全局安装：
一、python2的pip安装方法
sudo apt install python-pip
二、python3的pip安装方法
sudo apt install python3-venv python3-pip
验证安装：
symo@symo:~$ which pip3
/usr/bin/pip3
symo@symo:~$ pip3 install inputs
Requirement already satisfied: inputs in /usr/local/lib/python3.7/dist-packages (0.5)
