码农志之前一篇文章介绍了《Centos6.8升级Python2.6为Python2.7》，升级完毕后通过pip安装依赖时不再提示版本过期，但是随之而来的问题就是yum不好使了，例如会出现如下报错
[root@tvzr ~]# yum search jpegoptim 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: 2.7.13 (default, May 15 2017, 11:00:16) [GCC 4.4.7 20120313 (Red Hat 4.4.7-18)] If you cannot solve this problem yourself, please go to the yum faq at: http://yum.baseurl.org/wiki/Faq
问题原因是因为yum不支持python2.7的版本，那么只需要在/usr/bin/yum中将第一行的#!/usr/bin/python更换为低版本即可。
vim /usr/bin/yum
原来的头部声明
#!/usr/bin/python
更换以后的头部声明
#!/usr/bin/python2.6
这个python2.6怎么来的呢？
ll /usr/bin/py*
这里就会看到系统自带的以及我们升级后的python
[root@tvzr ~]# ll /usr/bin/py* -rwxr-xr-x 1 root root 78 Aug 18 2016 /usr/bin/pydoc lrwxrwxrwx 1 root root 34 May 15 11:03 /usr/bin/python -> /usr/local/python2.7/bin/python2.7 lrwxrwxrwx 1 root root 6 Apr 16 23:02 /usr/bin/python2 -> python -rwxr-xr-x 2 root root 4864 Aug 18 2016 /usr/bin/python2.6 lrwxrwxrwx 1 root root 34 May 15 11:09 /usr/bin/python2.7 -> /usr/local/python2.7/bin/python2.7 -rwxr-xr-x 2 root root 4864 Aug 18 2016 /usr/bin/python_old
按下esc,并且键入:wq即可保存修改。那么现在yum包管理器就好使了：
[root@tvzr ~]# yum search jpegoptim Loaded plugins: fastestmirror Repository epel is listed more than once in the configuration Loading mirror speeds from cached hostfile * base: mirrors.aliyun.com * epel: mirrors.aliyun.com * extras: mirrors.aliyun.com * updates: mirrors.aliyun.com base | 3.7 kB 00:00 epel | 4.3 kB 00:00 epel/primary_db | 5.9 MB 00:05 extras | 3.4 kB 00:00 updates | 3.4 kB 00:00 ======================================================================================================== N/S Matched: jpegoptim ======================================================================================================== jpegoptim.x86_64 : Utility to optimize JPEG files Name and summary matches only, use "search all" for everything.
