/usr/local/nginx

find / -name nginx.conf

nginx -V | grep PRefix
-------------
nginx version: nginx/1.13.9
built by gcc 4.8.5 20150623 (red hat 4.8.5-16) (GCC)
built wITh OPEnSSL 1.0.2k-fips 26 Jan 2017
TLS SNI support enabled
configure arguments: --prefix=/usr/local/nginx --with-http_ssl_module

vim /usr/local/nginx/nginx.conf

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;
 
 ...
}

vim /usr/local/nginx/nginx.conf

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

error_log logs/error.log notice;