LAB-3
Cisco IOS Command Modes
The Cisco IOS user interface is divided
into many different modes. The commands available to you depend on which mode
you are currently in. Enter a question mark (?) at the system prompt to obtain
a list of commands available for each command mode.
When you start a session on the
wireless device, you begin in user mode, often called user EXEC mode. A
subset of the Cisco IOS commands is available in user EXEC mode. For example,
most of the user EXEC commands are one-time commands, such as show
commands, which show the current configuration status, and clear
commands, which clear counters or interfaces. The user EXEC commands are not
saved when the wireless device reboots.
To have access to all commands, you
must enter privileged EXEC mode. Normally, you must enter a password to enter
privileged EXEC mode. From this mode, you must enter privileged EXEC mode
before you can enter the global configuration mode.
Using the configuration modes (global,
interface, and line), you can make changes to the running configuration. If you
save the configuration, these commands are stored and used when the wireless
device reboots. To access the various configuration modes, you must start at
global configuration mode. From global configuration mode, you can enter
interface configuration mode and line configuration mode.
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Table 4-1
Command Mode Summary
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Mode
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Access
Method
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Prompt
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Exit
Method
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About
This Mode
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User EXEC
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Begin a session with the wireless
device.
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ap> |
Enter logout or quit.
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Use this mode to:
�Change
terminal settings
�Perform
basic tests
�Display
system information
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Privileged EXEC
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While in user EXEC mode, enter the enable
command.
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ap# |
Enter disable to exit.
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Use this mode to verify commands. Use
a password to protect access to this mode.
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Global configuration
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While in privileged EXEC mode, enter
the configure command.
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ap(config)# |
To exit to privileged EXEC mode,
enter exit or end, or press Ctrl-Z.
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Use this mode to configure parameters
that apply to the entire wireless device.
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Interface configuration
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While in global configuration mode,
enter the interface command (with a specific interface).
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ap(config-if)# |
To exit to global configuration mode,
enter exit. To return to privileged EXEC mode, press Ctrl-Z or
enter end.
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Use this mode to configure parameters
for the Ethernet and radio interfaces. The 2.4-GHz radio is radio 0, and the
5-GHz radio is radio 1.
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Getting Help
You can enter a question mark (?) at
the system prompt to display a list of commands available for each command
mode.
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Table 4-2 Help Summary
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Command
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Purpose
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help
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Obtains a brief description of the
help system in any command mode.
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abbreviated-command-entry?
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Obtains a list of commands that begin
with a particular character string.
For example:
ap# di? dir� disable� disconnect |
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abbreviated-command-entry<Tab>
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Completes a partial command name.
For example:
ap# sh conf<tab> ap# show configuration |
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?
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Lists all commands available for a
particular command mode.
For example:
ap> ? |
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command ?
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Lists the associated keywords for a
command.
For example:
ap> show ? |
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command
keyword ?
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Lists the associated arguments for a
keyword.
For example:
ap(config)# cdp holdtime ? � <10-255>� Length of time (in sec) that receiver must keep this packet |
Abbreviating
Commands
You have to enter only enough characters
for the wireless device to recognize the command as unique. This example shows
how to enter the show configuration privileged EXEC command:
ap# show conf
Using
no and default Forms of Commands
Most configuration commands also have a
no form. In general, use the no form to disable a feature or
function or reverse the action of a command. For example, the no shutdown
interface configuration command reverses the shutdown of an interface. Use the
command without the keyword no to re-enable a disabled feature or to
enable a feature that is disabled by default.
Configuration commands can also have a default
form. The default form of a command returns the command setting to its default.
Most commands are disabled by default, so the default form is the same as the no
form. However, some commands are enabled by default and have variables set to
certain default values. In these cases, the default command enables the command
and sets variables to their default values.
Using Command History
The CLI provides a history or record
of commands that you have entered. This feature is particularly useful for
recalling long or complex commands or entries, including access lists. You can
customize the command history feature to suit your needs as described in these sections:
Changing the Command History Buffer Size
By default, the wireless device records
ten command lines in its history buffer. Beginning in privileged EXEC mode,
enter this command to change the number of command lines that the wireless
device records during the current terminal session:
ap# terminal history [size number-of-lines]
The range is from 0 to 256.
Beginning in line configuration mode,
enter this command to configure the number of command lines the wireless device
records for all sessions on a particular line:
ap(config-line)# history [size number-of-lines]
The range is from 0 to 256.
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Table 4-4
Recalling Commands
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Action1
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Result
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Press Ctrl-P or the up arrow
key.
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Recall commands in the history
buffer, beginning with the most recent command. Repeat the key sequence to
recall successively older commands.
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Press Ctrl-N or the down arrow
key.
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Return to more recent commands in the
history buffer after recalling commands with Ctrl-P or the up arrow
key. Repeat the key sequence to recall successively more recent commands.
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show history
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While in privileged EXEC mode, list
the last several commands that you just entered. The number of commands that
are displayed is determined by the setting of the terminal history
global configuration command and history line configuration command.
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Disabling the Command History Feature
The command history feature is
automatically enabled.
To disable the feature during the
current terminal session, enter the terminal no history privileged EXEC
command.
To disable command history for the
line, enter the no history line configuration command.
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Table 4-5 Editing Commands
Through Keystrokes
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Capability
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Keystroke1
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Purpose
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Move around the command line to make
changes or corrections.
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Ctrl-B or the left arrow key
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Move the cursor back one character.
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Ctrl-F or the right arrow key
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Move the cursor forward one
character.
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Ctrl-A
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Move the cursor to the beginning of
the command line.
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Ctrl-E
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Move the cursor to the end of the
command line.
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Esc B
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Move the cursor back one word.
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Esc F
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Move the cursor forward one word.
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Ctrl-T
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Transpose the character to the left
of the cursor with the character located at the cursor.
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Recall commands from the buffer and
paste them in the command line. The wireless device provides a buffer with
the last ten items that you deleted.
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Ctrl-Y
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Recall the most recent entry in the
buffer.
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Esc Y
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Recall the next buffer entry.
The buffer contains only the last 10
items that you have deleted or cut. If you press Esc Y more than ten
times, you cycle to the first buffer entry.
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Delete entries if you make a mistake
or change your mind.
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Delete or Backspace
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Erase the character to the left of
the cursor.
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Ctrl-D
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Delete the character at the cursor.
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Ctrl-K
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Delete all characters from the cursor
to the end of the command line.
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Ctrl-U or Ctrl-X
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Delete all characters from the cursor
to the beginning of the command line.
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Ctrl-W
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Delete the word to the left of the
cursor.
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Esc D
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Delete from the cursor to the end of
the word.
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Capitalize or lowercase words or
capitalize a set of letters.
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Esc C
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Capitalize at the cursor.
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Esc L
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Change the word at the cursor to
lowercase.
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Esc U
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Capitalize letters from the cursor to
the end of the word.
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Designate a particular keystroke as
an executable command, perhaps as a shortcut.
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Ctrl-V or Esc Q
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Scroll down a line or screen on
displays that are longer than the terminal screen can display.
Note The More prompt
appears for output that has more lines than can be displayed on the terminal
screen, including show command output. You can use the Return
and Space bar keystrokes whenever you see the More prompt.
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Return
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Scroll down one line.
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Space
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Scroll down one screen.
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Redisplay the current command line if
the wireless device suddenly sends a message to your screen.
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Ctrl-L or Ctrl-R
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Redisplay the current command line.
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Answer the following questions:
1)
Begin a session
using �User EXEC� mode. What was printed on the screen?
2)
Start a
�privileged EXEC� mode. What was printed on the screen?
3)
Go to �Global
configuration�. While in a global configuration mode, enter the interface mode.
What was printed on the screen?
4)
Exit from global
configuration mode and go to �privilege EXEC� mode and search the following
names: �dir disable disconnect�. What command do you use to print those
names?
5)
In a �privilege
Exec� mode, list the ssh Connection Version Mode Encryption.
6)
Describe the
following error messages: Ambiguous command, incomplete command and Invalid
input detected.
7)
Display the last
16 lines of �terminal history�
8)
Explain the
difference between Privilege Exec and Global Configuration mode.