About this article
This article was created using an automated generation workflow utilizing generative AI. Based on the official systemd journal manual, we have outlined how to safely isolate only the time of the incident.
Verification status: 📘 Confirmed with official systemd specifications – Ubuntu physical machine unverified
During log investigation, before running grep on the entire text, narrowing down the time range withjournalctl --since and --until makes it easier to track down potential causes.
- Try this first
- Check this point
- Change one thing
- and compare how the number of lines and events increases.
- after that makes it easier to explain the investigation rationale.
- For inquiries like "unable to connect around 11:20," first narrowing down to 11:15 to 11:25 and then checking the target service helps prevent getting distracted by unrelated errors.
Try this first
journalctl --since "10 minutes ago" --until "now" --no-pager | tail -50
This is read-only, so the logs are not modified.
Check this point
Verify whether the displayed timestamps fall within the last 10 minutes. First, fix the condition of the "time period when the failure occurred" from within the massive amount of logs.
Change one thing
10 minutes agoChange 30 minutes ago to
and compare how the number of lines and events increases.
Why?-u nginxBecause the journal contains timestamp information, you can reduce the candidate set by time condition before performing string searches. Adding unit conditions such as
after that makes it easier to explain the investigation rationale.
For professional use
