[error]: invalid PID number "" in "/var/run/nginx.pid"
That /var/run/nginx/pid file is empty atm.
What do I need to do to fix it?

nginx -s reload is only used to tell a running nginx process to reload its config. After a stop, you don't have a running nginx process to send a signal to. Just run nginx (possibly with a -c /path/to/config/file)

使用方法：

复制代码 代码如下:
nginx -c /path/to/config/file
//我的机器是这样：/alidata/server/nginx/sbin/nginx -c /alidata/server/nginx/conf/nginx.conf