Using the Command-Line Interface

This section contains the following topics:

• CLI Command Hierarchy
• Starting the CLI
• CLI Operational Mode
• CLI Configuration Mode
• CLI Basics

For more information about the CLI, see the Junos CLI User Guide.

CLI Command Hierarchy

The CLI commands are organized hierarchically, with commands that perform a similar function grouped together under the same level. For example, all commands that display information about the device system and system software are grouped under the show command, and all commands that display information about the routing table are grouped under the show route command. Figure 1 illustrates a portion of the show command hierarchy.

To execute a command, you enter the full command name, starting at the top level of the hierarchy. For example, to display a brief view of the routes in the routing table, use the command show route brief.

The hierarchical organization results in commands that have a regular syntax and provides the following features that simplify CLI use:

• Consistent command names—Commands that provide the same type of function have the same name, regardless of the portion of the software they are operating on. For example, all show commands display software information and statistics, and all clear commands erase various types of system information.
• Lists and short descriptions of available commands—Information about available commands is provided at each level of the CLI command hierarchy. If you type a question mark (?) at any level, you see a list of the available commands along with a short description of each command.
• Command completion—Command completion for command names (keywords) and command options is also available at each level of the hierarchy. If you type a partial command name followed immediately by a question mark (with no intervening space), you see a list of commands that match the partial name you typed.

Starting the CLI

To start the CLI:

1. Establish a connection with the device:
   • To access the device remotely from the network, enter the command you typically use to establish a remote connection (such as Telnet or ssh) using the device hostname.
   • To access the device through a management device attached to the console port, start the terminal application.
   • To access the device through the J-Web interface, select Troubleshoot>CLI Terminal in the J-Web interface. For more information, see the J-Web Interface User Guide.
2. Log in using your username and password.

   After you log in, you enter a UNIX shell.

3. Start the CLI.
   % cliuser@host>

The presence of the angle bracket (>) prompt indicates the CLI has started. By default, the prompt is preceded by a string that contains your username and the hostname of the router.

To exit the CLI and return to the UNIX shell, enter the quit command.

CLI Operational Mode

The CLI has two modes: operational and configuration. When you log in to the device and the CLI starts, you are at the top level of operational mode.

To view a list of top-level operational mode commands, type a question mark (?) at the command-line prompt.

Possible completions:   
clear          Clear information in the system   
configure      Manipulate software configuration information 
file           Perform file operations
help           Provide help information   
monitor        Show real-time debugging information   
mtrace         Trace multicast path from source to receiver   
ping           Ping remote target   
quit           Exit the management session   
request        Make system-level requests   
restart        Restart software process   
set            Set CLI properties, date/time, craft interface message   
show           Show system information   
ssh            Start secure shell on another host   
start          Start shell   
telnet         Telnet to another host   
test           Perform diagnostic debugging   
traceroute     Trace route to remote host

At the top level of operational mode are a number of broad groups of CLI commands that are used to perform the following functions:

• Control the CLI environment.
• Monitor and troubleshoot the device.
• Connect to other systems.
• Manage files and software images.
• Control software processes.
• Stop and reboot the device.
• Enter configuration mode.

To control the CLI environment, see Configuring the CLI Environment. To enter configuration mode, see CLI Configuration Mode. For information about the other CLI operational mode functions, see the Junos OS Administration Guide for Security Devices.

CLI Configuration Mode

To configure the device, including system parameters, routing protocols, security, interfaces, network management, and user access, you must enter configuration mode. In configuration mode, the CLI provides commands to configure the device, load a text (ASCII) file that contains the device configuration, activate a configuration, and save the configuration to a text file.

You enter configuration mode by entering the configure operational mode command. The CLI prompt changes from user@host> to user@host#.

To view a list of configuration mode commands, type a question mark (?) at the command-line prompt. (You do not need to press Enter after typing the question mark.)

Possible completions:   
Enter                Execute this command   
activate             Remove the inactive tag from a statement   
annotate             Annotate the statement with a comment   
commit               Commit current set of changes   
copy                 Copy a statement   
deactivate           Add the inactive tag to a statement   
delete               Delete a data element   
edit                 Edit a sub-element   
exit                 Exit from this level   
help                 Provide help information   
insert               Insert a new ordered data element   
load                 Load configuration from ASCII file   
quit                 Quit from this level   
rename               Rename a statement   
rollback             Roll back to previous committed configuration   
run                  Run an operational-mode command   
save                 Save configuration to ASCII file   
set                  Set a parameter   
show                 Show a parameter   
status               Show users currently editing configuration   
top                  Exit to top level of configuration   
up                   Exit one level of configuration  
wildcard             Wildcard operations

The Junos OS configuration consists of a hierarchy of statements. There are two types of statements: container statements, which contain other statements, and leaf statements, which do not contain other statements. All the container and leaf statements together form the configuration hierarchy.

Each statement consists of a fixed keyword and, optionally, an identifier that you define, such as the name of an interface or a username.

To configure the device or to modify an existing configuration, you add statements to the configuration with the edit and set configuration mode commands. For more information about the CLI configuration editor and configuration mode, see the Junos OS configuration guides.

CLI Basics

This section contains the following topics:

• Editing Keystrokes
• Command Completion
• Online Help
• Configuring the CLI Environment

Editing Keystrokes

In the CLI, you use keystrokes to move around on and edit the command line, and to scroll through a list of recently executed commands. Table 3 lists some typical CLI editing tasks and the keystrokes that perform them.

Command Completion

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 Spacebar. If the partially typed letters uniquely identify a command, the complete command name appears. Otherwise, a message indicates that your entry is ambiguous or invalid. Possible command completions are displayed if your entry is ambiguous.

You can also use command completion on filenames and usernames. To display all possible values, type one or more characters followed immediately by a question mark. To complete these partial entries, press Tab only. Pressing Spacebar does not work.

Online Help

The CLI provides context-sensitive Help at every level of the command hierarchy. The Help information tells you which commands are available at the current level in the hierarchy and provides a brief description of each.

To get Help while in the CLI, type a question mark (?) in one of the following ways:

• Type a question mark at the command-line prompt. The CLI lists the available commands and options. For examples, see CLI Operational Mode and CLI Configuration Mode.
• Type a question mark after entering the complete name of a command or command option. The CLI lists the available commands and options, then redisplays the command names and options that you typed:
  
  

  user@host# set schedulers ?

  regress@arcona# set schedulers ?
  Possible completions:
  + apply-groups         Groups from which to inherit configuration data
  + apply-groups-except  Don't inherit configuration data from these groups
  > scheduler            Scheduler configuration
  [edit]
  user@host# set schedulers  

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

  user@host> s?

  Possible completions:
    set          Set CLI properties, date/time, craft interface message
    show         Show system information
    ssh          Start secure shell on another host
    start        Start shell
  

When you enter the help commands described in Table 4, the CLI displays usage guidelines and summary information for configuration statements and operational mode commands. You can enter help commands in operational or configuration mode.

Configuring the CLI Environment

You can configure the CLI environment for your current login session. Your settings are not retained when you exit the CLI.

To display the current CLI settings, enter the show cli command:

CLI complete-on-space set to on CLI idle-timeout disabled CLI restart-on-upgrade set to on CLI screen-length set to 49 CLI screen-width set to 132 CLI terminal is 'vt100' CLI is operating in enhanced mode CLI working directory is '/cf/var/home/remote'

To change the CLI environment, use the set cli operational mode command:

Possible completions:   
complete-on-space    Set whether typing space completes current word   
directory            Set working directory   
idle-timeout         Set maximum idle time before login session ends   
prompt               Set CLI command prompt string   
restart-on-upgrade   Set whether CLI prompts to restart after software upgrade   
screen-length        Set number of lines on screen   
screen-width         Set number of characters on a line   
terminal             Set terminal type

Table 5 shows how you can change the CLI environment features.