Cisco IOS software is the embedded software architecture in all Cisco devices and is also the operating system of Cisco Catalyst switches.
The Cisco IOS Software command-line interface (CLI) is used by network administrators to monitor and configure Cisco devices. You access the CLI by establishing a console connection or a Telnet connect connection to the Cisco devices. Log in to the Cisco device brings up a CLI window, where you are put into user EXEC mode by default and the prompt sign is ">". The command exit close the session from the user EXEC mode.
The Cisco IOS software CLI have very handy help features.
- command avialability help: enter the ? (question mark) command at the user EXEC mode or privileged EXEC mode will reveal commands that available at that EXEC level.
- word help: Enter an incomplete command followed by a ? (without any space between) will display a list of available commands that start with the characters that you entered.
- word auto-complete: Enter an incomplete command, then press TAB key will automatically complete the command for you, provide that only one command exists which start with the characters that you entered.
- command syntax help: Enter a command followed by a space then ? will display a list of the available command options supported by the command that you entered.
The following is the CLI help features demonstration on a Cisco 2960-24TT switch:
----------------------------------------------------Demo Start--------------------------------------------------------
Press RETURN to get started!
User Access Verification
Password:
Switch>?
Exec commands:
<1-99> Session number to resume
connect Open a terminal connection
disconnect Disconnect an existing network connection
enable Turn on privileged commands
exit Exit from the EXEC
logout Exit from the EXEC
ping Send echo messages
resume Resume an active network connection
show Show running system information
telnet Open a telnet connection
terminal Set terminal line parameters
traceroute Trace route to destination
Switch>sh?
show
Switch>show ?
cdp CDP information
clock Display the system clock
dtp DTP information
etherchannel EtherChannel information
flash: display information about flash: file system
history Display the session command history
interfaces Interface status and configuration
ip IP information
mac-address-table MAC forwarding table
sessions Information about Telnet connections
tcp Status of TCP connections
terminal Display terminal configuration parameters
users Display information about terminal lines
version System hardware and software status
vlan VTP VLAN status
vtp VTP information
Switch>show ip ?
arp IP ARP table
interface IP interface status and configuration
Switch>show ip interface ? Vlan Catalyst Vlans
brief Brief summary of IP status and configuration
<cr>
Switch>show ip interface
Vlan1 is administratively down, line protocol is down
Internet protocol processing disabled
Switch>enable
Switch#?
Exec commands:
<1-99> Session number to resume
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
logout Exit from the EXEC
more Display the contents of a file
no Disable debugging informations
ping Send echo messages
reload Halt and perform a cold restart
resume Resume an active network connection
setup Run the SETUP command facility
--More--
----------------------------------------------------Demo end--------------------------------------------------------
Note two points.
Firstly, in the following lines:
Switch>show ip interface ? Vlan Catalyst Vlans
brief Brief summary of IP status and configuration
<cr>
where <cr> means press ENTER key.
Secondly,
--More-- means there are more lines to be displayed, press ENTER key to show one line, press SPACE key to show all lines.
