- The Cisco IOS—Basic Router Commands
- Log In on the Console
- Entering the Privileged Mode
- Router Mode Summary
- The IOS Help Facility
- Command History and Editing Features
- The show Command
- Router Memory Types
- Examining RAM, NVRAM, and Flash RAM
- The Cisco Discovery Protocol
- More About show
- Objective 11: Telnet
- Help System
The IOS Help Facility
No matter which mode you're in, the Cisco IOS can provide you with help. You can view a list of commands available in a particular mode, or you can get context-sensitive help related to a particular command. For a brief description of how the help system works, type help or ? at any prompt, and then press Enter.
For example, let's say that you are in the user mode and want to see a complete list of the commands available. Type ?, and then press Enter. The commands are listed on the console screen shown in the following figure.
The commands listed by the ? command will depend on the IOS version with which you are working. You should become familiar with IOS version 11.3 for the CCNA exam. To see your IOS version, use the command show ver.
You can get context-sensitive help for any command by typing the command and following it with a ?. For example, to see the list of uses for the show command, type show ?. You will be provided with help specifically for the show command (see the following figure).
After the help for the specific command is listed, you are returned to the router prompt with the command already entered. All you have to do is enter other necessary parameters (listed in the context-sensitive help) to complete the command. Next, press Enter to enter the command after providing the additional parameters.
You can also get a list of commands that start with a particular letter or abbreviation. Type the letter or abbreviation at the prompt immediately followed by a ?, and then press Enter. For example, typing s? at the user prompt provides a list of the commands show, slip, set, and systat (all the commands that start with the letter s). To get additional help on these commands, type the complete command and follow it with a question mark.
When the information provided by a particular command, such as ?, doesn't fit on one console screen, More appears at the bottom of the displayed information. To move down through the additional information, press Enter to advance one line and press the spacebar to advance one screen. If you don't want to view more information and want to return to the console prompt, press Esc.