第一步：在centos下面下载 nginx 
         wget http://nginx.org/download/nginx-1.2.9.tar.gz

         解压 tar zxf nginx-1.2.9.tar.gz
第二部：新建一个用户nginx在安装操作
        useradd nginx
        passwd nginx
                --nginx nginx
第三步、解压和测试安装环境 ./configure --prefix=/var/nginx （在客户那里安装到了 /nginx_instal  囧..）
      安装过程中报错

checking for OS
 + Linux 2.6.32-220.el6.x86_64 x86_64
checking for C compiler ... not found

./configure: error: C compiler gcc is not found

解决方法：安装gcc
   yum install gcc

  ./configure: error: the HTTP rewrite module requires the PCRE library.
You can either disable the module by using --without-http_rewrite_module
option, or install the PCRE library into the system, or build the PCRE library
statically from the source with nginx by using --with-pcre=<path> option.

需要安装
  安装pcre-devel解决问题 (root用户下安装)
yum -y install pcre-devel

  继续报错误

./configure: error: the HTTP gzip module requires the zlib library.
You can either disable the module by using --without-http_gzip_module
option, or install the zlib library into the system, or build the zlib library
statically from the source with nginx by using --with-zlib=<path> option.

需要安装 yum install -y zlib-devel

在继续执行 ./configure --prefix=/opt/nginx  安装编译成功

第四步：

make && make install
第五步：

cd /opt/nginx/sin
./nginx

然后打开浏览器输入IP地址  显示
Welcome to nginx!

xxxxxxxxx

安装成功