python版本升级流程，升级2.7跟3.x版本流程一样

前言：

　　目前python2.6版本很多库已经不支持，在安装库的时候总会遇到很多装不上的事故，特别烦恼，所以以后不纠结，直接升级python版本后再使用，避免多次采坑；当然，未来趋势还是python3.xxx版本，允许条件下，新环境还是用python3.0版本以上比较稳妥。

1.其中一个错误，运行django项目时报错：缺少sqlite3，下面编译需要先安装sqlite3

django.core.exceptions.ImproperlyConfigured: Error loading either pysqlite2 or sqlite3 modules (tried in that order): No module named '_sqlite3'

2.安装Python依赖包：

yum install libffi-devel zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite sqlite-devel readline-devel tk-devel gcc make -y

3.编译安装python

./configure --prefix=/usr/local/python2.7
make
make install

4.安装setuptools

/usr/local/python2.7/bin/python setup.py install

5.安装pip

/usr/local/python2.7/bin/python setup.py install

6.配置环境变量【可以选择不配置】

vim /etc/profile

ulimit -n 65535
PATH=/usr/local/python2.7/bin:$PATH
PATH=/usr/local/python2.7/lib/python2.7/site-packages/django/bin:$PATH

source /etc/profile

7.检查版本

pip -V

pip 19.1.1 from /usr/local/python2.7/lib/python2.7/site-packages/pip-19.1.1-py2.7.egg/pip (python 2.7)


python

Python 2.7.16 (default, Aug 30 2019, 14:50:21) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-23)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
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