如果本机安装了python2，尽量不要管他，使用python3运行python脚本就好，因为可能有程序依赖目前的python2环境，不要动现有的python2环境！
一、安装python3.6
1.安装依赖环境
# yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel
2.下载Python3
wget https://www.python.org/ftp/python/3.6.1/Python-3.6.1.tgz
3.安装python3
mkdir -p /usr/local/python3
解压下载好的Python-3.x.x.tgz包(具体包名因你下载的Python具体版本不不同⽽而不不同，如：我下载的是Python3.6.1.那我这里就是Python-3.6.1.tgz)
#tar -zxvf Python-3.6.1.tgz
4.进入解压后的目录，编译安装。
cd Python-3.6.1
./configure --prefix=/usr/local/python3
make && make install
5.建立python3的软链
ln -s /usr/local/python3/ /usr/bin/python3
6.并将/usr/local/python3/bin加入PATH
#vim ~/.bash_profile
#.bash_profile
#Get the aliases and functions
if [ -f ~/.bashrc ]; then
. ~/.bashrc
fi
User specific environment and startup programs
PATH=$PATH:$HOME/bin:/usr/local/python3/bin
export PATH
按ESC，输入:wq回车退出。
修改完记得执行行下面的命令，让上一步的修改生效：
#source ~/.bash_profile
检查Python3是否正常可用：
#python3 -V
Python 3.6.1
二、安装pip
首先安装setuptools
wget --no-check-certificate https://pypi.python.org/packages/source/s/setuptools/setuptools-19.6.tar.gz
tar -zxvf setuptools-19.6.tar.gz
cd setuptools-19.6.tar.gz
python3 setup.py build
python3 setup.py install
直接安装pip
wget --no-check-certificate https://pypi.python.org/packages/source/p/pip/pip-8.0.2.tar.gz
tar -zxvf pip-8.0.2.tar.gz
cd pip-8.0.2
python3 setup.py build
python3 setup.py install
建立pip3的软链
ln -s /usr/local/python3/bin/pip3 /usr/bin/pip3
#pip3 -V
pip 8.0.2
更换源pip
mkdir ~/.pip
vim ~/.pip/pip.conf
[global]
index-url = https://mirrors.aliyun.com/pypi/simple/
[install]
trusted-host=mirrors.aliyun.com