Why does 'python3 --version' show 'NameError: name 'python3' is not defined'?

Understanding "python3 --version shows "NameError: name 'python3' is not defined" Error

When executing "python3 --version" from the terminal, you may encounter the "NameError: name 'python3' is not defined" error. This error stems from a common misconception between the Python interpreter and the Python binary.

Python3 is not a Python command; it is the executable program that launches the Python interpreter. When you type "python3 --version," you are instructing the operating system to run the python3 binary and pass the "--version" argument to it. Therefore, this command should be executed in the command line, not within the Python interpreter.

When you are in the interactive Python interpreter, you can only execute Python syntax. If you attempt to run "python3 --version" within the interpreter, it will result in the NameError as the interpreter doesn't recognize "python3" as a valid command.

To fix this issue, exit the Python interpreter and go back to the command line. From the command line, type "python3 --version" and the system will display the correct Python version information. Remember that commands like "pip," "virtualenv," and "conda" also run from the command line and not from within the Python interpreter.

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