CentOS 更改 yum 镜像源为阿里云镜像源
Step: 1确认 CentOS 版本，在终端中输入 $ cat /proc/version 会得到一下内容，el7 则代表为 CentOS 7 版本。Linux version 3.xx.x-xxxx.xx.x.el7.x86_64 (mockbuild@kbuilder.bsys.centos.org) (gcc version 4.x.x xxxxxxxx (Red Hat 4.x.x-xx) (GCC) ) #1 SMP Tue Jun 23 15:46:38 UTC 2020Step:
