PortMon and the port that vanished

Field notes

The utility reads kernel socket tables through libproc rather than invoking lsof or parsing shell output, and the page claims a full scan takes about 5 ms. Its restart flow follows launchers such as npm, Maven, and Cargo, then reruns the original command with its prior directory and environment. Container support is described for Docker Desktop, OrbStack, and Colima, with watched-port presets for databases, queues, and other common development services.