Contos更换python版本

1、查看版本

#python -V
Python 2.6.6

2、安装前准备，安装相关库
#yum install gcc gcc-c++ autoconf automake
#yum install openssl openssl-devel

3、下载安装
#wget https://www.python.org/ftp/python/2.7.11/Python-2.7.11.tgz
#tar -xvzf Python-2.7.11.tgz
#cd Python-2.7.11
#./configure --prefix=/usr/local/python2.7 LDFLAGS='-L../sqlite-autoconf-3140100/.libs' CPPFLAGS='-I../sqlite-autoconf-3140100'
#make
#make install

4、修改python链接指向
#mv /usr/bin/python /usr/bin/python2.6.6.old
#ln -s /usr/local/python2.7/bin/python /usr/bin/python

（上面的l是L，不要写成In了）

查看版本
# python -V
Python 2.7.11

5、修改yum使用的python版本
虽然现在python已经安装完成，但是使用yum命令会有问题——yum不能正常工作：

# yum list
There was a problem importing one of the Python modules
required to run yum. The error leading to this problem was:

No module named yum

Please install a package which provides this module, or
verify that the module is installed correctly.

It's possible that the above module doesn't match the
current version of Python, which is:
2.7.11 (default, Aug 17 2016, 23:54:43) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-17)]

If you cannot solve this problem yourself, please go to 
the yum faq at:
  http://yum.baseurl.org/wiki/Faq
  
这是因为yum默认使用的python版本是2.6.6，到哪是现在的python版本是2.7.11，故会出现上述问题，只需要该一下yum的默认python配置版本就行了：

#vi /usr/bin/yum

将文件头部的#!/usr/bin/python改为

#!/usr/bin/python2.7

#vi /usr/libexec/urlgrabber-ext-down

将文件头部的#!/usr/bin/python改为

#!/usr/bin/python2.7

6、修改环境变量

$vim ~/.bash_profile

修改为：

PYTHON_HOME=/usr/local/python2.7

PATH=$PATH:$HOME/bin:$PYTHON_HOME/bin

$source .bash_profile

7、原有的pip引用的路径需要更改，方法跟上面修改python创建软链接一样。

#mv /usr/bin/pip /usr/bin/pip.old
#ln -s /usr/local/python2.7/bin/pip /usr/bin/pip

#mv /usr/bin/pip2 /usr/bin/pip2.old
#ln -s /usr/local/python2.7/bin/pip2 /usr/bin/pip2

#mv /usr/bin/pip2.7 /usr/bin/pip2.7.old
#ln -s /usr/local/python2.7/bin/pip2.7 /usr/bin/pip2.7