How-to use journalctl to query systemd logs

Question

How can you use journalctl to review systemd logs?

Answer

When a service is encountering issues but is not logging out to a file, you may be able to get more information by reviewing the systemd journal. 

1. Connect to your server as the root user via SSH or the Terminal in WHM.

2. Use the following command to view the journal:

   # journalctl -u $service

   Note: Replace $service with the name of the service you wish to monitor. For example, the Apache service would be: httpd

Additional filters are available, viewable through journalctl's manual page:

# man journalctl

For example:

• Show the last 'N' lines of the log:

  # journalctl -u $service -n 100

• Show logs for a specific date or time range

  # journalctl -u $service --since "2026-06-01 00:00:00" --until "2026-06-03 23:59:59"