nginx重启 failed (98: Address already in use)

centos6.5，启动nginx服务，无法开启，导致网页打不开。把服务从起一下发现提示错误如下：

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()

问题描述：地址已被使用。可能nginx服务卡死了，导致端口占用，出现此错误。

查看端口

netstat -ntpl

[root@localhost /]# netstat -ntpl
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address               Foreign Address             State       PID/Program name   
tcp        0      0 0.0.0.0:58819               0.0.0.0:*                   LISTEN      2094/rpc.statd      
tcp        0      0 127.0.0.1:3306              0.0.0.0:*                   LISTEN      5060/mysqld         
tcp        0      0 0.0.0.0:21                  0.0.0.0:*                   LISTEN      2294/vsftpd         
tcp        0      0 0.0.0.0:22                  0.0.0.0:*                   LISTEN      2271/sshd           
tcp        0      0 127.0.0.1:631               0.0.0.0:*                   LISTEN      2121/cupsd          
tcp        0      0 :::23527                    :::*                        LISTEN      2094/rpc.statd      
tcp        0      0 :::80                       :::*                        LISTEN      2347/httpd          
tcp        0      0 :::22                       :::*                        LISTEN      2271/sshd           
tcp        0      0 ::1:631                     :::*                        LISTEN      2121/cupsd

kill 2347

[root@localhost /]# service nginx start
Starting nginx:                                            [  OK  ]
[root@localhost /]# ps -ef|grep nginx
root      2816     1  0 11:03 ?        00:00:00 nginx: master process /usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.conf
nobody    2817  2816  0 11:03 ?        00:00:00 nginx: worker process                                          
nobody    2818  2816  0 11:03 ?        00:00:00 nginx: worker process                                          
nobody    2819  2816  0 11:03 ?        00:00:00 nginx: worker process                                          
nobody    2820  2816  0 11:03 ?        00:00:00 nginx: worker process                                          
root      2823  2732  0 11:03 pts/0    00:00:00 grep nginx