在CentOS中使用yum命令出现报错：
`今天想给linux装个git 管理代码
执行命令：
1 yum -y install git
然后出现了这么一句
error:There are no enabled repositories in "/etc/yum.repos.d", "/etc/yum/repos.d
然后就各种找问题，各种查，各种试
比如（别复制这段，这段是错的，解决不了）
vi /etc/yum.repos.dopenEuler_x86_64.repo
#generic-repos is licensed under the Mulan PSL v2.#You can use this software according to the terms and conditions of the Mulan PSL v2.#You may obtain a copy of Mulan PSL v2 at:# .cn/MulanPSL2#THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND, EITHER EXPRESS OR#IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT, MERCHANTABILITY OR FIT FOR A PARTICULAR#PURPOSE.#See the Mulan PSL v2 for more details.[OS]name=OSbaseurl=/openEuler-20.03-LTS/OS/$basearch/enabled=1gpgcheck=1gpgkey=/openEuler-20.03-LTS/OS/$basearch/RPM-GPG-KEY-openEuler[everything]name=everythingbaseurl=/openEuler-20.03-LTS/everything/$basearch/enabled=1gpgcheck=1gpgkey=/openEuler-20.03-LTS/everything/$basearch/RPM-GPG-KEY-openEuler[EPOL]name=EPOLbaseurl=/openEuler-20.03-LTS/EPOL/$basearch/enabled=1gpgcheck=1gpgkey=/openEuler-20.03-LTS/OS/$basearch/RPM-GPG-KEY-openEuler[debuginfo]name=debuginfobaseurl=/openEuler-20.03-LTS/debuginfo/$basearch/enabled=1gpgcheck=1gpgkey=/openEuler-20.03-LTS/debuginfo/$basearch/RPM-GPG-KEY-openEuler[source]name=sourcebaseurl=/openEuler-20.03-LTS/source/enabled=1gpgcheck=1gpgkey=/openEuler-20.03-LTS/source/RPM-GPG-KEY-openEuler[update]name=updatebaseurl=/openEuler-20.03-LTS/update/$basearch/enabled=0gpgcheck=1gpgkey=/openEuler-20.03-LTS/OS/$basearch/RPM-GPG-KEY-openEuler
然**后发现yum源根本没有*
所以，首先先安装yum源*
解决办法
安装yum源
1.进入目录
cd /etc/yum.repos.d
2.查看并删除/etc/yum.repos.d目录下所有的配置文件
1 ll //查看当前目录的所有文件2 rm -rf ./* //删除当前的所有文件
然后会出现(这图是截图人家的，我当时没截图)
2.下载centos8的镜像源
wget -O /etc/yum.repos.d/CentOS-Base.repo /repo/Centos-8.repo
然后会看到这样
接着
ls //查看文件yum -y clean all //清除所有文件yum -y makecache //建立缓存
然后你可能会发现，建立缓存失败
提示是这样
Error: Failed to download metadata for repo 'base'
解决办法
切换源（任选一个命令，我这选的是1 看着来吧）
命令1：
wget -O /etc/yum.repos.d/CentOS-Base.repo /repo/Centos-vault-8.5.2111.repo
命令2：
curl -o /etc/yum.repos.d/CentOS-Base.repo /repo/Centos-vault-8.5.2111.repo
然后再重新建立缓存
yum makecache
如果还不成功就运行这个
yum clear all
然后建立缓存
yum makecache
然后就可以了！反正我到这一步后就可以yum -y install git 了
最后
yum取的源可能是CentOS-Base.repo里面的配置，也可能取的是单个配置文件里面的，比如AppStream的源可能取CentOS-AppStream.repo里面的配置，也可能取CentOS-Base.repo的配置，这两者可能会冲突，也可能不会冲突，不冲突报错可不理，若是报错，建议先重命名备份CentOS-AppStream.repo文件。
yum安装 一直出现There are no enabled repositories in “/etc/yum.repos.d“ “/etc/yum/repos.d“ 的解决办法
