41 lines
1.6 KiB
Markdown
41 lines
1.6 KiB
Markdown
# `journalctl` Troubleshooting Guide
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This guide provides a structured approach to troubleshooting common issues in Linux using the `journalctl` command.
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## General Troubleshooting
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1. **Review Recent Logs**
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- View recent log entries: `journalctl -e`
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- Show logs since the last boot: `journalctl -b`
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## Service-Specific Issues
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1. **Identify Service Issues**
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- Display logs for a specific service: `journalctl -u service-name.service`
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- Replace `service-name` with the actual service name, e.g., `journalctl -u sshd`
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## System Crashes or Boots
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1. **Investigate Boot Issues**
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- Display logs from the current boot: `journalctl -b`
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- Show logs from the previous boot: `journalctl -b -1`
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- List boot sessions to identify specific instances: `journalctl --list-boots`
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## Error Messages
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1. **Filter by Error Priority**
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- Show only error messages: `journalctl -p err`
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- For more severe issues, consider using higher priority levels like `crit`, `alert`, or `emerg`
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## Additional Tips
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- **Follow Live Logs**: Monitor logs in real-time: `journalctl -f`
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- **Time-Based Filtering**: Investigate issues within a specific timeframe:
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- Since a specific time: `journalctl --since "YYYY-MM-DD HH:MM:SS"`
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- Between two timestamps: `journalctl --since "start-time" --until "end-time"`
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- **Output Formatting**: Adjust output format for better readability or specific needs:
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- JSON format: `journalctl -o json-pretty`
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- Verbose format: `journalctl -o verbose`
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- **Export Logs**: Save logs for further analysis or reporting:
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- `journalctl > logs.txt` or `journalctl -u service-name > service_logs.txt`
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