General commands

sh ip traffic – all traffic through the Cisco
sh controllers ethernet-controller gi1/0/1 phy – information about the SFP module into a particular port
show vlan internal usage – used to show vlan
sh inventory raw – in 4924 about stuck SFP seems to be the only way to see.
sh ip protocols – all of the dynamic routing

Tracing

traceroute mac aaaa.bbbb.cccc dddd.eeee.ffff (Traces source and destination mac addresses over multiple switches)

sh platform …
sh platform tcam utilization – a place in the TCAM Diagnosing problems with the fallback interface / memory / CPU
sh controllers cpu-interface
sh controllers utilization – the percentage loading of interfaces. Plus upload the switch factory
sh controllers tcam sh controllers tcam asic
sh controllers ethernet-controller phy
sh controllers ethernet-controller port-asic statistics
sh controllers ethernet-controller port-asic configuration
sh controllers ethernet-controller gigabitEthernet 1/0/1

show interfaces counters protocol status
show interfaces summary
show interfaces accounting
sh interfaces stats – statistics on the interface, the method of switching
sh interfaces switching – a hidden command. More detail than the stats.
sh interface switchport – diagnostic vlan
show interface trunk – for the diagnosis of vlan
show int | i proto.*notconnect|proto.*administratively down|Last in.* [6-9]w|Last in.*[0-9][0-9]w|[0-9]y|disabled|Last input never, output never, output hang never