Exam JN0-106 Topic 6 Question 40 Discussion

In the Junos OS, the Command Line Interface (CLI) uses distinct prompt symbols to provide the administrator with immediate contextual awareness of their current operating environment. When the prompt ends with a hash symbol (#) , it indicates that the user is in configuration mode .
This mode is the " engine room " of the device, where you modify the candidate configuration. Here, you can add, delete, or modify statements across the various hierarchies like [edit system], [edit interfaces] , or [edit protocols]. It is important to remember that changes made while the # prompt is visible are not active until a commit command is successfully executed.
Contrast this with the operational mode , which is indicated by a greater-than symbol ( > ) . Operational mode is used for monitoring, troubleshooting, and viewing the system status (e.g., show commands). Moving between these modes is a fundamental part of the Junos workflow: you enter configuration mode by typing configure and return to operational mode by typing exit or quit. If you see a percent sign (%), you ' ve wandered into the FreeBSD shell mode , which is a lower-level Unix environment typically reserved for advanced system maintenance. Recognizing that # means you have the power to change the system ' s " brain
" is a key safety check for any network architect.
Reference: User Interfaces, CLI Modes and Navigation.