CentOS更換yum源

# cd /etc/yum.repos.d 

#備份預設yum源

# cp CentOS-Base.repo CentOS-Base.repo_bak

 #下載下傳網易源，阿裡源不行，至少現在很垃圾

# wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.163.com/.help/CentOS7-Base-163.repo  

 #清除系統所有yum源 

# yum clean all 

 #生成yum緩存

# yum makecache 

#安裝epel源

# yum list | grep epel-release.noarch

# yum install epel-release.noarch  

#檢視系統可用的yum源 

# yum repolist enabled 

# yum repolist all