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I am not very experienced at Linux but I recently installed Ubuntu 19.10 and I am trying to use Python 3 and the default is Python 2. I spent a lot of time reading how to configure Ubuntu to run Python 3 but I felt to do it. Can anyone please help me? I used these commands but nothing works...

sudo update-alternatives --list python
sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.7
Eliah Kagan
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user1016220
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    Don't do change default python. It will break many things. – Pilot6 Nov 15 '19 at 19:53
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    https://wiki.ubuntu.com/Python explains Python 3 is the default, not 2.7. – K7AAY Nov 15 '19 at 19:55
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    Might be a classic confusion: `python` *always* refers to Python2 (in accordance with [PEP394](https://www.python.org/dev/peps/pep-0394/)). Don't change that behavior in Ubuntu, or you will break things. However, `python` (py2) is NOT installed by default in newer releases of Ubuntu anymore anyway. Instead, `python3` is installed, and important parts of your system (like apt) rely upon it. Don't change it either. – user535733 Nov 15 '19 at 20:25

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Changing the default Python interpreter is probably no good idea, as system tools could depend on the Python version.

As Python 2 support officially ends at the beginning of 2020, it is certainly a good idea to use Python 3 when you create new projects.

In order to use Python 3, just enter python3 in the terminal.

There is no need to change the default behavior.

Jürgen Gmach
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  • Their must more problem than python 3 issues with ubuntu-19.10 because now the terminal is not responding and I restarted my PC ... – user1016220 Nov 15 '19 at 20:35
  • Assuming all OP wants is to point the command `python` to `python3`, wouldn't modifying `.bashrc` suffice? My understanding is that `.bashrc` is only executed in interactive shells, not scripts and such. – Jack M Nov 15 '19 at 20:48
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    @user1016220 You mentioned terminals not starting; your text terminals (ctrl+alt+f4 etc) should work normally (they don't use python), however some GUI terminals do use python so if you change default behavior in regards python - some GUI terminals may no longer start. That's why you got breakage warnings. You'll just need to use text terminals to undo whatever you did. – guiverc Nov 15 '19 at 21:07