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I recently switched from bash to zsh (MacOS). I haven't used pipenv since the switch. Now when I run any pipenv command I get the following error:
$ pipenv install
zsh: /usr/local/bin/pipenv: bad interpreter: /usr/local/opt/python/bin/python3.7: no such file or directory
I use pyenv for Python dependency management:
$ which python
/Users/ryan.payne/.pyenv/shims/python
My default python version is 3.7.3:
$ pyenv versions
system
2.7.16
3.6.8
* 3.7.3 (set by /Users/ryan.payne/.pyenv/version)
It seems like pipenv is not using my pyenv version of Python. How do I get pipenv working again?
You don't need to uninstall anything. Simply change the interpreter at /usr/local/bin and have your current python path in pyenv handy:
type python3
copy the path
vi /usr/local/bin/pipenv
It will look something like this:
Once it's changed, you will probably have to download pipenv again. Don't worry, your env is fine.
pip install pipenv
Go play in your env
I had this same error with awscli. The solution was to install python#3.7 via homebrew and then cp that installation into the directory awscli expected.
brew install python#3.7
cp -r /usr/local/opt/python#3.7/bin/python3.7 /usr/local/opt/python/bin/python3.7
Run in terminal:
brew install python3 && cp /usr/local/bin/python3 /usr/local/bin/python
After brew installation, sometimes it may not work.
Depending on whether you tried to install other python versions, the links might not be working any more, and therefore running the command
brew install python3 && cp /usr/local/bin/python3 /usr/local/bin/python
Might give an error as below
Error: Could not symlink bin/2to3
Target /usr/local/bin/2to3
already exists.
Try to remove the file 2to3
rm '/usr/local/bin/2to3'
and run the above code again
Alternatively, you can force the linkage
brew link --overwrite python#<version>
but you can first see the files that will be deleted by this forced linking using the command
brew link --overwrite --dry-run python#<version>
I hope this gives more light
If you installed pipenv with pipenv with pipx, then you can reinstall pipenv via pipx reinstall pipenv which should detect any top level changes in your python environment.
I'm working in Amazon's Cloud9.
ec2-user:~/environment/flask_init $ python -V
Python 2.7.14
ec2-user:~/environment/flask_init $ virtualenv -p python3 venv
Running virtualenv with interpreter /usr/bin/python3
Using base prefix '/usr'
New python executable in /home/ec2-user/environment/flask_init/venv/bin/python3
Also creating executable in /home/ec2-user/environment/flask_init/venv/bin/python
Installing setuptools, pip, wheel...done.
ec2-user:~/environment/flask_init $ source venv/bin/activate
(venv) ec2-user:~/environment/flask_init $ python -V
Python 2.7.14
Why is the virtual environment not using Python 3?
Please note that this question is not a duplicate of this one. The issue was specifically to do with the way the Cloud 9 environment sets up Python alias.
I tried your flow on my machine and everything works as expected.
dluzak#Karol-PC:/tmp$ python -V
Python 2.7.12
dluzak#Karol-PC:/tmp$ virtualenv -p python3 venv
Already using interpreter /usr/bin/python3
Using base prefix '/usr'
New python executable in /tmp/venv/bin/python3
Also creating executable in /tmp/venv/bin/python
Installing setuptools, pkg_resources, pip, wheel...done.
dluzak#Karol-PC:/tmp$ source venv/bin/activate
(venv) dluzak#Karol-PC:/tmp$ python -V
Python 3.5.2
(venv) dluzak#Karol-PC:/tmp$
Nonetheless I personally use virtualenv as module when creating venv with python 3: python3 -m virtualenv venv. Maybe this would work.
You provided very little details. Have you installed virtualenv for both Python 2 and 3? Are you sure Python 3 interpreter works fine?
Edit:
After investigation in comments we found out that the problem was in bash settings configured by Amazon. It seams that Amazon configures bash (probably in ~/.bashrc) to replace python calls with an alias. To fix this a call unalias python before enabling venv is needed. It is described in Amazon docs
When I was using virtualenv earlier today, I had the same problem that my env was not using the right version of python.
Instead of activating my environment like this:
source activate
I found that activating it like this actually worked:
source ./activate
Hope this is helpful!
Here is how i create virtualenv on Cloud9
Python 3.4
$ sudo pip install virtualenv
$ virtualenv -p /usr/bin/python3.4 venv
$ source venv/bin/activate
Python 3.6
$ sudo apt update
$ sudo apt install python3.6-venv
$ python3.6 -mvenv venv
$ source venv/bin/activate
I have encountered a similar issue.
In my case did not work because I moved the virtual env folder (but the same thing happens when you rename it).
You can understand which version of python (and thus which module will import) is using by typing
$ which python
If it write something like:
/usr/bin/python
Then it means your virtual env is not being activated.
To solve this issue, instead of creating a new virtual environment, you can simply edit the script activation file in your env:
$ nano venv/bin/activate
And edit the following line with your absolute path of your virtual environment:
VIRTUAL_ENV="/YOUR_ABSOLUT/PATH_TO/venv"
Hope it helps
:)
This has been driving me crazy for the past 2 days.
I installed virtualenv on my Macbook using pip install virtualenv.
But when I try to create a new virtualenv using virtualenv venv, I get the error saying "virtualenv : command not found".
I used pip show virtualenv and the location of the installation is "Location: /usr/local/lib/python2.7/site-packages" but I can't figure out where the executable is. I tried dozens other similar looking posts but those solutions do not work for me.
Any ideas what might be going wrong here?
The only workable approach I could figure out (with help from #Gator_Python was to do python -m virtualenv venv. This creates the virtual environment and works as expected.
I have custom python installed and maybe that's why the default approach doesn't work for me.
On macOS Mojave
First check python is in the path.
python --version
Second check pip is installed.
pip --version
If it is not installed.
brew install pip
Third install virtualenv
sudo -H pip install virtualenv
For Python 3
python3 -m virtualenv venv
As mentioned in the comments, you've got the virtualenv module installed properly in the expected environment since python -m venv allows you to create virtualenv's.
The fact that virtualenv is not a recognized command is a result of the virtualenv.py not being in your system PATH and/or not being executable. The root cause could be outdated distutils or setuptools.
You should attempt to locate the virtualenv.py file, ensure it is executable (chmod +x) and that its location is in your system PATH. On my system, virtualenv.py is in the ../Pythonx.x/Scripts folder, but this may be different for you.
Could it be that you are using Anaconda package manager? If so, then it has it's own virtual environment system which you setup as follows:
conda create --name venv
I had the same issue (although on ubuntu), a simple solution is instead of doing pip install virtualenv, you precede the commend with "sudo".
A little inspection reveals the reason behind this fix:
pip install virtualenv tries to put an executable under /usr/local/bin so that it can be invoked from command line, but it failed because only root has write permission to that directory
an alternative is pip install --user virtualenv, here are some further readings 1,2
Had the same problem on Windows. Command not found and can't find the executable in the directory given by pip show.
Fixed it by adding "C:\Users{My User}\AppData\Roaming\Python\Python39\Scripts" to the PATH environment variable.
Install virtualenv from https://pypi.org/project/virtualenv
python -m pip install --user virtualenv
sudo /usr/bin/easy_install virtualenv
I succeded creating manually a link to location/virtualenv.py in /usr/local/bin, naming it virtualenv and adding +x attribute on file
➜ ~ pip show virtualenv
Name: virtualenv
Version: 16.6.0
Summary: Virtual Python Environment builder
Home-page: https://virtualenv.pypa.io/
Author: Ian Bicking
Author-email: ianb#colorstudy.com
License: MIT
Location: /home/prsadev/.local/lib/python2.7/site-packages
Requires:
~ chmod +x /home/prsadev/.local/lib/python2.7/site-packages/virtualenv.py
~ sudo ln -sf /home/prsadev/.local/lib/python2.7/site-packages/virtualenv.py /usr/local/bin/virtualenv
I tried to have virtualenv at a random location & faced the same issue on a UBUNTU machine, when I tried to run my 'venv'. What solved my issue was :-
$virtualenv -p python3 venv
Also,instead of using $activate try :-
$source activate
If you look at the activate script(or $cat activate), you will find the same in comment.
This solved my similar problem!
You need to look online on how to create a virtual environement with python X.X.X (replace x.x.x with your python version)
mine was python 3.4.3 so bellow is how should i deal with it:
sudo python3 -m venv aramisvenv
I use asdf and had to do a reshim after installing virtualenv. asdf reshim
Fixed due to this response
Using virtualenv, I run my projects with the default version of Python (2.7). On one project, I need to use Python 3.4.
I used brew install python3 to install it on my Mac. Now, how do I create a virtualenv that uses the new version?
e.g. sudo virtualenv envPython3
If I try:
virtualenv -p python3 test
I get:
Running virtualenv with interpreter /usr/local/bin/python3
Using base prefix '/usr/local/Cellar/python3/3.4.0_1/Frameworks/Python.framework/Versions/3.4'
New python executable in test/bin/python3.4
Also creating executable in test/bin/python
Failed to import the site module
Traceback (most recent call last):
File "/Users/user/Documents/workspace/test/test/bin/../lib/python3.4/site.py", line 67, in <module>
import os
File "/Users/user/Documents/workspace/test/test/bin/../lib/python3.4/os.py", line 634, in <module>
from _collections_abc import MutableMapping
ImportError: No module named '_collections_abc'
ERROR: The executable test/bin/python3.4 is not functioning
ERROR: It thinks sys.prefix is '/Users/user/Documents/workspace/test' (should be '/Users/user/Documents/workspace/test/test')
ERROR: virtualenv is not compatible with this system or executable
simply run
virtualenv -p python3 envname
Update after OP's edit:
There was a bug in the OP's version of virtualenv, as described here. The problem was fixed by running:
pip install --upgrade virtualenv
Python 3 has a built-in support for virtual environments - venv. It might be better to use that instead. Referring to the docs:
Creation of virtual environments is done by executing the pyvenv
script:
pyvenv /path/to/new/virtual/environment
Update for Python 3.6 and newer:
As pawciobiel correctly comments, pyvenv is deprecated as of Python 3.6 and the new way is:
python3 -m venv /path/to/new/virtual/environment
I'v tried pyenv and it's very handy for switching python versions (global, local in folder or in the virtualenv):
brew install pyenv
then install Python version you want:
pyenv install 3.5.0
and simply create virtualenv with path to needed interpreter version:
virtualenv -p /Users/johnny/.pyenv/versions/3.5.0/bin/python3.5 myenv
That's it, check the version:
. ./myenv/bin/activate && python -V
There are also plugin for pyenv pyenv-virtualenv but it didn't work for me somehow.
Install prerequisites.
sudo apt-get install python3 python3-pip virtualenvwrapper
Create a Python3 based virtual environment. Optionally enable --system-site-packages flag.
mkvirtualenv -p /usr/bin/python3 <venv-name>
Set into the virtual environment.
workon <venv-name>
Install other requirements using pip package manager.
pip install -r requirements.txt
pip install <package_name>
When working on multiple python projects simultaneously it is usually recommended to install common packages like pdbpp globally and then reuse them in virtualenvs.
Using this technique saves a lot of time spent on fetching packages and installing them, apart from consuming minimal disk space and network bandwidth.
sudo -H pip3 -v install pdbpp
mkvirtualenv -p $(which python3) --system-site-packages <venv-name>
Django specific instructions
If there are a lot of system wide python packages then it is recommended to not use --system-site-packages flag especially during development since I have noticed that it slows down Django startup a lot. I presume Django environment initialisation is manually scanning and appending all site packages from the system path which might be the reason. Even python manage.py shell becomes very slow.
Having said that experiment which option works better. Might be safe to just skip --system-site-packages flag for Django projects.
virtualenv --python=/usr/bin/python3 <name of env>
worked for me.
This is all you need, in order to run a virtual environment in python / python3
First if virtualenv not installed, run
pip3 install virtualenv
Now Run:
virtualenv -p python3 <env name> # you can specify full path instead <env_name> to install the files in a different location other than the current location
Sometime the cmd virtualenv fails, if so use this:
python3 -m virtualenv <env_name> # you can specify full path instead <env_name> to install the files in a different location other than the current location
Now activate the virtual env:
source <env_name>/bin/activate
Or:
source `pwd`/<env_name>/bin/activate
Now run
which python
You should see the full path to your dir and <env_name>/bin/python suffix
To exit the virtualenv, run:
deactivate
To troubleshoot Python location got to here
You can specify specific Version of Python while creating environment.
It's mentioned in virtualenv.py
virtualenv --python=python3.5 envname
In some cases this has to be the full path to the executable:
virtualenv --python=/Users/username/.pyenv/versions/3.6.0/bin/python3.6 envname
How -p works
parser.add_option(
'-p', '--python',
dest='python',
metavar='PYTHON_EXE',
help='The Python interpreter to use, e.g., --python=python3.5 will use the python3.5 '
'interpreter to create the new environment. The default is the interpreter that '
'virtualenv was installed with (%s)' % sys.executable)
I had the same ERROR message. tbrisker's solution did not work in my case. Instead this solved the issue:
$ python3 -m venv .env
In addition to the other answers, I recommend checking what instance of virtualenv you are executing:
which virtualenv
If this turns up something in /usr/local/bin, then it is possible - even likely - that you installed virtualenv (possibly using an instance of easy_tools or pip) without using your system's package manager (brew in OP's case). This was my problem.
Years ago - when I was even more ignorant - I had installed virtualenv and it was masking my system's package-provided virtualenv.
After removing this old, broken virtualenv, my problems went away.
The below simple commands can create a virtual env with version 3.5
apt-get install python3-venv
python3.5 -m venv <your env name>
if you want virtual env version as 3.6
python3.6 -m venv <your env name>
Python now comes with its own implementation of virtual environment, by the name of "venv". I would suggest using that, instead of virtualenv.
Quoting from venv - docs,
Deprecated since version 3.6: pyvenv was the recommended tool for
creating virtual environments for Python 3.3 and 3.4, and is
deprecated in Python 3.6.
Changed in version 3.5: The use of venv is now recommended for
creating virtual environments.
For windows, to initiate venv on some project, open cmd:
python -m venv "c:\path\to\myenv"
(Would suggest using double quote around directory path if it contains any spaces. Ex: "C:/My Dox/Spaced Directory/Something")
Once venv is set up, you will see some new folders inside your project directory. One of them would be "Scripts".
To activate or invoke venv you need:
C:\> <venv>\Scripts\activate.bat
You can deactivate a virtual environment by typing “deactivate” in your shell. With this, you are now ready to install your project specific libraries, which will reside under the folder "Lib".
================================ Edit 1 ====================================
The scenario which will be discussed below is not what originally asked, just adding this in case someone use vscode with python extension
In case, you use vs code with its python extension, you might face an issue with its pylint which points to the global installation. In this case, pylint won't be able to see the modules that are installed in your virtual environment and hence will show errors while importing.
Here is a simple method to get past this.
cd Workspace\Scripts
.\Activate.ps1
code .
We are basically activating the environment first and then invoking vs-code so that pylint starts within the environment and can see all local packages.
In python3.6 I tried
python3 -m venv myenv,
as per the documentation, but it was taking so long. So the very simple and quick command is
python -m venv yourenv
It worked for me on python3.6.
On Mac I had to do the following to get it to work.
mkvirtualenv --python=/usr/bin/python3 YourEnvNameHere
If you install python3 (brew install python3) along with virtualenv burrito, you can then do mkvirtualenv -p $(which python3) env_name
Of course, I know virtualenv burrito is just a wrapper, but it has served me well over the years, reducing some learning curves.
virtualenv --python=/usr/local/bin/python3 <VIRTUAL ENV NAME>
this will add python3
path for your virtual enviroment.
It worked for me
virtualenv --no-site-packages --distribute -p /usr/bin/python3 ~/.virtualenvs/py3
For those having troubles while working with Anaconda3 (Python 3).
You could use
conda create -n name_of_your_virtualenv python=python_version
To activate the environment ( Linux, MacOS)
source activate name_of_your_virtualenv
For Windows
activate name_of_your_virtualenv
I tried all the above stuff, it still didn't work. So as a brute force, I just re-installed the anaconda, re-installed the virtualenv... and it worked.
Amans-MacBook-Pro:~ amanmadan$ pip install virtualenv
You are using pip version 6.1.1, however version 8.1.2 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
Collecting virtualenv
Downloading virtualenv-15.0.3-py2.py3-none-any.whl (3.5MB)
100% |████████████████████████████████| 3.5MB 114kB/s
Installing collected packages: virtualenv
Successfully installed virtualenv-15.0.3
Amans-MacBook-Pro:python amanmadan$ virtualenv my_env
New python executable in /Users/amanmadan/Documents/HadoopStuff/python/my_env/bin/python
Installing setuptools, pip, wheel...done.
Amans-MacBook-Pro:python amanmadan$
I wanted to keep python 2.7.5 as default version on Centos 7 but have python 3.6.1 in a virtual environment running alongside other virtual environments in python 2.x
I found the below link the best solution for the newest python version ( python 3.6.1)
https://www.digitalocean.com/community/tutorial_series/how-to-install-and-set-up-a-local-programming-environment-for-python-3.
It shows the steps for different platforms but the basic steps are
Install python3.x (if not present) for your platform
Install python3.x-devel for your platform
Create virtual environment in python 3.x
(for example $ python3.6 -m venv virenv_test_p3/ )
Activate the testenvironment for python 3.x
(for example source virenv_test_p3/bin/activate)
Install the packages which you want to use in your new python 3 virtual environment and which are supported ( for example pip install Django==1.11.2)
On Windows command line, the following worked for me. First find out where your python executables are located:
where python
This will output the paths to the different python.exe on your system. Here were mine:
C:\Users\carandangc\Anaconda3\python.exe
C:\Python27\python.exe
So for Python3, this was located in the first path for me, so I cd to the root folder of the application where I want to create a virtual environment folder. Then I run the following which includes the path to my Python3 executable, naming my virtual environment 'venv':
virtualenv --python=/Users/carandangc/Anaconda3/python.exe venv
Next, activate the virtual environment:
call venv\Scripts\activate.bat
Finally, install the dependencies for this virtual environment:
pip install -r requirements.txt
This requirements.txt could be populated manually if you know the libraries/modules needed for your application in the virtual environment. If you had the application running in another environment, then you can automatically produce the dependencies by running the following (cd to the application folder in the environment where it is working):
pip freeze > requirements.txt
Then once you have the requirements.txt that you have 'frozen', then you can install the requirements on another machine or clean environment with the following (after cd to the application folder):
pip install -r requirements.txt
To see your python version in the virtual environment, run:
python --version
Then voila...you have your Python3 running in your virtual environment. Output for me:
Python 3.7.2
For those of you who are using pipenv and want to install specific version:
pipenv install --python 3.6
I got the same error due to it being a conflict with miniconda3 install so when you type "which virtualenv" and if you've installed miniconda and it's pointing to that install you can either remove it (if your like me and haven't moved to it yet) or change your environment variable to point to the install you want.
Is there a way to upgrade the version of python used in a virtualenv (e.g. if a bugfix release comes out)?
I could pip freeze --local > requirements.txt, then remove the directory and pip install -r requirements.txt, but this requires a lot of reinstallation of large libraries, for instance, numpy, which I use a lot.
I can see this is an advantage when upgrading from, e.g., 2.6 -> 2.7, but what about 2.7.x -> 2.7.y?
If you happen to be using the venv module that comes with Python 3.3+, it supports an --upgrade option.
Per the docs:
Upgrade the environment directory to use this version of Python, assuming Python has been upgraded in-place
python3 -m venv --upgrade ENV_DIR
Did you see this? If I haven't misunderstand that answer, you may try to create a new virtualenv on top of the old one. You just need to know which python is going to use your virtualenv (you will need to see your virtualenv version).
If your virtualenv is installed with the same python version of the old one and upgrading your virtualenv package is not an option, you may want to read this in order to install a virtualenv with the python version you want.
EDIT
I've tested this approach (the one that create a new virtualenv on top of the old one) and it worked fine for me. I think you may have some problems if you change from python 2.6 to 2.7 or 2.7 to 3.x but if you just upgrade inside the same version (staying at 2.7 as you want) you shouldn't have any problem, as all the packages are held in the same folders for both python versions (2.7.x and 2.7.y packages are inside your_env/lib/python2.7/).
If you change your virtualenv python version, you will need to install all your packages again for that version (or just link the packages you need into the new version packages folder, i.e: your_env/lib/python_newversion/site-packages)
Updated again:
The following method might not work in newer versions of virtualenv. Before you try to make modifications to the old virtualenv, you should save the dependencies in a requirement file (pip freeze > requirements.txt) and make a backup of it somewhere else. If anything goes wrong, you can still create a new virtualenv and install the old dependencies in it (pip install -r requirements.txt).
Updated: I changed the answer 5 months after I originally answered. The following method is more convenient and robust.
Side effect: it also fixes the Symbol not found: _SSLv2_method exception when you do import ssl in a virtual environment after upgrading Python to v2.7.8.
Notice: Currently, this is for Python 2.7.x only.
If you're using Homebrew Python on OS X, first deactivate all virtualenv, then upgrade Python:
brew update && brew upgrade python
Run the following commands (<EXISTING_ENV_PATH> is path of your virtual environment):
cd <EXISTING_ENV_PATH>
rm .Python
rm bin/pip{,2,2.7}
rm bin/python{,2,2.7}
rm -r include/python2.7
rm lib/python2.7/*
rm -r lib/python2.7/distutils
rm lib/python2.7/site-packages/easy_install.*
rm -r lib/python2.7/site-packages/pip
rm -r lib/python2.7/site-packages/pip-*.dist-info
rm -r lib/python2.7/site-packages/setuptools
rm -r lib/python2.7/site-packages/setuptools-*.dist-info
Finally, re-create your virtual environment:
virtualenv <EXISTING_ENV_PATH>
By doing so, old Python core files and standard libraries (plus setuptools and pip) are removed, while the custom libraries installed in site-packages are preserved and working, as soon as they are in pure Python. Binary libraries may or may not need to be reinstalled to function properly.
This worked for me on 5 virtual environments with Django installed.
BTW, if ./manage.py compilemessages is not working afterwards, try this:
brew install gettext && brew link gettext --force
Step 1: Freeze requirement & take a back-up of existing env
pip freeze > requirements.txt
deactivate
mv env env_old
Step 2: Install Python 3.7 & activate virutal environment
sudo apt-get install python3.7-venv
python3.7 -m venv env
source env/bin/activate
python --version
Step 3: Install requirements
sudo apt-get install python3.7-dev
pip3 install -r requirements.txt
How to upgrade the Python version for an existing virtualenvwrapper project and keep the same name
I'm adding an answer for anyone using Doug Hellmann's excellent virtualenvwrapper specifically since the existing answers didn't do it for me.
Some context:
I work on some projects that are Python 2 and some that are Python 3; while I'd love to use python3 -m venv, it doesn't support Python 2 environments
When I start a new project, I use mkproject which creates the virtual environment, creates an empty project directory, and cds into it
I want to continue using virtualenvwrapper's workon command to activate any project irrespective of Python version
Directions:
Let's say your existing project is named foo and is currently running Python 2 (mkproject -p python2 foo), though the commands are the same whether upgrading from 2.x to 3.x, 3.6.0 to 3.6.1, etc. I'm also assuming you're currently inside the activated virtual environment.
1. Deactivate and remove the old virtual environment:
$ deactivate
$ rmvirtualenv foo
Note that if you've added any custom commands to the hooks (e.g., bin/postactivate) you'd need to save those before removing the environment.
2. Stash the real project in a temp directory:
$ cd ..
$ mv foo foo-tmp
3. Create the new virtual environment (and project dir) and activate:
$ mkproject -p python3 foo
4. Replace the empty generated project dir with real project, change back into project dir:
$ cd ..
$ mv -f foo-tmp foo
$ cdproject
5. Re-install dependencies, confirm new Python version, etc:
$ pip install -r requirements.txt
$ python --version
If this is a common use case, I'll consider opening a PR to add something like $ upgradevirtualenv / $ upgradeproject to virtualenvwrapper.
Let's consider that the environment that one wants to update has the name venv.
1. Backup venv requirements (optional)
First of all, backup the requirements of the virtual environment:
pip freeze > requirements.txt
deactivate
#Move the folder to a new one
mv venv venv_old
2. Install Python
Assuming that one doesn't have sudo access, pyenv is a reliable and fast way to install Python. For that, one should run
curl https://pyenv.run | bash
and then
exec $SHELL
as suggested here.
If, when one tries to update pyenv
pyenv update
and one gets the error
bash: pyenv: command not found
that is because pyenv path wasn't exported to .bashrc. It can be solved by executing the following commands:
echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bashrc
echo 'export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.bashrc
echo -e 'if command -v pyenv 1>/dev/null 2>&1; then\n eval "$(pyenv init -)"\nfi' >> ~/.bashrc
Then restart the shell
exec "$SHELL"
Now one should install the Python version that one wants. Let's say version 3.8.3
pyenv install 3.8.3
One can confirm if it was properly installed by running
pyenv versions
The output should be the location and the versions (in this case 3.8.3)
3. Create the new virtual environment
Finally, with the new Python version installed, create a new virtual environment (let's call it venv)
python3.8 -m venv venv
Activate it
source venv/bin/activate
and install the requirements
pip install -r requirements.txt
Now one should be up and running with a new environment.
I wasn't able to create a new virtualenv on top of the old one. But there are tools in pip which make it much faster to re-install requirements into a brand new venv. Pip can build each of the items in your requirements.txt into a wheel package, and store that in a local cache. When you create a new venv and run pip install in it, pip will automatically use the prebuilt wheels if it finds them. Wheels install much faster than running setup.py for each module.
My ~/.pip/pip.conf looks like this:
[global]
download-cache = /Users/me/.pip/download-cache
find-links =
/Users/me/.pip/wheels/
[wheel]
wheel-dir = /Users/me/.pip/wheels
I install wheel (pip install wheel), then run pip wheel -r requirements.txt. This stores the built wheels in the wheel-dir in my pip.conf.
From then on, any time I pip install any of these requirements, it installs them from the wheels, which is pretty quick.
I just want to clarify, because some of the answers refer to venv and others refer to virtualenv.
Use of the -p or --python flag is supported on virtualenv, but not on venv. If you have more than one Python version and you want to specify which one to create the venv with, do it on the command line, like this:
malikarumi#Tetuoan2:~/Projects$ python3.6 -m venv {path to pre-existing dir you want venv in}
You can of course upgrade with venv as others have pointed out, but that assumes you have already upgraded the Python that was used to create that venv in the first place. You can't upgrade to a Python version you don't already have on your system somewhere, so make sure to get the version you want, first, then make all the venvs you want from it.
This approach always works for me:
# First of all, delete all broken links. Replace my_project_name` to your virtual env name
find ~/.virtualenvs/my_project_name/ -type l -delete
# Then create new links to the current Python version
virtualenv ~/.virtualenvs/my_project_name/
# It's it. Just repeat for each virtualenv located in ~/.virtualenvs
Taken from:
https://github.com/1st/python-on-osx#python-virtualenv
https://gist.github.com/1st/ced02a1c64ac7b82bb27e432eea6b068
If you're using pipenv, I don't know if it's possible to upgrade an environment in place, but at least for minor version upgrades it seems to be smart enough not to rebuild packages from scratch when it creates a new environment. E.g., from 3.6.4 to 3.6.5:
$ pipenv --python 3.6.5 install
Virtualenv already exists!
Removing existing virtualenv…
Creating a v$ pipenv --python 3.6.5 install
Virtualenv already exists!
Removing existing virtualenv…
Creating a virtualenv for this project…
Using /usr/local/bin/python3.6m (3.6.5) to create virtualenv…
⠋Running virtualenv with interpreter /usr/local/bin/python3.6m
Using base prefix '/usr/local/Cellar/python/3.6.5/Frameworks/Python.framework/Versions/3.6'
New python executable in /Users/dmoles/.local/share/virtualenvs/autoscale-aBUhewiD/bin/python3.6
Also creating executable in /Users/dmoles/.local/share/virtualenvs/autoscale-aBUhewiD/bin/python
Installing setuptools, pip, wheel...done.
Virtualenv location: /Users/dmoles/.local/share/virtualenvs/autoscale-aBUhewiD
Installing dependencies from Pipfile.lock (84dd0e)…
🐍 ▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉ 47/47 — 00:00:24
To activate this project's virtualenv, run the following:
$ pipenv shell
$ pipenv shell
Spawning environment shell (/bin/bash). Use 'exit' to leave.
. /Users/dmoles/.local/share/virtualenvs/autoscale-aBUhewiD/bin/activate
bash-3.2$ . /Users/dmoles/.local/share/virtualenvs/autoscale-aBUhewiD/bin/activate
(autoscale-aBUhewiD) bash-3.2$ python
Python 3.6.5 (default, Mar 30 2018, 06:41:53)
[GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.39.2)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import numpy as np
>>>
I moved my home directory from one mac to another (Mountain Lion to Yosemite) and didn't realize about the broken virtualenv until I lost hold of the old laptop. I had the virtualenv point to Python 2.7 installed by brew and since Yosemite came with Python 2.7, I wanted to update my virtualenv to the system python. When I ran virtualenv on top of the existing directory, I was getting OSError: [Errno 17] File exists: '/Users/hdara/bin/python2.7/lib/python2.7/config' error. By trial and error, I worked around this issue by removing a few links and fixing up a few more manually. This is what I finally did (similar to what #Rockalite did, but simpler):
cd <virtualenv-root>
rm lib/python2.7/config
rm lib/python2.7/lib-dynload
rm include/python2.7
rm .Python
cd lib/python2.7
gfind . -type l -xtype l | while read f; do ln -s -f /System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/${f#./} $f; done
After this, I was able to just run virtualenv on top of the existing directory.
On OS X or macOS using Homebrew to install and upgrade Python3 I had to delete symbolic links before python -m venv --upgrade ENV_DIR would work.
I saved the following in upgrade_python3.sh so I would remember how months from now when I need to do it again:
brew upgrade python3
find ~/.virtualenvs/ -type l -delete
find ~/.virtualenvs/ -type d -mindepth 1 -maxdepth 1 -exec python3 -m venv --upgrade "{}" \;
UPDATE: while this seemed to work well at first, when I ran py.test it gave an error. In the end I just re-created the environment from a requirements file.
For everyone with the problem
Error: Command '['/Users/me/Sites/site/venv3/bin/python3', '-Im', 'ensurepip', '--upgrade', '--default-pip']' returned non-zero exit status 1.
You have to install python3.6-venv
sudo apt-get install python3.6-venv