Пип-инсталляция со странным поведением (не проваливается, но также не работает)

У меня есть пункт 8.1.1, который пытается обновить с помощью pip install --upgrade pip. Команда не терпит неудачу, но она ничего не делает. Вывод:

Collecting pip
  Downloading pip-9.0.1-py2.py3-none-any.whl (1.3MB)
    100% |████████████████████████████████| 1.3MB 615kB/s 
Installing collected packages: pip
  Found existing installation: pip 8.1.1
    Not uninstalling pip at /usr/lib/python2.7/dist-packages, outside environment /usr
Successfully installed pip-8.1.1
You are using pip version 8.1.1, however version 9.0.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

Также, возможно, связанный, я пытаюсь установить matplotlib с pip install matplotlib==2.0.0, и я получаю следующий результат:

Collecting matplotlib==2.0.0
  Downloading matplotlib-2.0.0-1-cp27-cp27mu-manylinux1_x86_64.whl (14.6MB)
    100% |████████████████████████████████| 14.6MB 94kB/s 
Requirement already satisfied (use --upgrade to upgrade): numpy>=1.7.1 in /usr/lib/python2.7/dist-packages (from matplotlib==2.0.0)
Collecting cycler>=0.10 (from matplotlib==2.0.0)
  Using cached cycler-0.10.0-py2.py3-none-any.whl
Requirement already satisfied (use --upgrade to upgrade): python-dateutil in /usr/lib/python2.7/dist-packages (from matplotlib==2.0.0)
Requirement already satisfied (use --upgrade to upgrade): functools32 in /usr/local/lib/python2.7/dist-packages (from matplotlib==2.0.0)
Requirement already satisfied (use --upgrade to upgrade): six>=1.10 in /usr/lib/python2.7/dist-packages (from matplotlib==2.0.0)
Requirement already satisfied (use --upgrade to upgrade): pytz in /usr/lib/python2.7/dist-packages (from matplotlib==2.0.0)
Requirement already satisfied (use --upgrade to upgrade): pyparsing!=2.0.0,!=2.0.4,!=2.1.2,!=2.1.6,>=1.5.6 in /usr/lib/python2.7/dist-packages (from matplotlib==2.0.0)
Requirement already satisfied (use --upgrade to upgrade): subprocess32 in /usr/local/lib/python2.7/dist-packages (from matplotlib==2.0.0)
Installing collected packages: cycler, matplotlib
  Found existing installation: cycler 0.9.0
    Not uninstalling cycler at /usr/lib/python2.7/dist-packages, outside environment /usr
Successfully installed cycler-0.9.0 matplotlib-2.0.0
You are using pip version 8.1.1, however version 9.0.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

Но когда я не могу импортировать matplotlib, потому что версия cycler не обновляется.

Итак, я думаю, что это сообщение Not uninstalling pip at /usr/lib/python2.7/dist-packages, outside environment /usr, но я не знаю, что это значит.