默认的nginx.conf


#user  nobody;
worker_processes  1;

#error_log  logs/error.log;
#error_log  logs/error.log  notice;
#error_log  logs/error.log  info;

#pid        logs/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       mime.types;
    default_type  application/octet-stream;

    #log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
    #                  '$status $body_bytes_sent "$http_referer" '
    #                  '"$http_user_agent" "$http_x_forwarded_for"';

    #access_log  logs/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    #keepalive_timeout  0;
    keepalive_timeout  65;

    #gzip  on;

    server {
        listen       80;
        server_name  localhost;

        #charset koi8-r;

        #access_log  logs/host.access.log  main;

        location / {
            root   html;
            index  index.html index.htm;
        }

        #error_page  404              /404.html;

        # redirect server error pages to the static page /50x.html
        #
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }

        # proxy the PHP scripts to Apache listening on 127.0.0.1:80
        #
        #location ~ \.php$ {
        #    proxy_pass   http://127.0.0.1;
        #}

        # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
        #
        #location ~ \.php$ {
        #    root           html;
        #    fastcgi_pass   127.0.0.1:9000;
        #    fastcgi_index  index.php;
        #    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
        #    include        fastcgi_params;
        #}

        # deny access to .htaccess files, if Apache's document root
        # concurs with nginx's one
        #
        #location ~ /\.ht {
        #    deny  all;
        #}
    }


    # another virtual host using mix of IP-, name-, and port-based configuration
    #
    #server {
    #    listen       8000;
    #    listen       somename:8080;
    #    server_name  somename  alias  another.alias;

    #    location / {
    #        root   html;
    #        index  index.html index.htm;
    #    }
    #}


    # HTTPS server
    #
    #server {
    #    listen       443 ssl;
    #    server_name  localhost;

    #    ssl_certificate      cert.pem;
    #    ssl_certificate_key  cert.key;

    #    ssl_session_cache    shared:SSL:1m;
    #    ssl_session_timeout  5m;

    #    ssl_ciphers  HIGH:!aNULL:!MD5;
    #    ssl_prefer_server_ciphers  on;

    #    location / {
    #        root   html;
    #        index  index.html index.htm;
    #    }
    #}
}

nginx.conf配置文件官方解释

官方文档地址
http://nginx.org/en/docs/
进入nginx.conf配置文件官方解释图示：

原文如下：

nginx consists of modules which are controlled by directives specified in the configuration file. 
Directives are divided into simple directives and block directives. A simple directive consists of the 
name and parameters separated by spaces and ends with a semicolon (;). A block directive has the 
same structure as a simple directive, but instead of the semicolon it ends with a set of additional 
instructions surrounded by braces ({ and }). If a block directive can have other directives inside 
braces, it is called a context (examples: events, http, server, and location).
Directives placed in the configuration file outside of any contexts are considered to be in the main 
context. The events and http directives reside in the main context, server in http, and location in 
server.
The rest of a line after the # sign is considered a comment.

简易翻译：

nginx是由多个模块组成的，而这些模块又是由配置文件nginx.conf中的指定的指令所控制的。
指令可分为简单指令和块指令。
简单指令的结构：name+ 空格+参数值+英文分号。形如这样，worker_processes 1;
块指令由一个或多个简单指令组成，用大括号{}包围起来，如上图。块指令中可以包含其他块指令。
一个块指令我们也可称其为一个上下文context, 这样的上下文/块指令有：
events
http
server
location
nginx.conf配置文件中在以上4个（events、http、server、location）上下文之外的配置指令的地方成为 main 上下文。
以上5个上下文的包含关系如下：
指令最前面的井号 “#” 代表注释