What does the '-f' option do when using journalctl?

When using journalctl, the '-f' option is used to follow the log output in real-time. This means that when you execute the command with this option, it continuously displays new log entries as they are written. This functionality is particularly useful for monitoring ongoing processes or troubleshooting services in real time, as it allows administrators to see live changes to the logs without needing to repeatedly refresh or re-query the data.

This real-time capability is akin to using the 'tail -f' command on regular log files, where the display updates automatically as new entries are added. As such, it empowers users to respond immediately to changes and incidents as they occur in the system logs.