nginx的配置问题：报错

今天第一次用nginx，apt-get安装的，打开nginx.config,里面是这样的

#mail {
#       # See sample authentication script at:
#       # http://wiki.nginx.org/ImapAuthenticateWithApachePhpScript
#
#       # auth_http localhost/auth.php;
#       # pop3_capabilities "TOP" "USER";
#       # imap_capabilities "IMAP4rev1" "UIDPLUS";
#
#       server {
#               listen     localhost:110;
#               protocol   pop3;
#               proxy      on;
#       }
#
#       server {
#               listen     localhost:143;
#               protocol   imap;
#               proxy      on;
#       }

跟那些网上说的不一样啊，这什么情况？怎么设置

开始是nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)

在http里面加了server {
       listen 9000;
，于是nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] bind() to 0.0.0.0:9000 failed (98: Address already in use)
，请这方面熟悉的朋友帮看看