if多系统配置yum源

cat yum_if.sh 

 1 #!/bin/bash
 2
 3
 4 #if for many branches yum
 5 #version 1 by feng
 6 
 7 yum_server=192.168.0.117
 8 Os_version=$(cat /etc/redhat-release |awk '{print $4}'|cut -c 1-3)
 9 [ -d /etc/yum.repos.d/bak ]||mkdir /etc/yum.repos.d/bak && mv 
/etc/yum.repos.d/*.repo /etc/yum.repos.d/bak
10 if [ "$Os_version" = "7.4" ] ;then
11     cat >/etc/yum.repos.d/Centos7u4.repo<<-eof
12     [Centos7u4]
13     name=Centos7u4
14     baseurl=http://$yum_server/Base7u4.repo
15     gpgcheck=0
16     eof
17 elif [ "$Os_version" = "6.8" ];then
18     curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo
19 elif [ "$Os_version" = "8.3" ];then
20     curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-8.repo    
21 else
22     echo "error……"    
23 fi

 [root@localhost if]# cat /etc/yum.repos.d/Centos7u4.repo 
 [Centos7u4]
 name=Centos7u4
 baseurl=http://192.168.0.117/Base7u4.repo
 gpgcheck=0
 [root@localhost if]#