Ch. 4: Using the Command-Line Interface Flashcards
Command-line interface
An interface that enables the user to interact with the operating system by entering commands and optional arguments.
Telnet
The standard terminal-emulation application layer protocol in the TCP/IP protocol stack. Telnet is used for remote terminal connection, enabling users to log in to remote systems and use resources as if they were connected to a local system. Telnet is defined in RFC 854.
Secure Shell (SSH)
A TCP/IP application layer protocol that supports terminal emulation between a client and server, using dynamic key exchange and encryption to keep the communications private.
enable mode
A part of the Cisco IOS CLI in which the user can use the most powerful and potentially disruptive commands on a router or switch, including the ability to then reach configuration mode and reconfigure the router.
user mode
A mode of the user interface to a router or switch in which the user can type only nondisruptive EXEC commands, generally just to look at the current status, but not to change any operational settings.
configuration mode
A part of the Cisco IOS Software CLI in which the user can type configuration commands that are then added to the device’s currently used configuration file (running-config).
startup-config file
In Cisco IOS switches and routers, the name of the file that resides in NVRAM memory, holding the device’s configuration that will be loaded into RAM as the running-config file when the device is next reloaded or powered on.
running-config file
In Cisco IOS switches and routers, the name of the file that resides in RAM, holding the device’s currently used configuration.
line console 0
Global command that changes the context to console configuration mode.
login
Line (console and vty) configuration mode. Tells IOS to prompt for a password (no username).
password (pass-value)
Line (console and vty) configuration mode. Sets the password required on that line for login if the login command (with no other parameters) is also configured.
interface (type port-number)
Global command that changes the context to interface mode—for example, interface FastEthernet 0/1.
hostname (name)
Global command that sets this switch’s hostname, which is also used as the first part of the switch’s command prompt.
exit
Moves back to the next higher mode in configuration mode.
end
Exits configuration mode and goes back to enable mode from any of the configuration submodes.
Ctrl+Z
This is not a command, but rather a two-key combination that together do the same thing as the end command.
no debug all / undebug all
Enable mode EXEC command to disable all currently enabled debugs.
reload
Enable mode EXEC command that reboots the switch or router.
copy running-config startup-config
Enable mode EXEC command that saves the active config, replacing the startup-config file used when the switch initializes.
copy startup-config running-config
Enable mode EXEC command that merges the startup-config file with the currently active config file in RAM.
show running-config
Lists the contents of the running-config file.
write erase
erase startup-config
erase nvram:
These enable mode EXEC commands erase the startup-config file.
quit
EXEC command that disconnects the user from the CLI session.
show startup-config
Lists the contents of the startup-config (initial config) file.
enable
Moves the user from user mode to enable (privileged) mode and prompts for a password if one is configured.
disable
Moves the user from enable mode to user mode.
configure terminal
Enable mode command that moves the user into configuration mode.
