55 lines
1.2 KiB
Markdown
55 lines
1.2 KiB
Markdown
---
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categories:
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- Linux
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tags: [journaling, systemd, systems-programming]
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---
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# `journald`
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`journald` is a program that comes as default with [systemd](/Linux/systemd.md). It is a service fror collecting and storing system-level log data. I keeps a track of all [kernel](/Operating_Systems/The_Kernel.md) processes. It is invaluable when tracing the source of problems and errors that may arise on the system level. It keeps a track of all kernal processes.
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## `journalctl`
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We use `journalctl` to access the logs. The command by itself outputs the entire log which will be huge and hard to scroll through. We can refine the results with modifiers.
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### View logs for a specific process with pid
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```bash
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journalctl _PID=1234
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```
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### View logs for a specific time period
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This can be really helpful since you can bracket the most recent events which will be more memorable.
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```bash
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journalctl -S -1h
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```
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### View logs for a specfic systemd unit
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```bash
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journalctl -u cronie.service
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```
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### View boot logs
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```bash
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journalctl -b
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```
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#### Identify specific boot
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```bash
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journalctl --list-boots
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```
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### List only kernel entries to the journal
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```bash
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journalctl -k
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```
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