以前每次装Linux，升级Python，都会一堆问题，然后Google，本来想着记录一下，结果问题太多了，也就记不住了，这次特地记了下来。
在CentOS6.8上面安装Python3.5
我的系统是CentOS6.8, 里面默认的Python2.6，如下所示：
[root@linuxtest Downloads]# lsb_release -a LSB Version: :base-4.0-amd64:base-4.0-noarch:core-4.0-amd64:core-4.0-noarch:graphics-4.0-amd64:graphics-4.0-noarch:printing-4.0-amd64:printing-4.0-noarch Distributor ID: CentOS Description: CentOS release 6.8 (Final) Release: 6.8 Codename: Final
1.安装所需依赖包：
yum groupinstall "Development tools" yum 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Python3.5的源码包并编译：
wget https://www.python.org/ftp/python/3.5.0/Python-3.5.0.tgz tar xf Python-3.5.0.tgz cd Python-3.5.0
3. 在安装前先建立一个文件夹：
mkdir /usr/local/python3
4.编译安装：
./configure --prefix=/usr/local/ --with-ensurepip=install
make
make install
5.将以前的Python备份：
mv /usr/bin/python /usr/bin/python_old
6.将Python3链接到Python：
ln -s /usr/local/python3/bin/python3 /usr/bin/python
7.验证：
[root@linuxtest Downloads]# python Python 3.5.0 (default, Dec 16 2016, 14:39:13) [GCC 4.4.7 20120313 (Red Hat 4.4.7-17)] on linux Type "help", "copyright", "credits" or "license" for more information. >>>
顺便说一下，有可能yum会不能用，因为以前的/usr/bin/python指的是Python2.6，但是现在/usr/bin/python指的是Python3.5，所以需要vi /usr/bin/yum,然后将第一行的解释器改为#!/usr/bin/python2.6