mirror of
https://github.com/ivuorinen/cheatsheet-tldr.git
synced 2026-01-26 11:33:59 +00:00
43 lines
1.2 KiB
Plaintext
43 lines
1.2 KiB
Plaintext
---
|
|
syntax: markdown
|
|
tags: [tldr, linux]
|
|
source: https://github.com/tldr-pages/tldr.git
|
|
---
|
|
# journalctl
|
|
|
|
> Query the systemd journal.
|
|
> See also: `dmesg`.
|
|
> More information: <https://www.freedesktop.org/software/systemd/man/latest/journalctl.html>.
|
|
|
|
- Show all messages with priority level 3 (errors) from this boot:
|
|
|
|
`journalctl {{[-b|--boot]}} {{[-p|--priority]}} 3`
|
|
|
|
- Delete journal logs which are older than 2 days:
|
|
|
|
`journalctl --vacuum-time 2d`
|
|
|
|
- Show only the last `n` lines and follow new messages (like `tail -f` for traditional syslog):
|
|
|
|
`journalctl {{[-n|--lines]}} {{n}} {{[-f|--follow]}}`
|
|
|
|
- Show all messages by a specific unit:
|
|
|
|
`journalctl {{[-u|--unit]}} {{unit}}`
|
|
|
|
- Show logs for a given unit since the last time it started:
|
|
|
|
`journalctl _SYSTEMD_INVOCATION_ID=$(systemctl show --value --property=InvocationID {{unit}})`
|
|
|
|
- Filter messages within a time range (either timestamp or placeholders like "yesterday"):
|
|
|
|
`journalctl {{[-S|--since]}} {{now|today|yesterday|tomorrow}} {{[-U|--until]}} "{{YYYY-MM-DD HH:MM:SS}}"`
|
|
|
|
- Show all messages by a specific process:
|
|
|
|
`journalctl _PID={{pid}}`
|
|
|
|
- Show all messages by a specific executable:
|
|
|
|
`journalctl {{path/to/executable}}`
|