Sstrhsrtj

So, I wanted to run Python 3.4.x inside a virtualenv virtual environment. I learned that the first step should be to build Python 3.4.x.

I was doing so in /usr/bin/Python3.4.x (a folder I created), where I had extracted Python3.4.x stuff. Then ran ./configure, make, and then did sudo make install. As that command was doing its work, I realized that I might have messed up pretty badly by overwriting core Debian stable Python.

A simple test of running python in terminal shows that I am still using Python 2.7.x, so it seems that I am okay, but I have no clue. Doing something like sudo make uninstall is not an option because I don't think Python makefile comes with uninstall rules for make.

Doing something like sudo apt-get install --reinstall python also doesn't do much, leaving me feeling like I am safe, since reinstall didn't have to overwrite any files?

In any case, I am not sure what I just did, and I am not sure what the consequences are. Could someone help me understand?

I finally understand why the instructions I was following suggest that I configure and make using /opt/some_folder prefix, but its something I omitted...and now...yeah.

First of all: you don't need to build python to run it in a virtualenv, you could have just used the Python3.4.2 provided by the system:

virtualenv -p /usr/bin/python3.4 /path/to/your/venv

You might be in trouble, if you overwrote the system executable and/or its libraries. One of the ways to test this, is running /usr/bin/lsb_release and see if it still works. That is one of the utilities already based on python3 (others are still on python2.7) and it is invoked by apt-get, so when it fails you are in trouble. Try to reinstall python3 if you can, just to make sure you overwrite any traces from your compilation and install.

It would also be good to share, where you got the incorrect information that you need to build python yourself. So people might avoid that information in case it is not corrected.

The problem of overwriting default python version is still actual.

As said in the README.rst, use sudo make altinstall to avoid overriding the OS default version:

On Unix and Mac systems if you intend to install multiple versions of Python
using the same installation prefix (--prefix argument to the configure
script) you must take care that your primary python executable is not
overwritten by the installation of a different version. All files and
directories installed using make altinstall contain the major and minor
version and can thus live side-by-side. make install also creates
${prefix}/bin/python3 which refers to ${prefix}/bin/pythonX.Y. If you
intend to install multiple versions using the same prefix you must decide which
version (if any) is your "primary" version. Install that version using make
install. Install all other versions using make altinstall.

For example, if you want to install Python 2.7, 3.5, and 3.6 with 3.6 being the
primary version, you would execute make install in your 3.6 build directory