怎么用Shell脚本一键安装Nginx服务

#!/bin/bash
#Nginx版本
ver=nginx-1.$2.$3
# 安装目录
in_dir="/app/$ver"
#软件存放目录
dl_dir="/server"
#最终运行目录
run_dir=/app/nginx
if [ ! -d $in_dir ];then
    mkdir -p $in_dir
fi
if [ ! -d $dl_dir ];then
    mkdir $dl_dir
fi
##安装nginx
function nginx_install (){
yum -y install gcc gcc-c++ pcre-devel zlib-devel openssl-devel 
if [ $? -eq 0 ]
then
    curl  "http://nginx.org/download/$ver.tar.gz" -o $dl_dir/$ver.tar.gz && \ 
    useradd -M -s /sbinlogin nginx  && \
    tar xf $dl_dir/$ver.tar.gz -C $dl_dir  && \
    cd $dl_dir/$ver
    ./configure  --prefix=$in_dir --user=nginx --group=nginx  && \ 
    make  && make install 
fi
}
function nginx_init (){
  ln -s $in_dir $run_dir
}
function nginx_start (){
  ps -ef |grep nginx |grep master
  if [ $? = 0  ];then
        echo "Nginx is Running."
  else
        if [ ! -e $run_dir/sbin/nginx ];then
        nginx_init
        fi
	$run_dir/sbin/nginx
        sleep 5
        ps -ef |grep nginx |grep master
        if [ $? = 0  ];then
        echo "Nginx Start successfully."
        else
        echo "Nginx Failed to Start."
	fi
  fi
}
function nginx_stop (){
	$run_dir/sbin/nginx -s quit	
        sleep 5
        ps -ef |grep nginx |grep master
        if [ $? != 0  ];then
	    echo "Nginx Stop successfully."
        else
            echo "Nginx Failed to Stop."
	fi
}
function nginx_reload (){
	$run_dir/sbin/nginx -s reload 
}
main(){
  nginx_install
  nginx_start
}
case $1 in 
install)
	nginx_install
	nginx_init
	nginx_start
	;;
start)
	nginx_start
	;;
stop)
	nginx_stop
	;;
restart)
	nginx_stop
	nginx_start
	;;
reload)
	nginx_reload
	;;
*)
	echo "使用方法"
	echo "$0 start|stop|restart|reload"	
	echo "安装方法"
	echo "$0 install <版本号> <小版本号>  例如：$0 install 19 3 下载的就是1.19.3版本 "
	;;
esac
#if [ $# = 0 ];then
#	echo  "使用 $0 后面加上小版本号进行部署：例如 $0 19 3 下载的就是1.19.3版本"
#else
#	echo "下载版本：1.$2.$3"
#	echo "安装目录：$in_dir"
#	echo "下载目录：$dl_dir"
#	echo "Nginx installation..." 
#        nginx_install
#        if [ $? != 0 ];then
##	echo "Ngins installation Failed."
#	else 
#        nginx_init
#        nginx_start
#        fi	
#fi