CentOS7.7安装python3.8.2与pip20

1.安装第三方库

#  yum install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gcc make

#  yum install libffi-devel -y

2.下载与安装python3

#  建立新目录
#  sudo mkdir /usr/local/python3 

# 下载安装包
#  wget --no-check-certificate https://www.python.org/ftp/python/3.8.2/Python-3.8.2.tgz

#  解压安装包
#  tar xzvf Python-3.8..tgz

#  cd Python-3.8.

#  编译安装
#  sudo ./configure --prefix=/usr/local/python3

#  sudo make 

#  sudo make install

3、修改系统的默认Python编译器

#  删除默认Python软连接
#  rm /usr/bin/python       

#  创建软链接
# sudo ln -s /usr/local/python3/bin/python3 /usr/bin/python

4.验证python安装

#  python -V

5.用python升级pip

#  python -m pip install --upgrade pip

6、测试安装

# pip -V

7、修改.bashrc文件添加PATH环境变量

#  vim ~/.bashrc

在内容中最后一行添上：

#  export PATH=/usr/local/python3/bin/:$PATH

使环境变量配置生效方法有两种：
（1）关闭当前终端窗口，重新打开一个新终端窗口就能生效
（2）输入“source ~/.bashrc”命令，立即生效

8、编辑yum文件以解决yum报错

#  vim /usr/bin/yum

将yum文件内容中第一行的#!/usr/bin/python2 改为:

#!/usr/bin/python2.

若yum update在执行过程报错，需要将 /usr/libexec/urlgrabber-ext-down 文件的第一行也改为 #!/usr/bin/python2.7