NOTES AFTER HOURS
Practical notes on Linux, small servers, and the web, plus short pieces from after hours.
The Day My Neighbor Borrowed Wi-Fi
A five-minute favor involving Wi-Fi grows into weather reports, printer support, and one unexpectedly formal thank-you gift.
A Gentle First Pass With journalctl
Start with a narrow journalctl query and widen it deliberately instead of scrolling through the entire system journal.
malloc vs new in C++, and Finding the Leak
What malloc and new actually do differently, why the pairs must never cross, and how AddressSanitizer and Valgrind point at the exact line that leaked.
Test Nginx Configuration Before Reloading
Use Nginx's configuration test, inspect included files, and reload without replacing healthy workers with a broken configuration.
journalctl Time Ranges That Save Time
Reduce a large systemd journal to the service, boot, time window, and priority that matter to an incident.
Google Trust Services Certificates with acme.sh: A 2026 Guide
Issue and renew a Google Trust Services certificate with acme.sh, Google Public CA EAB credentials, and a scoped Cloudflare DNS token.
Check DNS With dig Before Changing It
When a DNS change shows up in some places but not others, a few dig queries reveal which layer still has the old answer.
Redis maxmemory and Eviction on a Small Server
Set a Redis memory limit, choose an eviction policy that matches what the keys are for, and use INFO to tell whether Redis is evicting keys or refusing writes.
Cake, but Not Sad Cake
A stranger's grocery list found in a shopping basket turns a routine supermarket trip into a small investigation.
A Chair Left on the Rooftop
One plastic chair on an apartment rooftop quietly becomes the most popular seat in the building.
Nice Place to Sit. No Bus.
Seven strangers wait at a bus stop with a convincing timetable until someone mentions that the route stopped running in March.
A Picnic on the Closed Pier
A cheap ferry ticket leads to an empty pier, a handwritten sign, and an unexpectedly good afternoon.