Depending upon how you configure the JUNOS software, multiple users can log in to the router, use the CLI, and configure or modify the software configuration.
The JUNOS software provides a general syslog-like mechanism to log system operations, such as when users log in to the router and when they issue CLI commands. To configure system logging, include the syslog statement in the configuration, as described in the section Configure System Logging.
If, when you enter configuration mode, another user is also in configuration mode, a notification message is displayed that indicates who the user is and what portion of the configuration they are viewing or editing:
user@host> configure
Entering configuration mode
Current configuration users:
root terminal p3 (pid 1088) on since 1999-05-13 01:03:27 EDT
[edit interfaces so-3/0/0 unit 0 family inet]
The configuration has been changed but not committed