Sep.16, 2010, under Networks
This is going to be a series of short posts on little features in IOS which make your life easier. These won’t change your life or anything, but knowing them will make you much more proficient when sitting at a console. The first feature I’m going to discuss I hope everyone is aware of, the command lookup. This is incredibly useful when you can’t quite remember what command you need and it can be used in two slightly different ways.
The first way is when you have no clue at all what you need to type, and just want a refresher of what options are available. Typing the ‘?’ character will show you all possible commands with a brief description, eg
Router#? Exec commands: <1-99> Session number to resume access-enable Create a temporary Access-List entry access-profile Apply user-profile to interface access-template Create a temporary Access-List entry archive manage archive files audio-prompt load ivr prompt auto Exec level Automation beep Blocks Extensible Exchange Protocol commands bfe For manual emergency modes setting calendar Manage the hardware calendar call Voice call ccm-manager Call Manager Application exec commands cd Change current directory cellular cellular commands clear Reset functions clock Manage the system clock cns CNS agents configure Enter configuration mode connect Open a terminal connection copy Copy from one file to another credential load the credential info from file system crypto Encryption related commands. --More--
Press space to see more. You can also use this on a nested basis, eg
Router#show access-lists ? <1-2799> ACL number WORD ACL name compiled Compiled access-list statistics rate-limit Show rate-limit access lists | Output modifiers <cr> Router#show access-lists
The second, slightly different way to use this is when halfway through a command, it will try and match based on what you have already typed
Router#show ip in? inspect interface Router#show ip i? icmp igmp inspect interface ips irdp Router#show ip in? inspect interface Router#show ip in
However note that in this case you don’t get the command descriptions.
You can use this from any mode, so it works in config, user exec, privileged exec. A lot of the commands you’ll come to learn by heart, but this is very useful for the ones you use less often.