Diagnosing a failed service

Articles

• journalctl — reading the systemd journal — Command for reading the systemd journal with service, time, and other filters.
• curl — HTTP requests from the console — curl sends HTTP and HTTPS requests from the console: status code, headers, the whole exchange, certificate checks.
• systemctl — managing systemd services — Command for managing systemd units and inspecting their state.
• nginx — web server and reverse proxy — A web server and reverse proxy whose configuration should be checked before applying changes.
• less — page through a long file with search — The less pager shows a long file or command output screen by screen — scroll, search by word, follow the end.