When you first log in to the system you are presented with the CLI.
The initial mode that you see in the CLI is what is called operational mode. This mode provides you with access to run operational commands that enable the display of the state and status of the device. It is in this mode that most users identify what is happening on the device, and perform troubleshooting, as opposed to configuration. The commands in operational mode fall into one of several categories, as listed in Table 3-1.
Table 3-1. Operational command classification
Provides information about the current status of components in the system. Also allows the user to reset the state of some system components.
Allows access to and manipulation of configuration elements of the system.
Diagnostic commands that provide device and network accessibility testing of the system.
Provides access to all of the Junos documentation right from the command line.
Allows the user to connect to other remote systems.
This diverse command set offers you a venerable tool chest to work with on the Junos device. Throughout this chapter, and indeed this entire book, we will use these commands in correlation with real working examples for actual on-box troubleshooting and monitoring.
Most elements in ...