Linux system python2.x upgrade 3.x

1. The python version that comes with the server CentOS7 is 2. I am used to python3. The first step is to upgrade the version.

#Python3.7以上的版本，需要多安装一个依赖包
yum install -y libffi-devel

# 下载
wget https://www.python.org/ftp/python/3.9.1/Python-3.9.1.tgz


# 解压
tar -xzf Python-3.9.1.tgz


#然后 cd Python-3.9.1 文件目录下。创建Python-3.9.1的安装目录：
mkdir  /usr/local/python3/

# 进入python目录
cd Python-3.9.1

#在Python-3.9.1目录下生成安装配置文件：
./configure --prefix=/usr/local/python3


#然后执行编译和安装：
make && make install

Second, modify the system path and point.

After the installation is complete, the next step is to configure system connections and path pointers.

First remove the old python version of centos:

 mv /usr/bin/python /usr/bin/python_old
 mv /usr/bin/pip /usr/bin/pip_old

Finally modify the system soft link:

ln -s /usr/local/python3/bin/python3.9 /usr/bin/python
ln -s /usr/local/python3/bin/pip3.9 /usr/bin/pip

3. Change the yum configuration

Because yum needs to use python2, after changing /usr/bin/python to python3, yum cannot run normally, so you need to change the configuration of yum.

vi /usr/bin/yum
vi /usr/libexec/urlgrabber-ext-down

#!/usr/bin/pythonEdit these two files and change the file header #!/usr/bin/python2to .

4. Whether the verification is successful

python -V

pip -V

Optional: update pip

pip install --upgrade pip