centos7 python2和python3版本共存

安装Python 3.6和pip

[root@iZbp118g1g7ag3ud75297fZ ~]# yum install -y python36 python36-setuptools

update-alternatives分别安装两个版本的python和pip

[root@iZbp118g1g7ag3ud75297fZ ~]# alternatives --install /usr/bin/python python /usr/bin/python2.7 1
[root@iZbp118g1g7ag3ud75297fZ ~]# alternatives --install /usr/bin/python python /usr/bin/python3.6 2
[root@iZbp118g1g7ag3ud75297fZ ~]# mv /usr/bin/pip /usr/bin/pip.bak    # 原有的pip不是软连接，先把它干掉
[root@iZbp118g1g7ag3ud75297fZ ~]# alternatives --install /usr/bin/pip pip /usr/bin/pip2.7 1
[root@iZbp118g1g7ag3ud75297fZ ~]# alternatives --install /usr/bin/pip pip /usr/local/bin/pip3.6 2

检查一下设置是否生效

[root@iZbp118g1g7ag3ud75297fZ ~]# alternatives --display python
python - status is manual.
 link currently points to /usr/bin/python3.6
/usr/bin/python3.6 - priority 2
/usr/bin/python2.7 - priority 1
Current `best' version is /usr/bin/python3.6.

切换python和pip版本

[root@iZbp118g1g7ag3ud75297fZ ~]# alternatives --config python

There are 2 programs which provide 'python'.

  Selection    Command
-----------------------------------------------
*+ 1           /usr/bin/python3.6
   2           /usr/bin/python2.7

Enter to keep the current selection[+], or type selection number: 1  #输入对应版本的序号

后续yum问题

vi /usr/bin/yum
首行的#! /usr/bin/python
都改为#! /usr/bin/python2.7

firewall-cmd也需要手工设置一下

# vim /usr/bin/firewall-cmd
 
首行改为
#!/usr/bin/python2.7 -Es

安装python包

需要将python切换到3.6以后再执行
python -m pip install xmind2testcase

参考：https://blog.csdn.net/lpwmm/article/details/80160242