I recently needed to free up disk space by removing old system logs, so I collected the command I used and other useful journalctl commands for future reference.
Disk usage & vacuum (remove old logs)
Show journal disk usage:
sudo journalctl --disk-usageRemove archived journal files until total size is below X:
sudo journalctl --vacuum-size=500MRemove archived journal files older than a time:
sudo journalctl --vacuum-time=3dRemove archived journal files, keeping only the most recent N files:
sudo journalctl --vacuum-files=3Maintenance & troubleshooting
Show journalctl help:
journalctl --helpShow journald service status:
systemctl status systemd-journaldCheck journal file integrity:
sudo journalctl --verify