Getting Online Help from the JUNOS Command-Line Interface

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Getting Online Help from the JUNOS Command-Line Interface

The JUNOS command-line interface (CLI) has a context-sensitive online help feature that enables you to access information about commands and statements from the JUNOS CLI. This topic contains the following sections:

Getting Help About Commands

Information about commands is provided at each level of the CLI command hierarchy. You can type a question mark to get 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, type a question mark (?) at the command-line prompt.
user@host> ?

Possible completions:
clear       Clear information in the system
configure   Manipulate software configuration information
file        Perform file operations
help        Provide help information
mtrace      Trace mtrace packets from source to receiver.
monitor     Real-time debugging
ping        Ping a remote target
quit        Exit the management session
request     Make system-level requests
restart     Restart a software process
set         Set CLI properties, date, time, craft display text
show        Show information about the system
ssh         Open a secure shell to another host
start       Start a software process
telnet      Telnet to another host
test        Diagnostic debugging commands
traceroute  Trace the route to a remote host
user@host>

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 redisplays the command names and options that you typed.
user@host> clear ?

Possible completions:
arp 	      Clear address-resolution information
bgp          Clear BGP information
chassis      Clear chassis information
firewall     Clear firewall counters
igmp         Clear IGMP information
interfaces   Clear interface information
ilmi         Clear ILMI statistics information
isis         Clear IS-IS information
ldp          Clear LDP information
log          Clear contents of a log file
mpls         Clear MPLS information
msdp         Clear MSDP information
multicast    Clear Multicast information
ospf         Clear OSPF information
pim          Clear PIM information
rip          Clear RIP information
route        Clear routing table information
rsvp         Clear RSVP information
snmp         Clear SNMP information
system       Clear system status
vrrp         Clear VRRP statistics information
user@host> clear

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 redisplays the letters that you typed. For example, to list all operational mode commands that start with the letter c, type the following:
user@host> c?
```
Possible completions:
clear      Clear information in the system
configure  Manipulate software configuration information
user@host> c
```
For introductory information on using the question mark or the help command, you can also type help and press Enter:
user@host> help

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:




help apropos string

string is a text string about which you want to get help. This string is used 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.

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:




help topic word


help reference statement-name

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

Getting Help About System Log Messages

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




help syslog syslog-tag

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