators group or the Administrators group, or you must have been delegated the appropriate permissions. In addition, you must run wbadmin from an elevated command prompt, by right-clicking Command Prompt, and then selecting Run as administrator.
Syntax
wbadmin get disks