# yum install gcc openssl-devel bzip2-devel # On CentOS systems
# wget https://www.python.org/ftp/python/2.7.18/Python-2.7.18.tgz
# tar xzf Python-2.7.18.tgz
# cd Python-2.7.18
# ./configure --enable-optimizations
# make altinstall
# wget https://bootstrap.pypa.io/pip/2.7/get-pip.py
# python get-pip.py修改文件/usr/bin/yum和/usr/libexec/urlgrabber-ext-down，把首行#!/usr/bin/python修改为#!/usr/bin/python2.7.5
