[root@localhost system]# nginx
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()
[root@localhost system]# netstat -natp | grep 80
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 11452/nginx: master
tcp 0 0 192.168.122.1:53 0.0.0.0:* LISTEN 8037/dnsmasq
[root@localhost system]# sudo fuser -k 80/tcp
首先我们要弄清楚错误的原因是什么？蜗牛百度了下原因，此错误很指的是80端口被程序占用了。那么解决方法就简单了，强制关闭端口的占用就可以了，一个简单的命令就解决了。
sudo fuser -k 80/tcp #关闭占用80端口的程序
使用后效果如下：
[root@CLOUD711223430 ~]# sudo fuser -k 80/tcp
80/tcp: 2010 2019 2020 2021 2022 2023 2024 2028 2029
使用上面命令后，再重启Nginx就正常了。