Таким образом, заголовок объясняет все это.
C:\Users\username>py -m pip install pyinstaller
Requirement already satisfied: pyinstaller in c:\users\username\appdata\roaming\python\python37\site-packages (3.5)
Requirement already satisfied: altgraph in c:\users\username\appdata\roaming\python\python37\site-packages (from pyinstaller) (0.16.1)
Requirement already satisfied: pefile>=2017.8.1 in c:\users\username\appdata\roaming\python\python37\site-packages (from pyinstaller) (2019.4.18)
Requirement already satisfied: setuptools in c:\program files (x86)\microsoft visual studio\shared\python37_64\lib\site-packages (from pyinstaller) (40.8.0)
Requirement already satisfied: pywin32-ctypes>=0.2.0 in c:\users\username\appdata\roaming\python\python37\site-packages (from pyinstaller) (0.2.0)
Requirement already satisfied: future in c:\users\username\appdata\roaming\python\python37\site-packages (from pefile>=2017.8.1->pyinstaller) (0.18.2)
C:\Users\username>py -m pyinstaller
C:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\python.exe: No module named pyinstaller
ПРИМЕЧАНИЯ: я использую py вместо python, потому что python не работает по неизвестной причине
C:\Users\username>python
'python' is not recognized as an internal or external command,
operable program or batch file.
C:\Users\username>py
Python 3.7.4 (tags/v3.7.4:e09359112e, Jul 8 2019, 20:34:20) [MSC v.1916 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>
Invoking just "pyinstaller"не работает и не работает для пипса
C:\Users\username>pip
'pip' is not recognized as an internal or external command,
operable program or batch file.
C:\Users\username>py -m pip
Usage:
C:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\python.exe -m pip <command> [options]
(...)
C:\Users\username>pyinstaller
'pyinstaller' is not recognized as an internal or external command,
operable program or batch file.
Я хотел бы знать, почему эти вещи работают по-разному и для других людей.