需求：python 2.6.6升级到python 2.7.9

1. wgt

2. tar xf Python-2.7.9.tgz

3. cd Python-2.7.9

4. ./configure

   make all
   make install
   make clean
   make distclean

5. 按装后python -V 查看当前版本还是python 2.6.6

6. mv /usr/bin/python /usr/bin/python2.6.6

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

   查看版本是python 2.7.9

8. 此时yum不能正常使用，需要做调整

   vim /usr/bin/yum

   将文件头部的

   #!/usr/bin/python
   改成
   #!/usr/bin/python2.6.6