Which command is used to check real-time debug output on FortiGate?

The command used to check real-time debug output on FortiGate is "diagnose debug console." This command is specifically designed to display real-time debug output from the FortiGate device directly in the console, allowing the administrator to monitor events and processes as they occur live. This is particularly useful for troubleshooting and diagnosing issues, as it provides immediate feedback from the system.

In contrast, while other commands may provide various types of diagnostic information or status checks, they do not serve the same purpose as the debug console command. For example, "diagnose debug status" offers information about the current configuration of the debug settings but does not show live data. "diagnose real-time output" could be misleading here, as it does not accurately reflect an existing command in the FortiGate command structure for real-time debugging. The command "get debug information" typically retrieves a static set of debug information rather than real-time output.

Thus, using "diagnose debug console" gives administrators an effective tool for immediate monitoring and understanding of the FortiGate's behavior in a live situation.