Tony can use the `-u` or `--unit` option followed by the name of the systemd unit associated with the application to filter the journal entries and display only the ones related to that application.
For example, if the name of the systemd unit associated with the application is `myapp.service`, Tony can run the following command to display only the journal entries related to that application:
```
journalctl -u myapp.service
```
This will show only the logs that are associated with the `myapp` service and help Tony troubleshoot the errors produced by that application.