Linux / CLI / DevOps

Where Git's user.name comes from. Using --show-origin and --show-scope in a temporary repository, explaining the difference between local and command, and addressing secrets in CI.

Calculate the next execution time of a systemd timer without changing configurations. Review OnCalendar timezone specifications, Persistent, AccuracySec, and differences from actual services.

Compare Linux flock and Windows Named Mutex through the same duplicate execution experiment, covering timeouts, abnormal termination, and deadlocks.

This article explains how to check routes and Path MTU using Linux tracepath, and what to look for when using -n, IPv4/IPv6, and troubleshooting VPNs or size-dependent communication.

This article explains the basic steps and cleanup for using git worktree to open a hotfix branch in a separate folder while keeping the main working tree intact.

This article outlines what Linux df and du measure, and provides a starting point for isolating why the figures do not match during capacity exhaustion, without resorting to deletion.

A practical guide explaining the differences between nginx -t and -T, including safe pre-reload checks, inspecting active included configurations, and precautions when sharing configurations externally.

When reading /proc/self/status from Bash using awk, why does it show awk itself instead of Bash? Safely observe procfs using read-only operations.

Observe dependencies in both the normal and reverse directions without modifying systemd units.

Comparing the human-oriented output of systemctl status with the key=value output of show, leading to monitoring and automated determination.