Filtering Operational Mode Command Output

You can redirect the output of operational mode commands into a file or into filters. When you display help about these commands, one of the options listed is | , which is a pipe filter. For example:

Table 7 describes the commands that can be used with the pipe ( | ) option in operational mode.

Table 7: Filtering Operational Mode Command Output

Filter Keyword	Description	See Also
`count`	Displays the number of lines in the output.	Counting the Number of Lines in the Output
`display xml`	Displays the XML content of the command.
`except` `pattern`	Ignores text matching the regular expression. If the regular expression contains spaces, operators, or wildcard characters, enclose it in quotation marks (" " ).	Searching for a String in the Output
`find` `pattern`	Displays output starting at the first occurrence of text matching the regular expression. If the regular expression contains spaces, operators, or wildcard characters, enclose it in quotation marks (" " ).	Searching for a String in the Output
`hold`	Holds text without exiting the -More- prompt.	Retaining the Output After the Last Screen
`last` `lines`	Displays text starting at the specified number of lines from the end of the output.	Displaying the Lines You Want to View from the End of the Output
`match` `pattern`	Searches for text matching the regular expression. If the regular expression contains spaces, operators, or wildcard characters, enclose it in quotation marks.	Searching for a String in the Output
`no-more`	Displays output all at once rather than one screen at a time.	Displaying All Output at Once
`request message` (`all` \| `user` `account@terminal`)	Display command output on the terminal of a specific user logged onto your router, or on the terminals of all users logged onto your router.	Sending Command Output to Other Users
`resolve` [`full-names` \| `truncate`]	Converts IP addresses into domain name server (DNS) names. By default, names are truncated to fit the original size. To prevent names from being truncated, use the full-names keyword.
`save` `filename`	Saves the output to a file.	Placing Command Output in a File
`trim` `columns`	Trims the specified number of columns from the start line.

For the output of a single command, you can redirect the output one or more times. For example:

The following sections provide additional information for most of the pipe ( | ) filter options described in Table 7:

Counting the Number of Lines in the Output

To count the number of lines in the output, specify the count command after the pipe. For example:

Searching for a String in the Output

You can filter the output to search for a text matching a regular expression. You can match a regular expression, match everything except a regular expression, or find the first occurrence of text matching a regular expression. All searches are not case-sensitive.

To ignore text that matches a regular expression, specify the except command after the pipe:

To find the first occurrence of a regular expression, specify the find command after the pipe:

If the regular-expression contains any spaces, operators, or wildcard characters, enclose it in quotation marks.

You use extended regular expressions to specify what text in the output to match. Command regular expressions implement the extended (modern) regular expressions as defined in POSIX 1003.2.

Table 8: Common Regular Expression Operators

Operator	Match...
`\|`	One of the two terms on either side of the pipe.
`^`	At the beginning of an expression, used to denote where the command begins, where there might be some ambiguity.
`$`	Character at the end of a command. Used to denote a command that must be matched exactly up to that point. For example, `allow-commands "show interfaces $"` means that the user cannot issue `show interfaces detail` or `show interfaces extensive`.
`[ ]`	Range of letters or digits. To separate the start and end of a range, use a hyphen ( `-` ).
`( )`	A group of commands, indicating an expression to be evaluated and the result is then evaluated as part of the overall expression.

Display the output, starting not at the beginning but rather at the first occurrence of text matching a regular expression, using the find command after the pipe:

If the regular expression contains spaces, operators, or wildcard characters, enclose the expression in quotation marks.

Retaining the Output After the Last Screen

When you view output one screen at a time, you typically return to the CLI prompt after viewing the last screen.

To not return immediately, use the hold command after the pipe. This feature is useful, for example, when you want to scroll or search through the output.

Displaying the Lines You Want to View from the End of the Output

By default, the last command displays the lines from the end of the output. You can also specify the number of lines to display from the end of the output. If the number of specified lines is less than a screen full, the command will display a screen full of output. This feature is most useful for viewing log files where the end of the files contain the most recent entries.

To view the most recent entries from the end of the output, use the | last command after the pipe:

Displaying All Output at Once

To display the output all at once instead of one screen at a time, specify the no-more command after the pipe. This command is equivalent to the set cli screen-length 0 command, but affects the output of the one command only.

Sending Command Output to Other Users

If you are troubleshooting your router and, for example, talking with a customer service representative on the phone, you can use the request message command to send your representative the command output you are currently viewing on your terminal.

The following example sends the output from the show interfaces command you enter on your terminal to the terminal of the user root@ttyp1:

Placing Command Output in a File

When the output is very long, when you need to store or analyze the output, or when you need to send the output in e-mail, you can redirect the output to a file. Doing this is useful when the output scrolls off the screen, making it difficult to cut the output from a window and paste it into another.

By default, the file is placed in your home directory on the router. For information about how you can specify the filename, see Specifying Filenames and URLs.

This example stores the output of the request support information command in a file: