通過升級Python後，發現yum命令不能使用了！！！

如何升級Python？詳見

出現如下錯誤：

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:
2.7.12 (default, Feb 28 2017, 14:47:53)
[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

這是因為yum命令是基於Python開發的，當Python升級後，yum命令找不到其所依賴的檔案導致不可用。

如何解決呢？

編輯yum的配置檔案

vi /usr/bin/yum

將檔案首行

#!usr/bin/python

修改為

#!/usr/bin/python2.6.6

儲存退出！

經測試yum可用