Learn to quickly diagnose the “Address already in use” error on Linux by listing listening ports with netstat, ss, and lsof, interpreting their output, filtering results, and freeing conflicted ports, with example commands and explanations of each option.
This guide shows how to quickly locate and resolve the “Address already in use” error on Linux and macOS by using netstat, ss, and lsof to list listening ports, interpret their output, and filter results for specific services or ports.
Learn step‑by‑step how to use netstat, ss, and lsof commands to list listening ports, filter results, and pinpoint the exact process occupying a specific port on Linux and macOS systems.
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