The CLI commands are organized in a hierarchical fashion, with commands that perform a similar function grouped together under the same level. For example, all commands that display information about the system and the 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 2 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 router table, use the command show route brief.
The hierarchical organization results in commands that have a regular syntax and provides several features that simplify use of the CLI:
show commands display software information and statistics, and all clear commands erase various types of system information.
?) at any level, you see a list of the available commands along with a short description of each command. This means that if you already are familiar with the JUNOS software or with other routing software, you can use many of the CLI commands without referring to the documentation.