Which command provides real-time updates of system messages?

The command that provides real-time updates of system messages is tail -f /var/log/syslog. This command uses the tail utility with the -f option, which stands for "follow." When you run this command, it shows the last few lines of the specified log file, in this case, /var/log/syslog, and continues to display new lines as they are added to the file. This is particularly useful for monitoring system logs in real-time, allowing administrators to watch for system events, error messages, or other changes as they occur.

The other commands do not provide the same functionality. For instance, logtail is designed to report new log entries since the last time it was run, but it does not provide continuous, real-time updates like tail -f does. The command tail -n 20 /var/log/messages would show the last 20 lines of the specified log file but would not continue to monitor and display new entries. viewlog is not a standard Linux command and may refer to specific logging utilities on certain systems, but it does not have the same universal applicability as tail -f. Thus, tail -f /var/log/syslog is