pip install --upgrade pip 升級導致報錯，解決方法

You are using pip version 7.1.0, however version 20.2.4 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.　　

如上，提示讓升級pip所以就按照提示升級了

隨后導致報錯

[root@vm10-0-1-192 bin]# pip install virtualenvwrapper
Traceback (most recent call last):
  File "/usr/bin/pip", line 7, in <module>
    from pip._internal.cli.main import main
  File "/usr/lib/python2.6/site-packages/pip/_internal/cli/main.py", line 10, in <module>
    from pip._internal.cli.autocompletion import autocomplete
  File "/usr/lib/python2.6/site-packages/pip/_internal/cli/autocompletion.py", line 9, in <module>
    from pip._internal.cli.main_parser import create_main_parser
  File "/usr/lib/python2.6/site-packages/pip/_internal/cli/main_parser.py", line 7, in <module>
    from pip._internal.cli import cmdoptions
  File "/usr/lib/python2.6/site-packages/pip/_internal/cli/cmdoptions.py", line 104
    binary_only = FormatControl(set(), {':all:'})

查了查問題原因是：Python 2.6站點程序包中有一個不支持Python 2.6的pip版本，也就是不支持這樣升級了，python3不影響

找到問題了，就解決當前問題

$ yum remove python-pip

$ cd /usr/local/src
$ wget https://bootstrap.pypa.io/2.6/get-pip.py
$ python get-pip.py

$ pip -V

還原后解決了問題