I can find the apache process in my Mac by:
$ ps -ef | grep httpd
  0    96     1   0 五10上午 ??         0:03.21 /usr/sbin/httpd -D FOREGROUND
 70   256    96   0 五10上午 ??         0:00.05 /usr/sbin/httpd -D FOREGROUND
 70  4016    96   0 五03下午 ??         0:00.01 /usr/sbin/httpd -D FOREGROUND
 70  4017    96   0 五03下午 ??         0:00.04 /usr/sbin/httpd -D FOREGROUND
 70  4018    96   0 五03下午 ??         0:00.01 /usr/sbin/httpd -D FOREGROUND
501 11243 10710   0 11:40上午 ttys002    0:00.00 grep httpd
you see there is /usr/sbin/httpd running, but how can I know the config file of /usr/sbin/httpd? because there are several apache installed in my Mac.
 
    