root 和 alias

location /images {
	root /data/
}

访问此规则时会去你服务器的 /data/images 路径下查找资源

location /images {
	alias /data/
}

访问此规则会去你服务器的 /data/ 路径下查找资源
总结：root 拼接 alias 替换

匹配优先级

1. =
2. ^~
3. ~
4. /

由上向下优先级递减

反斜杠的理解

server {
   listen       80;
   server_name  localhost;

   location /api1/ {
           proxy_pass http://localhost:8080;
        }
   # http://localhost/api1/xxx -> http://localhost:8080/api1/xxx


   location /api2/ {
           proxy_pass http://localhost:8080/;
        }
   # http://localhost/api2/xxx -> http://localhost:8080/xxx


   location /api3 {
           proxy_pass http://localhost:8080;
        }
   # http://localhost/api3/xxx -> http://localhost:8080/api3/xxx


   location /api4 {
           proxy_pass http://localhost:8080/;
        }
   # http://localhost/api4/xxx -> http://localhost:8080//xxx，请注意这里的双斜线，好好分析一下。


   location /api5/ {
           proxy_pass http://localhost:8080/haha;
        }
   # http://localhost/api5/xxx -> http://localhost:8080/hahaxxx，请注意这里的haha和xxx之间没有斜杠，分析一下原因。

   location /api6/ {
           proxy_pass http://localhost:8080/haha/;
        }
   # http://localhost/api6/xxx -> http://localhost:8080/haha/xxx

   location /api7 {
           proxy_pass http://localhost:8080/haha;
        }
   # http://localhost/api7/xxx -> http://localhost:8080/haha/xxx

   location /api8 {
           proxy_pass http://localhost:8080/haha/;
        }
  # http://localhost/api8/xxx -> http://localhost:8080/haha//xxx，请注意这里的双斜杠。
}

此段代码出处