It is not common see a Cisco crash: Software forced crash, Bus Error, Software watchdog timeout, and so on… But if you would do it, there is a pretty trick : it’s the “test crash” command, an hidden IOS command. This can help you if you are lucky enough to have the real crash exactly like one of those you can test with “test crash” command.

Surfing the web, I have found a document concerning the undocumented cisco commands. The document is write by Lars Fenneberg (CCIE #7325) and it’s quite old (last revision in 2005). Certainly this is not a complete list, but I suppose that could be funny to discover some new commands… I have tried to found other document more exhaustive with no result.