setup nginx web server with PHP

Nginx (engine x) is a high performance lightweight HTTP server, more and more sites are using nginx, according to Netcraft survey (http://news.netcraft.com/archives/2013/11/01/november-2013-web-server-survey.html), nginx powers 15% of the busies sites in November 2013.

Nginx installation is very straight forward, we can download latest source code from http://nginx.org/en/download.html or point our yum source to http://nginx.org/packages/OS/OSRELEASE/$basearch/ and install using yum.
Replace “OS” with “rhel” or “centos”, depending on the distribution used, and “OSRELEASE” with “5” or “6”, for 5.x or 6.x versions, respectively.
So for CentOS 6.3, we can point our YUM source to: http://nginx.org/packages/centos/6/$basearch/

How to get the process listening on certain port

At times we are asked: "what program is listening on port XX?"

In Redhat, we can easily get this using lsof. let's say if we want to know which program is listening on port 80.
[root@localhost ~]# lsof -i :80
COMMAND  PID   USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
httpd   2047   root    4u  IPv6  12636      0t0  TCP *:http (LISTEN)
httpd   2049 apache    4u  IPv6  12636      0t0  TCP *:http (LISTEN)
httpd   2050 apache    4u  IPv6  12636      0t0  TCP *:http (LISTEN)
httpd   2051 apache    4u  IPv6  12636      0t0  TCP *:http (LISTEN)
httpd   2052 apache    4u  IPv6  12636      0t0  TCP *:http (LISTEN)
httpd   2053 apache    4u  IPv6  12636      0t0  TCP *:http (LISTEN)
httpd   2054 apache    4u  IPv6  12636      0t0  TCP *:http (LISTEN)
httpd   2055 apache    4u  IPv6  12636      0t0  TCP *:http (LISTEN)
httpd   2056 apache    4u  IPv6  12636      0t0  TCP *:http (LISTEN)

From the output, we know that httpd is listening on port 80.

Another way to get the process listening on certain port is using netstat.
[root@localhost ~]# netstat -anp | grep 80
tcp        0      0 :::80     :::*            LISTEN      2009/httpd
 
[root@localhost ~]# ps -ef | awk '$2 == 2009'
root      2009     1  0 23:21 ?        00:00:00 /usr/sbin/httpd
 
[root@localhost ~]#
In AIX, most of the time it has no lsof installed, and the netstat is also different from Redhat, but we still can get our question answered.
$ netstat -Aan | grep '.22 ' | grep LISTEN
f1000e0001382bb8 tcp4   0  0  *.22          *.*        LISTEN

$ rmsock f1000e0001382bb8 tcpcb
The socket 0xf1000e0001382808 is being held by proccess 3670142 (sshd).
 
$ ps -ef | grep 3670142
root 3670142 3014676   0   Sep 06      -  0:00 /usr/sbin/sshd

Please note rmsock will not remove the socket, you can confirm this by checking the content of /var/adm/ras/rmsock.log.

reference: http://unix.ittoolbox.com/groups/technical-functional/ibm-aix-l/determine-which-process-is-listening-on-a-port-without-using-lsof-on-aix-1468555