【重要】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，
比如yum！！！！！
不要动现有的python2环境！
第一步：下载：
输入下载命令：wget https://www.python.org/ftp/python/3.6.2/Python-3.6.2.tgz
或者下载好上传也可以
第二步：安装依赖环境
yum -y install zlib zlib-devel yum -y install bzip2 bzip2-devel yum -y install ncurses ncurses-devel yum -y install readline readline-devel yum -y install openssl openssl-devel yum -y install openssl-static yum -y install xz lzma xz-devel yum -y install sqlite sqlite-devel yum -y install gdbm gdbm-devel yum -y install tk tk-devel yum -y install libffi libffi-devel
或者一步到位：
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
第三部：解压
mkdir -p /usr/local/python3
tar -zxvf Python-3.6.2.tgz -C /usr/local/
第四部：安装
cd /usr/local/Python-3.6.2
./configure --prefix=/usr/local/python3
遇到报错：no acceptable C compiler found in $PATH
解决：yum install gcc.x86_64
重新执行：./configure --prefix=/usr/local/python3
make && make install (或者两部分开执行，先make,在执行make install)
第五步：建立python3的软连接
ln -s /usr/local/python3/bin/python3 /usr/bin/python3
ln -s /usr/local/python3/bin/pip3 /usr/bin/pip3
第六步：将/usr/local/python3/bin加入PATH
进入飘目录：cd
ll -a
vi .bash_profile
# .bash_profile
# Get the aliases and functions
if [ -f ~/.bashrc ]; then
. ~/.bashrc
fi
# User specific environment and startup programs
PATH=$PATH:$HOME/bin
PATH=$PATH:$HOME/bin:/usr/local/python3/bin
export PATH
source ~/.bash_profile
第七步：查看：
python3 -V
pip3 -V