今天在做LNMP的時候，啟動nginx服務，無法開啟，導致網頁打不開。把服務從起一下發現提示錯誤如下：
Starting 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()
問題描述：地址已被使用。可能nginx服務卡死了，導致端口占用，出現此錯誤。
解決方法：首先用lsof:80看下80端口被什么程序占用。lsof返回結果如下：
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
nginx 3274 root 6u IPv4 10664 0t0 TCP *:http (LISTEN)
nginx 3547 nginx 6u IPv4 10664 0t0 TCP *:http (LISTEN)
發現是nginx程序，所以我們把nginx服務k掉，重新啟動服務。。命令如下:
kill -9 3274
kill -9 3547
service nginx start
Starting nginx: [ OK ]
OK了，服務成功啟動！~~