Cisco Routers for the Desperate, 2nd Edition

Integrated Help

"Help" might be too strong a word, but routers offer hints on commands, command syntax, and the features available in the router at that privilege level. Different versions of the Cisco IOS have different features, and it's not easy to identify them all. The simplest way to see what commands are available is to ask the router. Once you've logged in, enter a single question mark at the command prompt.

router# ?
Exec commands:
  <1-99>           Session number to resume
  clear            Reset functions
  clock            Manage the system clock
...

My test router has four full screens of commands available from a single question mark. Many of these commands are completely irrelevant for a router that is providing basic Internet capability; such activities require only ...