Field NotesAn independent technical notebook
FieldNotes.
Small observations.
Useful experiments.
A clearer view of everyday systems.
Follow your curiosity.
Four ways inField guide / 04
The quiet life
of a DNS lookup.
A name can travel through more than one cache. Knowing where an answer came from changes the next question you ask.
Follow the lookupWorth another look.
All six notes ↗- 012 min read
Read before you restart
Unix · A quiet service is not always a healthy service. Start with a few observations you can compare.
- 052 min read
Make curl part of your notebook
Web · Turn an uncertain web request into a small, repeatable observation.
- 032 min read
Backups you can actually restore
Operations · The useful question is not whether a copy exists. It is whether the recovery path works.
A few useful starting points.
Begin with a little context.
Look at the machine before making a change. These read-only commands give you a compact starting point.
uptime
uname -sr
df -hGive the question a boundary.
Narrow the time window and check the expected listener. Replace the example unit with the service you are investigating.
systemctl status example.service --no-pager
journalctl -u example.service -n 30 --no-pager
ss -lntMake the result repeatable.
Keep a checksum beside a copy and compare it after transfer. Read a saved report before making your next change.
sha256sum example.txt > example.txt.sha256
sha256sum --check example.txt.sha256
wc -l notes.txtGo a little deeper.
Original documentationNotice the detail.
Keep the useful part.
This is a small, growing collection of things that become easier once you write them down.
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