shell函数-页面跳转练习->

实现思维导图->

实现思路->

分析：
1：先把三个页面的流程作为函数先写下来，定义在脚本的开头，方便下面的调用。
2：先从一个流 程开始做，其他的流程类似，比如nginx
3：整体实现思路是 ，函数调用 ， while do 循环， case in

实现脚本->(仅作为参考练习)

 #!/usr/bin/bash

 Page_first () {
 cat << EOF
 ================
 . 安装Nginx
 . 退出
 ================
 EOF
 }

 Page_Nginx () {
 cat << EOF
 ================
 . 安装Nginx 1.12
 . 源码编译Nginx 1.12
 . 返回上一个页面
 . 退出
 ================
 EOF
 }

 Page_Nginx_Install () {
 cat << EOF
 ================
 . 配置yum仓库
 . 安装Nginx
 . 启动Nginx
 . 返回上一个月面
 . 退出
 ================
 EOF
 }

 Page_Nginx_Install_make () {
 cat << EOF
 ================
 . 准备基础环境，安装依赖包
 . 下载Nginx编译包
 . ./configure
 . make
 . make install
 . 启动
 . 返回上级菜单
 . 退出
 ================
 EOF
 }

 while true
 do
 clear
 Page_first
 read -p "请选择需要安装的编号：" First_page
 case $First_page in
         )
             clear
             while true
             do
             Page_Nginx
             read -p "请选择安装方式：" Nginx_page
             case $Nginx_page in
                     )
                         clear
                         while true
                         do
                         Page_Nginx_Install
                         read -p "请输入进行的步骤：" Nginx_Install
                         case $Nginx_Install in
                             )
                                 clear
                                 if [ -f /etc/yum.repos.d/nginx.repo ];then
                                     echo "yum仓库已有，无需进行配置"
                                 else
                                     cat >/etc/yum.repos.d/nginx.repo <<EOF
 [nginx]
 name=nginx repo
 baseurl=http://nginx.org/pacs/centos/7/x86_64/
 gpgcheck=
 enabled=
 EOF
                                     echo "Nginx的yum仓库配置完成"
                                 fi
                                 ;;
                             )
                                 clear
                                 nginx -v &>/dev/null
                                 if [ $? -eq  ];then
                                     echo "Nginx已安装，无需进行安装"
                                 else
                                     echo "正在安装Nginx"
                                     yum -y install nginx &>/dev/null
                                     if [ $? -ne  ];then
                                         echo "Nginx安装失败，请查找原因"
                                     else
                                         echo "Nginx安装成功"
                                     fi
                                 fi
                                 ;;
                             )
                                 clear
                                 nginx_status=$(systemctl status nginx >/dev/null |grep running |wc -l)
                                 if [ $nginx_status -eq  ];then
                                     echo "Nginx已启动，无需启动"
                                 else
                                     systemctl start nginx  &>/dev/null
                                     if [ $? -ne  ];then
                                         echo "Nginx启动失败，请查找原因"
                                     else
                                         echo "Nginx启动成功"
                                     fi
                                 fi
                                 ;;
                             )
                                 clear
                                 break
                                 ;;
                             )
                                 exit
                                 ;;
                             *)
                                 clear
                                 echo "输入错误，请重新输入"
                         esac
                         done
                         ;;
                     )
                         clear
                         while true
                         do
                         Page_Nginx_Install_make
                         read -p "请输入进行的步骤：" Nginx_make
                         case $Nginx_make in
                             )
                                 clear
                                 echo "正在准备基础环境"
                                 id www &>/dev/null
                                 if [ $? -eq  ];then
                                     echo "基础环境准备完成"
                                 else
                                     groupadd -g  www && useradd -u  -g www www -s /sbin/nologin -M
                                     if [ $? -ne  ];then
                                         echo "基础环境准备失败"
                                     else
                                         echo "基础环境准备完成"
                                     fi
                                 fi
                                 echo "正在安装依赖包"
                                 yum install wget gcc make  pcre-devel  openssl-devel zlib-devel -y &>/dev/null
                                 if [ $? -ne  ];then
                                     echo "依赖包安装失败，请查找原因"
                                 else
                                     echo "依赖包安装成功"
                                 fi
                                 ;;
                             )
                                 clear
                                 echo "正在下载Nginx"
                                 [ -d /server/tools ] || mkdir /server/tools -p
                                 cd /server/tools
                                 wget http://nginx.org/download/nginx-1.14.0.tar.gz &>/dev/null && \
                                 tar xf nginx-1.14..tar.gz &>/dev/null && \
                                 cd nginx-1.14.
                                 if [ $? -ne  ];then
                                     echo "Nginx下载或解压失败，请查看原因"
                                 else
                                     echo "Nginx下载成功"
                                 fi
                                 ;;
                             )
                                 clear
                                 echo "正在执行./configure"
                                 ./configure --prefix=/application/nginx-1.14 --user=www --group=www --with-http_ssl_module --with-http_stub_status_module &>/dev/null
                                 if [ $? -ne  ];then
                                     echo "Nginx执行./configure失败，请查看原因"
                                 else
                                     echo "Nginx执行./configure成功"
                                 fi
                                 ;;
                             )
                                 clear
                                 echo "正在执行make"
                                 make &>/dev/null
                                 if [ $? -ne  ];then
                                     echo "Nginx执行make失败，请查看原因"
                                 else
                                     echo "Nginx执行make成功"
                                 fi
                                 ;;
                             )
                                 clear
                                 echo "正在执行make install"
                                 make install &>/dev/null
                                 if [ $? -ne  ];then
                                     echo "Nginx执行make install失败，请查看原因"
                                 else
                                     echo "Nginx执行make install成功"
                                 fi
                                 ;;
                             )

                                 ;;
                             )
                                 clear
                                 break
                                 ;;
                             )
                                 exit
                                 ;;
                             *)
                                 clear
                                 echo "输入错误，请重新输入"
                         esac
                         done
                         ;;
                     )
                         clear
                         break
                         ;;
                     )
                         exit
                         ;;
                     *)
                         clear
                         echo "输入错误，请重新输入"
                 esac
                 done
             ;;
         )
             exit
             ;;
         *)
             clear
             echo "输入错误，请重新输入"
     esac
 done