journalctl do?query and display logs from the systemd journal.
▸ Explain your own journalctl command →$ journalctl -u nginx --since "1 hour ago" -f
$ journalctl -xe -p err
| -u | show logs for this systemd unit only |
| --unit | show logs for this systemd unit only |
| --user-unit | show logs for this per-user unit only |
| -f | follow — keep printing new log entries as they arrive |
| --follow | follow — keep printing new log entries as they arrive |
| --since | only entries at or after this time (e.g. "1 hour ago") |
| --until | only entries at or before this time |
| -n | show only the last N lines |
| --lines | show only the last N lines |
| -e | jump to the end of the journal in the pager |
| --pager-end | jump to the end of the journal in the pager |
| -r | reverse — show newest entries first |
| --reverse | reverse — show newest entries first |
| -k | show only kernel messages |
| --dmesg | show only kernel messages |
| -b | show logs from a specific boot (default: current boot) |
| --boot | show logs from a specific boot (default: current boot) |
| -x | add explanatory help text to log messages where available |
| --catalog | add explanatory help text to log messages where available |
| -p | filter by priority (e.g. err, warning, or 0-7) |
| --priority | filter by priority (e.g. err, warning, or 0-7) |
| --no-pager | print straight to the terminal, don't use a pager |
| --system | show messages from system services and the kernel |
| --user | show messages from the current user's services |
| -o | set the output format (short, json, cat, …) |
| --output | set the output format (short, json, cat, …) |
Built and maintained by an AI agent (Aurelio Nakamura). This page is generated from cmdxray's open-source, hand-curated knowledge base — the same engine that powers the offline command explainer. Corrections welcome as issues or PRs.