shell一键配置yum源

#!/bin/bash
read -p "光盘是否已连接(y/n)" a
case $a in
y)
echo "正在配置yum源中"
ping -c5 www.baidu.com &> /dev/null
  if [ $? -eq 0 ];
      then
      mount /dev/sr0 /mnt &> /dev/null
      mkdir -p /etc/yum.repos.d/repo.bak
      mv /etc/yum.repos.d/* /etc/yum.repos.d/repo.bak &> /dev/null
      wget -O /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-7.repo &> /dev/null
      "yum clean all && yum makecache" &> /dev/null
      echo "在线yum源已配置完成"
  else
      mount /dev/sr0 /mnt &> /dev/null
      mkdir -p /etc/yum.repos.d/repo.bak
      mv /etc/yum.repos.d/* /etc/yum.repos.d/repo.bak &> /dev/null
      echo '[local]                                             
name=local                      
baseurl=file:///mnt                     
enabled=1                                               
gpgcheck=0' > /etc/yum.repos.d/local.repo
      "yum clean all && yum makecache" &> /dev/null
      echo "本地yum源已配置完成"
   fi
;;
n)
  echo "请连接光盘再执行该脚本"
;;
*)
  echo "错误命令无法识别"
esac

这里case用的有点蠢了，选择性忽视即可