journalctl

Query the systemd journal. More information: https://manned.org/journalctl.

journalctl -b --priority=3

journalctl --vacuum-time=2d

journalctl -f

journalctl -u unit

journalctl _SYSTEMD_INVOCATION_ID=$(systemctl show --value --property=InvocationID unit)

journalctl --since now|today|yesterday|tomorrow --until YYYY-MM-DD HH:MM:SS

journalctl _PID=pid

journalctl path/to/executable