How to start nginx via different port(other than 80)

Hi I am a newbie on nginx, I tried to set it up on my server(running Ubuntu 4), which already has apache running. So after I `apt-get install` it, I tried to start nginx. Then I get the message like this: Starting nginx: the configuration file /etc/nginx/nginx.conf syntax is ok configuration file /etc/nginx/nginx.conf test is successful [emerg]: bind() to 0.0.0.0:80 failed (98: Address already in use) [emerg]: bind() to 0.0.0.0:80 failed (98: Address already in use) [emerg]: bind() to 0.0.0.0:80 failed (98: Address already in use) [emerg]: bind() to 0.0.0.0:80 failed (98: Address already in use) [emerg]: bind() to 0.0.0.0:80 failed (98: Address already in use) That makes sense as Apache is using port 80. Then I tried to modify `nginx.conf`, I reference some articles, so I changed it like so: server { listen 8080; location / { proxy_pass http://xx.xx.xx.xx:9500; proxy_set_header Host $host:8080; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Via "nginx"; } After saving this and try to start nginx again, I still get the same error as previously. I cannot really find a related post about this, could any good people shred some light? **I should post all the content in conf here:** user www-data; worker_processes 1; error_log /var/log/nginx/error.log; pid /var/run/nginx.pid; events { worker_connections 1024; # multi_accept on; } http { include /etc/nginx/mime.types; access_log /var/log/nginx/access.log; sendfile on; #tcp_nopush on; #keepalive_timeout 0; keepalive_timeout 65; tcp_nodelay on; gzip on; gzip_disable "MSIE [1-6]\.(?!.*SV1)"; include /etc/nginx/conf.d/*.conf; include /etc/nginx/sites-enabled/*; server { listen 81; location / { proxy_pass http://94.143.9.34:9500; proxy_set_header Host $host:81; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Via "nginx"; } } } mail { See sample authentication script at: http://wiki.nginx.org/NginxImapAuthenticateWithApachePhpScript auth_http localhost/auth.php; pop3_capabilities "TOP" "USER"; imap_capabilities "IMAP4rev1" "UIDPLUS";...