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I have multiple Python versions, and thus also include multiple Python binary executables.

ls /usr/bin/python*

shows the python environments in my ubuntu 18.04

/usr/bin/python   /usr/bin/python2.7           /usr/bin/python2-pbr     /usr/bin/python3    /usr/bin/python3.5m  /usr/bin/python3.6-config  /usr/bin/python3.6m-config  /usr/bin/python3m
/usr/bin/python2  /usr/bin/python2-jsonschema  /usr/bin/python2-wsdump  /usr/bin/python3.5  /usr/bin/python3.6   /usr/bin/python3.6m        /usr/bin/python3-config     /usr/bin/python3m-config

in order to satisfy the PyFlink requirement regarding the Python environment version, i have to choose to soft link python to point to your python3 interpreter:

ln -s /usr/bin/python3 python

however when I use the command, it tells me

ln: failed to create symbolic link 'python': File exists

so i wonder do I need to delete the /usr/bin/python first and then use the command to create the soft link?

user824624
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  • Does this answer your question? [Unable to set default python version to python3 in ubuntu](https://stackoverflow.com/questions/41986507/unable-to-set-default-python-version-to-python3-in-ubuntu) – Sergei Kuzmin Dec 19 '20 at 11:34
  • I have tried it, but it doesn't seem to work out to satisfy the PyFlink requirement, that is why I need to try this – user824624 Dec 19 '20 at 11:37

1 Answers1

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Command ln -s /usr/bin/python3 python creates link ./python pointing to /usr/bin/python3. You probably executed it multiple times so ./python already exists. You could overwrite it by providing -f flag to ln.

You definitely should not delete /usr/bin/python.

The whole idea with manually creating links to Python interpreter to install a package seems very weird. I suggest one of the following options:

  • just use the full path to the interpreter: /usr/bin/python3.6 -m pip install <package>; if the package adds any scripts globally usable from command line, like pyspark, they will be installed with hashbang pointing to the interpreter you installed them with
  • use a virtual environment: /usr/bin/python3.6 -m venv ~/.env-py36; source ~/.env-py36/bin/activate; python -m pip install <package>
  • use something like pyenv
Czaporka
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