How to remove python in /usr/local/bin/ [closed]

Question

I have installed Python 2.7.9 in /usr/local/bin. Now it doesn't work any more. I have another Python in /usr/bin/ but in the path is /usr/local/bin/ first. How can i remove the 2.7.9 Python?

Answer 1

Your question is lacking in details, the most pertinent being how you actually installed Python into /usr/local/bin. The installation method would indicate how to remove the installed files.

The most common way of installing packages into the /usr/local hierarchy of directories to is to compile from source and to run sudo make install after compiling and linking. If you didn't already remove the original (uncompressed) source directory, you can change into it and remove the compiled Python package by running:

 sudo make uninstall

If the source code has been deleted, you could try re-downloading the source again.

If there’s no uninstall target for make (unfortunately, more common than you might think), another (inelegant) option is to use the find command to search for all files in /usr/local directory tree that have the same modification time as other files in the application that you want to remove.

These days, I would recommend installing the checkinstall tool. Instead of running make install, this can be used to create an RPM or Debian package which can then be installed (and uninstalled) using the system’s regular software installation tools.

Answer 2

DISCLAIMER: I've since learned a lot, and would recommend setting environment variables for a shell or shell session rather than use this answer. For example, if you manually relink the system's Python2 interpreter to a Python3 interpreter, you may wreak havoc on your system. Please use this answer with caution.

Just reset the symlink.

First, find out which python:

$ which python

In my case, I get:

/usr/local/bin/python

Then find where the symlink points to

$ file /usr/local/bin/python
/usr/local/bin/python: symbolic link to `/usr/bin/python'

Then just repoint the symlink back to the default (in this case, I use the default: /usr/bin/python).

No uninstalls necessary.

Update

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I've since found a lot of better ways to enact this exact same behavior, without having effects on the entire system.

Say I have an undesired python install in /usr/bin, and a desired python install in /opt/bin. Let's say for the point of comparison that the /usr/bin is Python 3.5, and the /opt/bin is Python 2.7. This would create immediate consequences for using the wrong Python interpreter, rather than subtle errors down the line.

Application Defaults

If you would like to (on Linux systems) change which interpeter runs Python scripts, you can change this either via a GUI, or via xdg-mime (a walkthrough can be found here). For macOS or Windows, this can be done easily through a GUI.

Interactive Shell

If you would like to change the default Python for a specific shell, I can see two good ways of doing this. One would be to change the default search PATH to set /opt/bin before usr/bin for a specific situation, however, if you have numerous alternative installs to system packages, this might pose issues too. Another would be to set an alias for Python to the version you want to use. This is the preferred solution, as it only changes the interpreter and is merely a shortcut to reference an existing command.

For example, to set the alias I could use:

alias python="/opt/bin/python"

And to change the default path, I could use:

export PATH=/opt/bin:$PATH

Adding these lines to ~/.bashrc or ~/.bash_aliases (the latter is Ubuntu-only by default) will make these shortcuts be the default on any interactive shell you start. Combining application defaults and interactive shell scripting allows you to have tight control over which interpreter runs your code, but does not require interfering with potentially crucial system files.

Answer 3

Your PATH environment variable. It has a list of directories which bash searches (in the same order) when it's looking for an program to execute. Basically you want to put /usr/local/bin at the start of your PATH environment variable. Add the following to your ~/.bashrc file:

export PATH=/usr/local/bin:$PATH

You can have a look at the current setting by running the set command in bash.

Alternatively, you can simply rename /usr/bin/python to /usr/bin/python2.3 and create a symlink pointing to the new version, e.g.

ln -s /usr/local/bin/python /usr/bin/python