Check Python[edit | edit source]
Check the version of the default Python interpreter:
List the versions of python available:
update-alternatives to setup system-wide ability to choose Python interpreter. The one with the higher priority number will become the default.
update-alternatives --install /usr/bin/python python /usr/bin/python2.7 1
update-alternatives --install /usr/bin/python python /usr/bin/python3.6 2
Now we can list the choices:
update-alternatives --list python
And choose one:
update-alternatives --config python
We can also remove a choice if it's no longer an option on the system:
update-alternatives --remove python /usr/bin/python2.7
Python Virtual Environments[edit | edit source]
See Digital Ocean's quick guide to setting up a local Python programming environment, including virtual environments, which is what I did for SoundScrape Btw, SoundScrape is a neat tool to download sound files from SoundCloud. 
Hynek Schlawack (from 2013)
Python Packaging[edit | edit source]
In the old days (2015) there were still debates about how to package Python and install stuff. Now, it's settled. Use pip. Easy_install is dead. See the docs. Also note that
venv is the successor to
Basic PIP and Virtual Environments[edit | edit source]
Do NOT (normally) use sudo with pip. Use a virtual environment. As of Python 3.4, the command is now called
pyvenv or simply
venv. As of Python 3.6
pyvenv is deprecated in favor of using
python3 -m venv</cod> to help prevent any potential confusion as to which Python interpreter a vritual environment will be based on.
$ python3 -m venv myenv .. some output .. $ source myenv/bin/activate (myenv) $ pip install what-i-want # done using this python? deactivate
You only use sudo or elevated permissions when you want to install stuff for the global, system-wide Python installation.
It is best to use a virtual environment which isolates packages for you. That way you can play around without polluting the global python install.
As a bonus, virtualenv does not need elevated permissions.
- Installing a package is as simple as
pip install foo
- Upgrades are
pip install --upgrade foo
pip uninstall fooif you want to remove foo
- cd mkdir environments cd environments/ pyvenv my_env source my_env/bin/activate pip install --upgrade pip pip install soundscrape pip install soundscrape --upgrade soundscrape https://soundcloud.com/pianoman_weddings/coldplay