Online Help in the CLI

Getting Help About Commands

CLI commands and options can vary by platform and software release. Each level of the CLI command hierarchy provides information about available commands. You can type a question mark (?) to get context-relevant help about commands.

• If you type the question mark at the command-line prompt, the CLI lists the available commands and options. For example, to view a list of top-level operational mode commands, this is the result:

• If you type the question mark after entering the complete name of a command or command option, the CLI lists the available commands and options and then re-displays the command names and options you typed.

• If you type the question mark in the middle of a command name, the CLI lists possible command completions that match the letters you have entered so far. It then re-displays the letters that you typed. For example, to list all operational mode commands that start with the letter c, type the following:

• For introductory information on using the question mark or the help command, you can also type help and press Enter:

Getting Help About a String in a Statement or Command

You can use the help command to display help about a text string contained in a statement or command name:

string is a text string about which you want to get help. Use the string to match statement or command names as well as to match the help strings that are displayed for the statements or commands.

If the string contains spaces, enclose it in quotation marks (" "). You can also specify a regular expression for the string, using standard UNIX-style regular expression syntax.

For statements or commands that need input data type as STRING, the supported characters set is as follows:

• Any printable ASCII characters

• For characters with space, enclose it in double-quotes.

• To have double-quote as the input, it should be escaped with ‘\’.

  Note:

  No escape characters are supported in a string other than to escape from double quotes.

• The range of supported characters for attributes is 0 through 65499 characters.

• The range of supported characters for string type identifiers is 1 through 255 characters.

In configuration mode, this command displays statement names and help text that match the string specified. In operational mode, this command displays command names and help text that match the string specified.

Getting Help About Configuration Statements

You can display help based on text contained in a statement name using the help topic and help reference commands:

The help topic command displays usage guidelines for the statement based on information that appears in the Junos OS configuration guides. The help reference command displays summary information about the statement based on the summary descriptions that appear in the Junos OS configuration guides.

Getting Help About System Log Messages

You can display help based on a system log tag using the help syslog command:

The help syslog command displays the contents of a system log message.

Help for Omitted Statements

If you have omitted a required statement at a specific hierarchy level, when you attempt to move from that hierarchy level or when you issue the show command in configuration mode, a message indicates which statement is missing. For example:

 

Using CLI Command Completion

The Junos OS CLI provides you a command completion option that enables the operating system to recognize commands and options based on the initial few letters you typed. That is, you do not always have to remember or type the full command or option name for the CLI to recognize it.

• To display all possible command or option completions, type the partial command followed immediately by a question mark.

• To complete a command or option that you have partially typed, press Tab or Space. If the partially typed letters begin a string that uniquely identifies a command, the complete command name appears. Otherwise, a prompt indicates that you have entered an ambiguous command, and the possible completions display.

Command completion also applies to other strings, such as filenames, interface names, and usernames. To display all possible values, type a partial string followed immediately by a question mark. To complete a string, press Tab.

Using Command Completion in Configuration Mode

The CLI command completion functions also apply to the commands in configuration mode and to configuration statements. Specifically, to display all possible commands or statements, type the partial string followed immediately by a question mark. To complete a command or statement that you have partially typed, press Tab or Space.

Displaying Tips About CLI Commands

To get tips about CLI commands, issue the help tip cli command. Each time you enter the command, a new tip appears. For example:

You can also enter help tip cli number to associate a tip with a number. This enables you to recall the tip later. For example: