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Could someone explain how to properly install Python 3.5.0 on Ubuntu so that it replaces the system's default Python 3.4.0 as the new default? Installing is the

Could someone explain how to properly install Python 3.5.0 on Ubuntu so that it replaces the system's default Python 3.4.0 as the new default? Installing is the easy part, but I haven't figured out how to also make sure all the libraries that come with Python are also replaced with the 3.5 versions. Thanks!

pixelmonkey 11y ago
I really enjoy using pyenv these days. https://github.com/yyuu/pyenv https://github.com/yyuu/pyenv In that case, `pyenv install 3.5.0` and then `pyenv shell 3.5.0` or `pyenv global 3.5.0` to switch which Python gets used. With pyenv's virtualenv plugin, you can also get rid of the need to use virtualenvwrapper for managing dependencies.
cname 11y ago
I think the only correct way to do this is via 'apt-get upgrade'. In other words, you probably don't want to replace the system Python manually, because a lot of utilities depend on it, and you might bork your system. Using virtualenv is the generally-recommended way to run a different version.
- jessaustin 11y ago
  I've often wondered why utilities that are particular about python versions don't just specify which version they want in the hashbang line. Actually it seems some utilities do exactly that: $ head -1 /usr/bin/lsb_release #! /usr/bin/python3 -Es Obviously, all utilities should do this, and should probably be more specific than that. Distros could have a tool to patch this automatically, and then they wouldn't break when the user chooses to upgrade system python.
slgeorge 11y ago
You probably don't want to do this. For stability it's best to keep the system managed through packages from the standard repositories. If you install things that are not from the repositories the packaging system won't be able to track dependencies - it will have bad information about some capabilities as some items won't have been installed using the packaging system. Overwriting official system libraries is a common cause of problems. It's best to only upgrade something when the repository for your release makes it available: it pays to be conservative about the repositories you use, sticking to the standard ones and thinking very carefully about adding any others (e.g PPA's). If you want 'newer' versions of frameworks/libraries for development then you're better off installing them away from the main system - traditionally that is /usr/local, or using a partitioning system such as chroot. For Python specifically there's a really nice option of use venv/virtualenv.

pixelmonkey 11y ago

I really enjoy using pyenv these days. https://github.com/yyuu/pyenv https://github.com/yyuu/pyenv In that case, `pyenv install 3.5.0` and then `pyenv shell 3.5.0` or `pyenv global 3.5.0` to switch which Python gets used. With pyenv's virtualenv plugin, you can also get rid of the need to use virtualenvwrapper for managing dependencies.

cname 11y ago

I think the only correct way to do this is via 'apt-get upgrade'. In other words, you probably don't want to replace the system Python manually, because a lot of utilities depend on it, and you might bork your system. Using virtualenv is the generally-recommended way to run a different version.

jessaustin 11y ago
I've often wondered why utilities that are particular about python versions don't just specify which version they want in the hashbang line. Actually it seems some utilities do exactly that: $ head -1 /usr/bin/lsb_release #! /usr/bin/python3 -Es Obviously, all utilities should do this, and should probably be more specific than that. Distros could have a tool to patch this automatically, and then they wouldn't break when the user chooses to upgrade system python.

slgeorge 11y ago

You probably don't want to do this. For stability it's best to keep the system managed through packages from the standard repositories. If you install things that are not from the repositories the packaging system won't be able to track dependencies - it will have bad information about some capabilities as some items won't have been installed using the packaging system. Overwriting official system libraries is a common cause of problems. It's best to only upgrade something when the repository for your release makes it available: it pays to be conservative about the repositories you use, sticking to the standard ones and thinking very carefully about adding any others (e.g PPA's). If you want 'newer' versions of frameworks/libraries for development then you're better off installing them away from the main system - traditionally that is /usr/local, or using a partitioning system such as chroot. For Python specifically there's a really nice option of use venv/virtualenv.