Allied Telesis AT-9000 Series - Manual (Page 78)

Chapter 3: Basic Command Line Management
50
Clearing the Screen
If your screen becomes cluttered with commands, you can start fresh by
entering the CLEAR SCREEN command in the User Exec or Privileged
Exec mode. If you are in a lower mode, you have to move up the mode
hierarchy to one of these modes to use the command. Here is an example
of the command from the Port Interface mode:
awplus(config-if)# end
awplus# clear screen