[macos] Locate the nginx.conf file my nginx is actually using

Working on a client's server where there are two different versions of nginx installed. I think one of them was installed with the brew package manager (its an osx box) and the other seems to have been compiled and installed with the nginx packaged Makefile. I searched for all of the nginx.conf files on the server, but none of these files define the parameters that nginx is actually using when I start it on the server. Where is the nginx.conf file that I'm unaware of?

All other answers are useful but they may not help you in case nginx is not on PATH so you're getting command not found when trying to run nginx:

I have nginx 1.2.1 on Debian 7 Wheezy, the nginx executable is not on PATH, so I needed to locate it first. It was already running, so using ps aux | grep nginx I have found out that it's located on /usr/sbin/nginx, therefore I needed to run /usr/sbin/nginx -t.

If you want to use a non-default configuration file (i.e. not /etc/nginx/nginx.conf), run it with the -c parameter: /usr/sbin/nginx -c <path-to-configuration> -t.

You may also need to run it as root, otherwise nginx may not have permissions to open for example logs, so the command would fail.

In addition to @Daniel Li's answer, the nginx installation with Valet would use the Velet configuration as well, this is found in "/usr/local/etc/nginx/valet/valet.conf". The nginx.conf file would have imported this Valet conf file. The settings you need may be in the Valet file.

which nginx

will give you the path of the nginx being used

EDIT (2017-Jan-18)

Thanks to Will Palmer's comment on this answer, I have added the following...

If you've installed nginx via a package manager such as HomeBrew...

which nginx

may not give you the EXACT path to the nginx being used. You can however find it using

realpath $(which nginx)

and as mentioned by @Daniel Li

you can get configuration of nginx via his method

alternatively you can use this:

nginx -V

% ps -o args -C nginx
COMMAND
build/sbin/nginx -c ../test.conf

If nginx was run without the -c option, then you can use the -V option to find out the configure arguments that were set to non-standard values. Among them the most interesting for you are:

--prefix=PATH                      set installation prefix
--sbin-path=PATH                   set nginx binary pathname
--conf-path=PATH                   set nginx.conf pathname

Both nginx -t and nginx -V would print out the default nginx config file path.

$ nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful

$ nginx -V
nginx version: nginx/1.11.1
built by gcc 4.9.2 (Debian 4.9.2-10)
built with OpenSSL 1.0.1k 8 Jan 2015
TLS SNI support enabled
configure arguments: --prefix=/etc/nginx --sbin-path=/usr/sbin/nginx --modules-path=/usr/lib/nginx/modules --conf-path=/etc/nginx/nginx.conf ...

If you want, you can get the config file by:

$ nginx -V 2>&1 | grep -o '\-\-conf-path=\(.*conf\)' | cut -d '=' -f2
/etc/nginx/nginx.conf

Even if you have loaded some other config file, they would still print out the default value.

ps aux would show you the current loaded nginx config file.

$ ps aux
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root        11  0.0  0.2  31720  2212 ?        Ss   Jul23   0:00 nginx: master process nginx -c /app/nginx.conf

So that you could actually get the config file by for example:

$ ps aux | grep "[c]onf" | awk '{print $(NF)}'
/app/nginx.conf