in nginx.conf: user root
mkdir:  /var/tmp/nginx/client/
        /ffp/tmp/nginx/proxy/


If you get following error, when you try to start nginx…
[emerg]: bind() to 0.0.0.0:80 failed (98: Address already in use)
Then it means nginx or some other process is already using port 80.
You can kill it using:
sudo fuser -k 80/tcp
And then try restarting nginx again:
service nginx start