Ubuntu18.04安装TensorFlow 遇到错误 No such file or directory: ‘c++‘: ‘c++‘

报错内容如下. No such file or directory: ‘c++’: ‘c++’

Collecting grpcio>=1.8.6 (from tensorflow==1.11.0)
  Using cached https://files.pythonhosted.org/packages/8c/34/7dafc9052bd9b2b41c5a8912aeeca01e179d16de17e9c275633d4b807330/grpcio-1.38.0.tar.gz
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/tmp/pip-build-09xp2toh/grpcio/setup.py", line 255, in <module>
        if check_linker_need_libatomic():
      File "/tmp/pip-build-09xp2toh/grpcio/setup.py", line 205, in check_linker_need_libatomic
        stderr=PIPE)
      File "/usr/lib/python3.6/subprocess.py", line 729, in __init__
        restore_signals, start_new_session)
      File "/usr/lib/python3.6/subprocess.py", line 1364, in _execute_child
        raise child_exception_type(errno_num, err_msg, err_filename)
    FileNotFoundError: [Errno 2] No such file or directory: 'c++': 'c++'

后经过百度, 得知是pip版本太低了. 需要更新. 然后还缺少setuptools
执行下面的命令即可

$ pip3 install --upgrade pip

$ python3 -m pip install --upgrade setuptools

# 最后再执行就可以了
$ pip3 install tensorflow==1.11.0