systemd is a Linux system and service manager whose journal subsystem, queried with journalctl, collects and stores system logs in a compact binary format. section 3.2.1
The journal is useful when operating systems or virtual machines:
- Query logs interactively or in one-shot commands, including logs for a particular systemd unit and time range. section 3.2.1
- Filter messages by severity, such as showing Error priority and above with --priority=3. section 3.2.1
- Trade familiar text tools such as tail for faster, more compact binary storage and journalctl’s richer interface. section 3.2.1
Inspect a service’s recent logs
journalctl --since "12 hours ago" -u example.service retrieves messages for example.service from the previous twelve hours.
