CentOS更新国内镜像源及Python2升3

一起作个记录，在给新书作视频呢
https://www.cnblogs.com/lyz108/p/10293430.html

缺省yum源的服务器通常在国外，安装时速度比较慢。为了提高安装rpm包的速度，可以将yum源配置为国内的阿里repo。

1、先备份系统原有的repo

[root@localhost ~]#cd /etc/yum.repos.d/

[root@localhost yum.repos.d]#ls

CentOS-Base.repo CentOS-Debuginfo.repo CentOS-Media.repo CentOS-Vault.repo webtatic-archive.repo webtatic-testing.repo
CentOS-CR.repo CentOS-fasttrack.repo CentOS-Sources.repo epel.repo

[root@localhost yum.repos.d]#mkdir backup

[root@localhost yum.repos.d]# mv * ./backup/

2、获取阿里centos7的base-repo

[root@localhost yum.repos.d]# wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

[root@localhost yum.repos.d]# ls
backup CentOS-Base.repo

3、清除并重新生成yum cache

[root@localhost yum.repos.d]# yum clean all

[root@localhost yum.repos.d]# yum makecache

4、测试一下新的yum源是否可用

[root@localhost yum.repos.d]# yum install -y screen
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile

• base: mirrors.aliyun.com
• extras: mirrors.aliyun.com
• updates: mirrors.aliyun.com
  Resolving Dependencies
  --> Running transaction check
  ---> Package screen.x86_64 0:4.1.0-0.25.20120314git3c2946.el7 will be installed
  --> Finished Dependency Resolution

Dependencies Resolved

==================================================================================================================================================
Package Arch Version Repository Size
==================================================================================================================================================
Installing:
screen x86_64 4.1.0-0.25.20120314git3c2946.el7 base 552 k

Transaction Summary

Install 1 Package

Total download size: 552 k
Installed size: 914 k
Downloading packages:
screen-4.1.0-0.25.20120314git3c2946.el7.x86_64.rpm | 552 kB 00:00:00
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Installing : screen-4.1.0-0.25.20120314git3c2946.el7.x86_64 1/1
Verifying : screen-4.1.0-0.25.20120314git3c2946.el7.x86_64 1/1

Installed:
screen.x86_64 0:4.1.0-0.25.20120314git3c2946.el7

Complete!

5、获取阿里centos7的epel-repo

[root@localhost yum.repos.d]# wget https://mirrors.aliyun.com/repo/epel-7.repo

6、清除并创建cache

[root@localhost yum.repos.d]# ls
backup CentOS-Base.repo epel-7.repo
[root@localhost yum.repos.d]# yum clean all

[root@localhost yum.repos.d]# yum makecache

至此，大功告成！！！

http://www.acao.cn/os/linux/1173.html

平台：Centos 7

一、安装Python3

yum -y install python3

二、验证Python版本

python -V

显示版本为 Python 2.7.5

python3 -V

显示版本为 Python 3.6.8

三、更新系统文件

cd /usr/bin

mv python python.bak

ln -s python3 python

四、修改yum相关文件

vi /usr/bin/yum

修改首行 #!/usr/bin/python 为 #!/usr/bin/python2

vi /usr/libexec/urlgrabber-ext-down

修改首行 #!/usr/bin/python 为 #!/usr/bin/python2

image

五、再次验证版本

python -V

image