python2.6升级python2.7

• 1.获取python2.7

wget http://www.python.org/ftp/python/2.7.3/Python-2.7.3.tgz

• 2.解压

tar -xzvf Python-2.7.3.tgz

• 3.创建python2.7文件夹并且安装python2.7

./configure --prefix=/usr/local/python27

make && make install

• 4.备份老python

mv /usr/bin/python /usr/bin/python_old

• 5.为新python建立连接

ln -s /usr/local/python27/bin/python2.7 /usr/bin/python

• 6.查看版本

python -V

• 7.修改yum的配置（不然会报错）

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:
2.7.3 (default, Oct 25 2017, 10:13:29) 
[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

只需要修改/usr/bin/yum文件，将（yum还是用2.6版本）:

#!/usr/bin/python
修改为
#!/usr/bin/python_old

保存退出就搞定