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To display a brief description of the help system, enter the help command.
helpThis command has no arguments or keywords.
All.
The help command provides a brief description of the context-sensitive help system.
Enter the help command for a brief description of the help system.
Switch# help
Help may be requested at any point in a command by entering
a question mark '?'. If nothing matches, the help list will
be empty and you must backup until entering a '?' show the
available options.
Two styles of help are provided:
1. Full help is available when you are ready to enter a
command argument (e.g. 'show ?') and describes each possible
argument.
2. Partial help is provided when an abbreviated argument is entered
and you want to know what arguments match the input
(e.g. 'show pr?')
The following example shows how to use command syntax help to display the next argument of a partially complete access-list command. One option is to add a wildcard mask. The <cr> symbol indicates that the other option is to press Return to execute the command.
Switch(config)# access-list 99 deny 131.108.134.234 ?
A.B.C.D Mask of bits to ignore
<cr>
To enable the command history function or to change the command history buffer size for a particular line, use the history line configuration command. To disable the command history feature, use the no form of this command.
history [size number-of-lines]| size number-of-lines | (Optional) Specifies the number of command lines that the system records in its history buffer. The range is 0 to 256. |
10 lines.
Line configuration.
The history command without the size keyword and the number-of-lines argument enables the history function with the last buffer size specified or with the default of 10 lines if there was not a prior setting.
The no history command without the size keyword and the number-of lines argument disables the history feature but remembers the buffer size if it was something other than the default. The no history size command resets the buffer size to 10.
The command history feature provides a record of EXEC commands you have entered. This feature is particularly useful for recalling long or complex commands or entries, including access lists.
Table 7-1 lists the keys and functions you can use to recall commands from the command history buffer.
| Key | Function |
|---|---|
| Ctrl-P or Up Arrow1 | Recalls commands in the history buffer in a backward sequence, beginning with the most recent command. Repeat the key sequence to recall successively older commands. |
| Ctrl-N or Down Arrow1 | Returns to more recent commands in the history buffer after recalling commands with Ctrl-P or the Up Arrow. Repeat the key sequence to recall successively more recent commands. |
In the following example, line 4 is configured with a history buffer size of 35 lines.
Switch(config)#line 4Switch(config-line)#history size 35
show history
terminal history size
To specify the hold-queue limit of an interface, use the hold-queue interface configuration command. Use the no form of this command with the appropriate keyword to restore the default values for an interface.
hold-queue length {in | out}| length | Integer that specifies the maximum number of packets in the queue. |
| in | Specifies the input queue. |
| out | Specifies the output queue. |
The default input hold-queue limit is 75 packets. The default output hold-queue limit is 40 packets. These limits prevent a malfunctioning interface from consuming an excessive amount of memory. There is no fixed upper limit to a queue size.
Interface configuration.
This command only applies to the ASP interface. The input hold queue prevents a single interface from flooding the network server with too many input packets. Further input packets are discarded if the interface has too many input packets outstanding in the system.
If priority output queueing is being used, the length of the four output queues is set using the priority-list global configuration command. The hold-queue command cannot be used to set an output hold queue length in this situation.
For slow interfaces, use a small output hold-queue limit. This approach prevents storing packets at a rate that exceeds the transmission capability of the interface. For fast interfaces, use a large output hold-queue limit. A fast interface may be busy for a short time (and thus require the hold queue) but can empty the output hold queue quickly when capacity returns.
To display the current hold queue setting and the number of packets discarded because of hold queue overflows, use the EXEC command show interface.
The following example illustrates how to set a small input queue on a slow async line.
Switch#interface async 0Switch(config-if)#hold-queue 30 in
To specify or modify the host name for the switch, use the hostname global configuration command. The host name is used in prompts and default configuration filenames.
hostname name| name | New host name for the switch; the name is case sensitive. |
The factory-assigned default host name is switch.
Global configuration.
The order of display at startup is banner message-of-the-day (MOTD), then login and password prompts, then EXEC banner.
The following example changes the host name to ls1010.
Switch# hostname ls1010
ls1010#
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