The Alpine apk upgrade command does not accept -y, so the flag is no longer appended there. The CLI -y option remains available for other package managers.
Use apt-get autoremove --purge instead of a separate empty purge step, and pass the CLI yes flag through to apk upgrade so the logged commands match actual behavior.
Use a temporary file to write the summary header and existing log content, then replace the original log atomically. This removes the dependency on sed for summary insertion and avoids unsafe string interpolation.
Update the README with installation, requirements, supported actions, config format, and usage details. Align the CLI help text with current behavior and add startup checks for required runtime dependencies.