参考文章:
https://blog.csdn.net/Lv_Victor/article/details/71699078
https://blog.csdn.net/owangf_dl/article/details/78966369
[1] 首先备份/etc/yum.repos.d/CentOS-Base.repo
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
[2] 进入yum源配置文件所在文件夹
cd /etc/yum.repos.d/
[3] 下载163或者阿里云的yum源配置文件,放入/etc/yum.repos.d/(操作前请做好相应备份)
163:
wget http://mirrors.163.com/.help/CentOS6-Base-163.repo
centos5:
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-5.repo
centos6:
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo
centos7:
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
[4]清理
yum clean all
[5]更新缓存
yum makecache
yum install tree -y
yum update -y
yum -y update