How do I use brew installed Python as the default Python? - python

I try to switch to Homebrew (after using fink and macport) on Mac OS X 10.6.2. I have installed python 2.7 with
brew install python
The problem is that, contrary to Macport, it seems that there is no python_select utility, and my default mac python is always default
which python
give me
/usr/bin/python
and /usr/bin/python is not a symlink
How can I do to make python brew flavour to be my default python ?

As suggested by the homebrew installer itself, be sure to add this to your .bashrc or .zshrc:
export PATH="/usr/local/opt/python/libexec/bin:$PATH"

As you are using Homebrew the following command gives a better picture:
brew doctor
Output:
==> /usr/bin occurs before /usr/local/bin This means that system-provided programs will be used instead of those provided by
Homebrew. This is an issue if you eg. brew installed Python.
Consider editing your .bash_profile to put: /usr/local/bin ahead of
/usr/bin in your $PATH.

See: How to symlink python in Homebrew?
$ brew link --overwrite python
Linking /usr/local/Cellar/python/2.7.3... 28 symlinks created
$ which python
/usr/local/bin/python

Quick fix:
Open /etc/paths
Change the order of the lines (highest priority on top)
In my case /etc/paths looks like:
/usr/local/bin
/usr/local/sbin
/usr/bin
/bin
/usr/sbin
/sbin
If you want to know more about paths in OSX I found this article quite useful:
http://muttsnutts.github.com/blog/2011/09/12/manage-path-on-mac-os-x-lion/

I did "brew install python" for OSX High Sierra. The $PATH had /usr/local/bin before any other path but still which python was pointing to the system's python.
When I looked deeper I found that there is no python executable at /usr/local/bin. The executable is named python2. To fix this problem create a symbolic link python pointing to python2:
/usr/local/bin $: ln -s python2 python

For Apple Silicon machines, the path are slightly different. After running brew install python, you must ensure your ~/.zshrc uses the correct Homebrew paths:
# Homebrew
eval "$(/opt/homebrew/bin/brew shellenv)"
# Homebrew: Python
export PATH="/opt/homebrew/opt/python/libexec/bin:$PATH"
Results:
% which python
/opt/homebrew/opt/python/libexec/bin/python
% python --version
Python 3.9.9
% which pip
/opt/homebrew/opt/python/libexec/bin/pip
% pip -V
pip 21.3.1 from /opt/homebrew/lib/python3.9/site-packages/pip (python 3.9)

python formula now uses python3(v3.6.5 for now), brew will link the directory:
/usr/local/opt/python -> ../Cellar/python/3.6.5
it will also link the binary:
/usr/local/bin/python3 -> ../Cellar/python/3.6.5/bin/python3
If you still need to use python2.x, use:
brew install python#2
To use homebrew's python, just put its directory in PATH, for bash:
export PATH="/usr/local/opt/python/libexec/bin:$PATH"
for fish:
set -x PATH /usr/local/opt/python/libexec/bin $PATH
Note:
doing this will shadow the system default version of python
homebrew used to link python to /usr/local/share/python in older versions.

Homebrew does NOT replace stuff in "/usr/bin". You'll just want to put "/usr/local/bin" ahead of "/usr/bin" in your path, then "which python" will give you "/usr/local/bin/python".
Replacing /usr/bin/python (or /usr/bin/ruby) is highly unrecommended.

Modify your $PATH, Add this in your bashrc or bash_profile:
export PATH=/usr/local/bin:/usr/local/sbin:~/bin:$PATH
more click here:
Issue #89791

I did brew install python, my $PATH was good, but still, which python gave me the system installed one. Restarting the terminal fixed it.

You need to edit your PATH environmental variable to make sure wherever the homebrew python is located is searched before /usr/bin. You could also set things up in your shell config to have a variable like PYTHON be set to your desired version of python and call $PYTHON rather than python from the command line.
Also, as another poster stated (and especially on mac) DO NOT mess with the python in /usr/bin to point it to another python install. You're just asking for trouble if you do.

python now points to python3, if you need python 2 then do:
brew install python#2 and then in your .zshrc or .bashrc file
export PATH="/usr/local/opt/python#2/libexec/bin:$PATH"
Now, pyhon --version = Python 2.7.14 and python3 --version = Python 3.6.4.
That's the behavior I'm used to seeing in my terminal.

I believe there are means to make homebrew python default, but in my opinion the proper way to solve a problem is not to mess with system python paths: it is better to create a virtualenv in which homebrew python would be default (by using virtualenv --python option). Using tools like python_select is almost always a bad idea.

Use pyenv instead to install and switch between versions of Python. I've been using rbenv for years which does the same thing, but for Ruby. Before that it was hell managing versions.
Consult pyenv's github page for installation instructions. Basically it goes like this:
- Install pyenv using homebrew. brew install pyenv
- Add a function to the end of your shell startup script so pyenv can do it's magic. echo -e 'if command -v pyenv 1>/dev/null 2>&1; then\n eval "$(pyenv init -)"\nfi' >> ~/.bash_profile
Use pyenv to install however many different versions of Python you need. pyenv install 3.7.7.
Set the default (global) version to a modern version you just installed. pyenv global 3.7.7.
If you work on a project that needs to use a different version of python, look into pyevn local. This creates a file in your project's folder that specifies the python version. Pyenv will look override the global python version with the version in that file.

Add the /usr/local/opt/python/libexec/bin explicitly to your .bash_profile:
export PATH="/usr/local/opt/python/libexec/bin:$PATH"
After that, it should work correctly.

Just do:
brew install python
brew link python
After doing that, add this to your bashrc or bash_profile:
alias python='/usr/local/bin/python2'
Enjoy!

You can edit /etc/paths. Here is mine:
/usr/local/bin
/usr/bin
/bin
/usr/sbin
/sbin
Then add a symlink for the python version. In my case
$ cd /usr/local/bin
$ ln -s python3 python
Voila!

If you are fish shell
echo 'set -g fish_user_paths "/usr/local/opt/python/libexec/bin" $fish_user_paths' >> ~/.config/fish/config.fish

try this
which python3
Try typing python3 instead of just python

Greeting folks! I have the need to use python 3.10 version to harness its new features. My solved solution at 2022-07-03 is as follows. Have fun coding python!
» rm '/usr/local/bin/pip3.10'
» brew link python#3.10
» echo 'export PATH="/usr/local/opt/python#3.10/bin:$PATH"' >> ~/.zshrc
» python3
Python 3.10.5 (main, Jun 23 2022, 17:15:25) [Clang 13.1.6 (clang-1316.0.21.2.5)] on darwin
Type "help", "copyright", "credits" or "license" for more information.

Since High Sierra, you need to use:
sudo chown -R $(whoami) $(brew --prefix)/*
This is because /usr/local can no longer be chowned

brew link python
And you must create/add an alias for python and put it in your .zprofile (Located in Users/username folder, if you press Shift+command+.
This must point to your homebrew python installation location.
alias python ='opt/homebrew/bin/python3'

No idea what you mean with default Python. I consider it bad practice to replace the system Python interpreter with a different version. System functionality may depend in some way on the system Python and specific modules or a specific Python version. Instead install your custom Python installations in a safe different place and adjust your $PATH as needed in order to call you Python through a path lookup instead of looking for the default Python.

Related

brew installs latest python3 but python3 not updated?

Hello I'm trying to upgrade my python from macos
I enter command 'brew upgrade python3' and it tells me the latest version is installed (Warning: python3 3.9.1_8 already installed)
but then when I type 'python3 -V' it returns 'Python 3.6.1'
and when I try to 'brew link --overwrite python#3.9' the operation proceeds successfully but there is still no change.
What am I missing? Why am I not able to use Python3.9?
Most likely the PATH variable in your environment is not configured correctly and the shell is finding the wrong python3.
You can check for the path to the current python3 command using:
which python3
Most likely the output will not be pointing at the brew installation that is usually:
/usr/local/bin/python3
If that was the case check the PATH variable in your environment using:
echo $PATH
or:
env | grep PATH
and check whether /usr/local/bin is present in the PATH variable and that it has precedence over the folder where your current python3 is located.
Change it by edited the .profile file in your home directory by adding:
export PATH="/usr/local/bin:$PATH"
I highly recommend that you install and use pyenv. It is somewhat standard way of managing multiple Python versions on your Mac. I have 4 different Python versions, and switch from one to the other with ease. It can do a lot more than just set your global Python version. Check it out: https://github.com/pyenv/pyenv. It can be installed with brew pyenv.

Python not showing correct version on Mac OSX

I am trying to update Python to 3.7.4 on my Mac. Currently when I type python3 --version, it shows that I have Python 3.7.3 I have tried to update using just the standalone installer from the website as well as homebrew but even through all of these methods, python3 --version still returns to me 3.7.3. Even when I try to upgrade with Brew, it says that 3.7.4 is installed...
Picture for reference:
Please help and thank you in advance!
Update: Check what python version you are using by running which python, at this point you might figure out what version of Python is being used to solve this problem. Otherwise, follow up this steps:
I would remove all Python installations and use Homebrew to install it.
First, run which python:
/Library/Frameworks/Python.framework/Versions/2.7/bin/python
Delete the entire Python.framework directory from /Library/Frameworks.
Second, run which python3:
/usr/local/bin/python3
Again, delete the entire python3 directory.
Now use brew doctor in order to see possible issues with symlinks. If you have issues run brew prune or brew cleanup --prune. This will remove all of the symlinks.
Reinstall python and python3 via homebrew:
brew install python
Some older apps may count on the Python2.7 framework being installed. It sounds like you may not have your bash $PATH set to look for homebrew binaries before the built-in ones. You can edit your ~/.profile file, and make sure that /usr/local/bin is the first entry by adding the following line to the end of .profile:
export PATH=/usr/local/bin:$PATH
ln -s -f /usr/local/bin/python /usr/local/bin/python
https://dev.to/malwarebo/how-to-set-python3-as-a-default-python-version-on-mac-4jjf
Just type in the below and it'll work
python3 --version

Which python am I using?

Having trouble making sure I'm actually using the latest versions of Python even though they are already installed via homebrew.
$ brew upgrade python3
Error: python3 3.6.2 already installed
but:
$ python3 --version
Python 3.6.0
same goes for python2:
$ brew upgrade python
Error: python2 2.7.13_1 already installed
$ python --version
Python 2.7.10`
❯ echo `which python`
If this doesn't print '/usr/local/bin/python' (where brew actually installs binaries), then there's something wrong with your $PATH (probably '/usr/local/bin' is not there or it's inserted after '/usr/bin', so the system default python is being run instead).
++ it seems that brew names its python2.7 as python2 by default, and not as python, so you may also need to create a python2->python link in /usr/local/bin directory.
Do you have separate environment variables set up for each?
I have found in the past that having multiple versions of python 2 for example, without all the environment variables, can get quite confusing!
You may find when typing python3, windows is only looking at python 3.0, unless you are in the python 3.6.2 directory.
First I modified my $PATH: sudo nano /etc/paths so that /Library/Frameworks/Python.framework/Versions/3.6/bin was not being invoked. I made sure my paths were in the right order so that python looked for /usr/local/bin/python3 and /usr/local/bin/python2 first to force the issue.
However, $ python3 --version still returned
Python 3.6.0, though brew says python3 3.6.2 already installed.
brew doctor to the rescue: homebrew recommended a couple things. python was incorrectly symlinked so I ran brew --overwrite python3. Finally, it diagnosed python coming from /Library/Frameworks/Python.framework/Versions/3.6/bin, so I sudo rm -rf /Library/Frameworks/Python.framework. Now python versions are correct.
Homebrew brew doctor warning about /Library/Frameworks/Python.framework, even with brew's Python installed
Thank you everyone for your help.

How do I make Python 3.5 my default version on MacOS?

I have just installed Python 3.5.1 on my Mac (running the latest version of OSX). My system came with Python 2.7 installed. When I type IDLE at the Terminal prompt my system pulls up the original Python 2.7 rather than the newly installed Python 3.5. How do I get my system to default to Python 3.5.1 when I open the IDLE window from Terminal?
Since Python 2 and 3 can happily coexist on the same system, you can easily switch between them by specifying in your commands when you want to use Python 3.
So for Idle, you need to type idle3 in the terminal in order to use it with Python 3 and idle for using it with Python 2.
Similarly, if you need to run a script or reach a python prompt from the terminal you should type python3 when you want to use Python 3 and python when you want to use Python 2.
It's good practice to have your MacOS Python environment set up properly from the beginning making sure that Homebrew installations take precedence over stock MacOS binaries. You want it in usr/local/bin not MacOS default usr/bin.
.bash_profile
# Ensure user-installed binaries take precedence
export PATH=/usr/local/bin:$PATH
# Load .bashrc if it exists
test -f ~/.bashrc && source ~/.bashrc
Can also create aliases for both.
alias py2='python2.7'
alias py3='python3.6'
Source the file to ensure it takes effect for the current session
source ~/.bash_profile
Homebrew install and setup etc...
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
brew doctor
brew update
brew upgrade --all
brew cleanup
Python3 install
brew install python3
Next
pip3 install virtualenv
Next
pip3 install virtualenvwrapper
When all is finished python3, pip3, virtualenv, and virtualenvwrapper.sh will all be in usr/local/bin.
Result
Every time I install anything or use commands like mkvirtualenv Python 3 is used by default.
You can use the python3 command (instead of using python), or you can simply uninstall the 2.7 version if you don't use it
If you dont have any python 2 scripts that you use, you can delete python2. But its not a problem to have them both installed. You just have to use another path python3 to launch IDLE.
I would prefer to let them both installled so if you have any scripts that are in python 2 you can still run them or you have to port them to python3.
You can switch to any python version in your project by creating a virtual environment.
virtualenv -p /usr/bin/python2.x (or python 3.x)
In case you just want to run a program in a specific version just open shell and enter python2.x or python3.x
Do right thing, do thing right!
Open your terminal,
input python -V, It likely shows:Python 2.7.10
input python3 -V, It likely shows:Python 3.7.2
input where python or which python, It likely shows:/usr/bin/python
input where python3 or which python3, It likely shows:
/usr/local/bin/python3
add the following line at the bottom of your PATH environment variable file in ~/.profile file or ~/.bash_profile under Bash or ~/.zshrc under zsh.
alias python='/usr/local/bin/python3'
OR
alias python=python3
input source ~/.bash_profile under Bash or source ~/.zshrc under zsh.
Quit the terminal.
Open your terminal, and input python -V, It likely shows:
Python 3.7.2
Note, the ~/.bash_profile under zsh is not that ~/.bash_profile.
The PATH environment variable under zsh instead ~/.profile (or ~/.bash_file) via ~/.zshrc.
Hope this helped you all!
By typing python, you are actually referring to a link.
You will find its location with $ which python. In my case it was /usr/local/bin/python. go there $open /usr/local/bin/ and just delete the original python, python-config and idle as they are
identical to the 2.7 files in the same folder.
Then duplicate the 3.5 files and rename them to what you just deleted.
This also changes the default link other editors like Sublime_ReplPython use and updates it therefore to the 3.5 Version. This was my major concern with the standard installation.

How do I uninstall python from OSX Leopard so that I can use the MacPorts version?

I want to use the macports version of python instead of the one that comes with Leopard.
Don't. Apple ships various system utilities that rely on the system Python (and particularly the Python "framework" build); removing it will cause you problems.
Instead, modify your PATH environ variable in your ~/.bash_profile to put /opt/local/bin first.
I have both installed:
$ which python
/usr/bin/python
$ which python2.5
/opt/local/bin/python2.5
I also added the following line to my .profile:
export PATH=/opt/local/bin:/opt/local/sbin:$PATH
Use the python_select port to switch python interpreters.
sudo port install python25
sudo port install python_select
sudo python_select python25
This will symlink /opt/local/bin/python to the selected version. Then export PATH as described above.
python_select is now deprecated, use this instead:
sudo port select python python26
Instead of uninstalling the built-in Python, install the MacPorts version and then modify your $PATH to have the MacPorts version first.
For example, if MacPorts installs /usr/local/bin/python, then modify your .bashrc to include PATH=/usr/local/bin:$PATH at the end.
I wouldn't uninstall it since many scripts will expect python to be in the usual places when they do not follow convention and use #!/usr/bin/env python. You should simply edit your .profile or .bash_profile so the macports binaries are the first in your path.
Your .profile should have this line:
export PATH=/opt/local/bin:/opt/local/sbin:$PATH
If not, add it in, and now your shell will search macport's bin/ first, and should find macports python before system python.
The current Macports installer does the .profile PATH modification automatically.

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