Nginx Quick Reference

This reference collects the commands and directives you reach for most often when operating Nginx day to day: testing and reloading configuration, the core structure of the config file, common location and proxy patterns, and log/debugging basics. It's intended as a fast lookup rather than a first introduction — each item is deliberately terse, assuming you already understand roughly what Nginx does and just need the exact syntax at hand.

nginx -t tests the configuration syntax without applying it and should be run before every reload; nginx -s reload gracefully reloads config by spawning new workers and letting old ones finish in-flight requests; nginx -s stop performs an immediate shutdown while nginx -s quit performs a graceful shutdown that waits for current requests. On systemd-based systems, systemctl reload nginx and systemctl status nginx are the more common day-to-day equivalents, and journalctl -u nginx surfaces startup errors that don't appear in the access or error log, particularly config errors that prevent Nginx from starting at all.

Nginx config nests in blocks: http { server { location { ... } } }, with directives inheriting downward unless overridden. Common top-level directives include worker_processes, events { worker_connections }, and within http, sendfile on, keepalive_timeout, gzip on, and include /etc/nginx/conf.d/*.conf or sites-enabled/*. Within a server block, listen, server_name, root, and index set the basics, while a location block matches request paths using prefix strings, the = modifier for exact match, and ~ / ~* for case-sensitive/insensitive regex matches respectively.

access_log and error_log directives point to log files (or off to disable); the default error_log level is error, but setting it to debug (requires a debug build) surfaces far more detail when diagnosing a tricky config issue. For redirects, return 301 https://$host$request_uri; inside a port-80 server block is the standard HTTP-to-HTTPS redirect pattern, while rewrite ^/old-path$ /new-path permanent; achieves a similar result for path-level redirects but processes through the rewrite engine rather than short-circuiting immediately like return.