[root@ceshi ~]# /application/nginx/sbin/nginx -s reload
nginx: [error] invalid PID number "" in "/application/nginx-1.13.3/logs/nginx.pid"

解决的方法：

执行：/application/nginx/sbin/nginx  -c /application/nginx-1.13.3/conf/nginx.conf

然后就可以重新启动了