what config file is nginx using?

while it is running you can check via:

ps uax|grep nginx
root       766  0.0  0.0  41540     4 ?        Ss   Sep16   0:00 nginx: master process /usr/local/vesta/nginx/sbin/vesta-nginx
admin      770  0.0  0.1  41720  1576 ?        S    Sep16   0:01 nginx: worker process                  
root     15197  0.0  0.6  58648  6672 ?        Ss   15:11   0:00 nginx: master process /usr/sbin/nginx -c /etc/nginx/nginx.conf
www-data 15200  0.0  0.7  58652  7228 ?        S    15:11   0:00 nginx: worker process                  
www-data 15201  0.0  1.0  58652 10380 ?        S    15:11   0:01 nginx: worker process                  
www-data 15202  0.0  0.7  58652  7332 ?        S    15:11   0:00 nginx: cache manager process            
root     18720  0.0  0.2  13952  2084 pts/2    S+   16:12   0:00 grep --color=auto nginx

the solution is:

/etc/nginx/nginx.conf

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