3com / hp switch commands

Find what port a mac address is learned on
display mac-address 0860-6EE5-DFBD

Show all mac addresses learned on a port
display mac-address interface GigabitEthernet 1/0/9

Show connected switches like show cdp on cisco
display ndp
display ndp interface GigabitEthernet 1/0/9

Disable paging (5500)
user-interface vty 0 4
screen-length 0

Display what interfaces are up/down
display brief interfaces

Show the IP address on the VLAN interfaces
display ip interface brief

Create SVI interface

interface vlan-interface 10

ip address etc

Create loopback interface

interface loopback 1

ip address etc

Show running config
display current-configuration

Enable mode
system-view (sometimes you need to type super first)

Show stp status
display stp brief

Show saved config (in case of switch reboot with blank cfg)
display saved-config
display startup

List files on disk
dir (not in expert mode)