The most wonderful thing about Cisco’s IOS command line interface is that help is available every step of the way. There are a few tricks to using the help system effectively. The most basic element that you’ll need to be familiar with is the help command itself – the question mark.
From the command line, you can always get information on available commands by entering ?. This command is sensitive to where you happen to be in the environment – for example, the commands that are available to you from user mode are different than those available in privileged mode, which in turn are different from those available when configuring an interface. We’ll look at configuration modes shortly. For now, we’ll start off by getting a sense of how to use the help command effectively.
Notice that when we press ? from privileged mode, we’re presented with a list of available 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
bfe For manual emergency modes setting
cd Change current directory
clear Reset functions
clock Manage the system clock
configure Enter configuration mode
connect Open a terminal connection
copy Copy from one file to another
debug Debugging functions (see also 'undebug')
delete Delete a file
dir List files on a filesystem
disable Turn off privileged commands
disconnect Disconnect an existing network connection
enable Turn on privileged commands
erase Erase a filesystem
exit Exit from the EXEC
help Description of the interactive help system
lock Lock the terminal
login Log in as a particular user
The list displayed only includes commands up to login – this is a function of my screen display size. Can you see the –More– entry at the bottom of the list? You can display the remaining commands, one screen at a time, by pressing the spacebar. You can also view additional commands one at a time by pressing the Enter key. Each command also provides a short explanation of what it is used for.