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36 lines
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Markdown
36 lines
1 KiB
Markdown
# journalctl
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> Query the systemd journal.
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> More information: <https://manned.org/journalctl>.
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- Show all messages with priority level 3 (errors) from this boot:
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`journalctl {{[-b|--boot]}} {{[-p|--priority]}} 3`
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- Delete journal logs which are older than 2 days:
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`journalctl --vacuum-time 2d`
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- Show only the last `n` lines and follow new messages (like `tail -f` for traditional syslog):
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`journalctl {{[-n|--lines]}} {{n}} {{[-f|--follow]}}`
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- Show all messages by a specific unit:
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`journalctl {{[-u|--unit]}} {{unit}}`
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- Show logs for a given unit since the last time it started:
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`journalctl _SYSTEMD_INVOCATION_ID=$(systemctl show --value --property=InvocationID {{unit}})`
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- Filter messages within a time range (either timestamp or placeholders like "yesterday"):
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`journalctl {{[-S|--since]}} {{now|today|yesterday|tomorrow}} {{[-U|--until]}} "{{YYYY-MM-DD HH:MM:SS}}"`
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- Show all messages by a specific process:
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`journalctl _PID={{pid}}`
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- Show all messages by a specific executable:
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`journalctl {{path/to/executable}}`
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