我用的虚拟机是VM，Linux版本是CentOS6.3。在安装完Nginx之后，准备启动Nginx服务。
切到目录：
[root@localhost ~]# cd /usr/local/nginx/sbin
[root@localhost sbin]# ./nginx
结果出现了问题：
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] still could not bind()
，Nginx服务使用80端口，看报错信息大概就是80端口已经被占用。
既然80端口已经被占用，那我们就来看看是什么占用了80端口。
[root@localhost ~]# netstat -ntlp|grep 80
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 1468/nginx
看结果，是Nginx进程占用的。那我们就杀死Nginx进程再启动Nginx服务。
首先查看与Nginx有关的进程