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issues with python virtual environment

I am facing following 2 issues:
python command is not using the virtualenvwrapper python.
After activating my virtual environment if I type python then the code still uses the native python libraries. I can easily install libraries etc with pip to my virtual environment but I cannot run any command using python.
e.g. if I execute $ ./manage.py runserverthen it is fine and I can run a django server
but if I try $ python manage.py runserver
or even just
$ python
then it uses the native python libraries and that should not happen
This is while using iterm or terminal in osx. I have never faced this problem in any linux based os
While using any os (linux based or osx), the workon command doesn't work inside any shell script, while it works normally in a terminal
os: osx

sounds like Python might be using the packages in site-packages, which means you should use the --no-site-packages flag when creating your virtualenv (although it seems like this is the default in the current version of virtualenv).
In order to access the virtualenvwrapper functions from a shell script, you will first need to source it: $ source /usr/local/bin/virtualenvwrapper.sh (the path might be different in your case).

You could try install virtualenv and virtualenvwrapper from pip3.
pip3 install virtualenv virtualenvwrapper
And then find where virtualenvwrapper.sh file is:
find / -name 'virualenvwrapper.sh'
I have mine in /usr/local/bin/virtualenvwrapper.sh. But it seems that you have it in some different directory. So you must change below config to fit your needs.
And then in your .bashrc or .zshrc:
# Python3 virtualenv/venvwrapper
export WORKON_HOME=~/.virtualenvs
VIRTUALENVWRAPPER_PYTHON='/usr/bin/python3' # This needs to be placed before the virtualenvwrapper command
export PROJECT_HOME=$HOME/Projects
source /usr/local/bin/virtualenvwrapper.sh # your path to virtualenvwrapper.sh
Let me know if it works :)

pip installs packages successfully, but executables not found from command line

I am working on mac OS X Yosemite, version 10.10.3.
I installed python2.7 and pip using macport as done in
http://johnlaudun.org/20150512-installing-and-setting-pip-with-macports/
I can successfully install packages and import them inside my python environment and python scripts. However any executable associated with a package that can be called from the command line in the terminal are not found.
Does anyone know what might be wrong? (More details below)
For example while installing a package called "rosdep" as instructed in http://wiki.ros.org/jade/Installation/Source
I can run: sudo pip install -U rosdep
which installs without errors and corresponding files are located in /opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages
However if I try to run : sudo rosdep init,
it gives an error : "sudo: rosdep: command not found"
This is not a package specific error. I get this for any package installed using pip on my computer. I even tried adding
/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages
to my $PATH.
But the executables are not found on the command line, even though the packages work perfectly from within python.

I know the question asks about macOS, but here is a solution for Linux users who arrive here via Google.
I was having the issue described in this question, having installed the pdfx package via pip.
When I ran it however, nothing...
pip list | grep pdfx
pdfx (1.3.0)
Yet:
which pdfx
pdfx not found
The problem on Linux is that pip install ... drops scripts into ~/.local/bin and this is not on the default Debian/Ubuntu $PATH.
Here's a GitHub issue going into more detail: https://github.com/pypa/pip/issues/3813
To fix, just add ~/.local/bin to your $PATH, for example by adding the following line to your .bashrc file:
export PATH="$HOME/.local/bin:$PATH"
After that, restart your shell and things should work as expected.

Solution
Based on other answers, for linux and mac you can run the following:
echo "export PATH=\"`python3 -m site --user-base`/bin:\$PATH\"" >> ~/.bashrc
source ~/.bashrc
instead of python3 you can use any other link to python version: python, python2.7, python3.6, python3.9, etc.
instead of .bashrc, choose the rc file from your favourite shell.
Explanation
In order to know where the user packages are installed in the current OS (win, mac, linux), we run:
python3 -m site --user-base
We know that the scripts go to the bin/ folder where the packages are installed.
So we concatenate the paths:
echo `python3 -m site --user-base`/bin
Then we export that to an environment variable.
export PATH=\"`python3 -m site --user-base`/bin:\$PATH\"
Finally, in order to avoid repeating the export command we add it to our .bashrc file and we run source to run the new changes, giving us the suggested solution mentioned at the beginning.

On macOS with the default python installation you need to add /Users/<you>/Library/Python/2.7/bin/ to your $PATH.
Add this to your .bash_profile:
export PATH="/Users/<you>/Library/Python/2.7/bin:$PATH"
That's where pip installs the executables.
Tip: For non-default python version which python to find the location of your python installation and replace that portion in the path above. (Thanks for the hint Sanket_Diwale)

check your $PATH
tox has a command line mode:
audrey:tests jluc$ pip list | grep tox
tox (2.3.1)
where is it?
(edit: the 2.7 stuff doesn't matter much here, sub in any 3.x and pip's behaving pretty much the same way)
audrey:tests jluc$ which tox
/opt/local/Library/Frameworks/Python.framework/Versions/2.7/bin/tox
and what's in my $PATH?
audrey:tests jluc$ echo $PATH
/opt/chefdk/bin:/opt/chefdk/embedded/bin:/opt/local/bin:..../opt/local/Library/Frameworks/Python.framework/Versions/2.7/bin...
Notice the /opt/local/Library/Frameworks/Python.framework/Versions/2.7/bin? That's what allows finding my pip-installed stuff
Now, to see where things are from Python, try doing this (substitute rosdep for tox).
$python
>>> import tox
>>> tox.__file__
that prints out:
'/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/tox/__init__.pyc'
Now, cd to the directory right above lib in the above. Do you see a bin directory? Do you see rosdep in that bin? If so try adding the bin to your $PATH.
audrey:2.7 jluc$ cd /opt/local/Library/Frameworks/Python.framework/Versions/2.7
audrey:2.7 jluc$ ls -1
output:
Headers
Python
Resources
bin
include
lib
man
share

If you're installing using --user (e.g. pip3.6 install --user tmuxp), it is possible to get the platform-specific user install directory from Python itself using the site module. For example, on macOS:
$ python2.7 -m site --user-base
/Users/alexp/Library/Python/2.7
By appending /bin to this, we now have the path where package executables will be installed. We can dynamically populate the PATH in your shell's rc file based on the output; I'm using bash, but with any luck this is portable:
# Add Python bin directories to path
python3.6 -m site &> /dev/null && PATH="$PATH:`python3.6 -m site --user-base`/bin"
python2.7 -m site &> /dev/null && PATH="$PATH:`python2.7 -m site --user-base`/bin"
I use the precise Python versions to reduce the chance of the executables just "disappearing" when Python upgrades a minor version, e.g. from 3.5 to 3.6. They'll disappear because, as can be seen above, the user installation path may include the Python version. So while python3 could point to 3.5 or 3.6, python3.6 will always point to 3.6. This needs to be kept in mind when installing further packages, e.g. use pip3.6 over pip3.
If you don't mind the idea of packages disappearing, you can use python2 and python3 instead:
# Add Python bin directories to path
# Note: When Python is upgraded, packages may need to be re-installed
# or Python versions managed.
python3 -m site &> /dev/null && PATH="$PATH:`python3 -m site --user-base`/bin"
python2 -m site &> /dev/null && PATH="$PATH:`python2 -m site --user-base`/bin"

The Installing Packages tutorial on python.org describes how to locate the binary directory:
On Windows
You can find the user base binary directory by running
python -m site --user-site and replacing site-packages with Scripts.
For example, this could return
C:\Users\Username\AppData\Roaming\Python36\site-packages so you
would need to set your PATH to include
C:\Users\Username\AppData\Roaming\Python36\Scripts.
On Linux and macOS
On Linux and macOS you can find the user base binary directory by
running python -m site --user-base and adding bin to the end. For
example, this will typically print ~/.local (with ~ expanded to the
absolute path to your home directory) so you’ll need to add
~/.local/bin to your PATH.

I stumbled upon this question because I created, successfully built and published a PyPI Package, but couldn't execute it after installation. The $PATHvariable was correctly set.
In my case the problem was that I hadn't set the entry_pointin the setup.py file:
entry_points = {'console_scripts':
['YOUR_CONSOLE_COMMAND=MODULE_NAME.FILE_NAME:FUNCTION_NAME'],},

On Windows, you need to add the path %USERPROFILE%\AppData\Roaming\Python\Scripts to your path.

Windows and Python 3.9 from MS Store
I have a different path with python -m site --user-base and python -m site - yes, the second command without --user-base to get all sites - as the other answers here state:
C:\Users\<your User>\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages
Why is my path different
Because I installed python from MS Store
Solution
Put the above path in your path and replace site-packages with scripts

When you install Python or Python3 using MacOS installer (downloaded from Python website) - it adds an exporter to your ~/.profile script. All you need to do is just source it. Restarting all the terminals should also do the trick.
WARNING - I believe it's better to just use pip3 with Python3 - for future benefits.
If you already have Python3 installed, the following steps work for me on macOS Mojave:
Install ansible first using sudo - sudo -H pip3 install ansible
you create a symlink to the Python's bin path
sudo ln -s /Library/Frameworks/Python.framework/Versions/Current/bin /Library/Frameworks/Python.framework/current_python_bin
and staple it to .profile
export PATH=$PATH:/Library/Frameworks/Python.framework/current_python_bin
run source ~/.profile and restart all terminal shells.
Type ansible --version

In addition to adding python's bin directory to $PATH variable, I also had to change the owner of that directory, to make it work. No idea why I wasn't the owner already.
chown -R ~/Library/Python/

I solve the problem!
Use pip3 instead pip.
pip3 install foobaz
vim ~/.zshrc and add:
export PATH="/Users/your_name/Library/Python/3.8/bin:$PATH"
source ~/.zshrc
Now MacOS has shifted the default terminal from bash to zsh. Therefore, you have to source zshrc but not bashrc or bash_profile.
foobaz -v

had the same issue with macOS Monterey. I had to modify my .bash_profile file and add the following entry
export PATH="~/Library/Python/3.8/bin:$PATH"
The default python version on macOS Monterey is 3.8, but you will have to double check your python version to make sure you're using the correct one

pip: Could not find an activated virtualenv (required)

I am trying to instal virtualenv and/or virtualenvwrapper on a Mac OS X 10.8.3.
I have been fighting with python for the last two days. Finally I was able to install Python 2.7.4 using brew. Before I had virtualenv installed using easy_install. Then I tried to uninstall it, trying to get my computer in the same situation as the one of my colleagues. Maybe I uninstalled it with success, maybe not. I don't know how to test it. Now I am supposed to install virtualenv using:
pip install virtualenv
But it gives me:
Could not find an activated virtualenv (required).
pip install virtualenvwrapper gives exactly the same output.
Also the variable: PIP_RESPECT_VIRTUALENV is null:
echo $PIP_RESPECT_VIRTUALENV
How can I solve this issue?

Open your ~/.bashrc file and see if this line is there -
export PIP_REQUIRE_VIRTUALENV=true
It might be causing the trouble. If it's there, change it to false and run -
source ~/.bashrc
If not, run export PIP_REQUIRE_VIRTUALENV=false from terminal.
Note: everything works the same if you have .bash_profile instead of .bashrc in your current user's root directory.

#Bibhas has it; +1 to look for export PIP_REQUIRE_VIRTUALENV=true in ~/.profile or ~/.bashrc. You can confirm the setting in your current shell with env |grep PIP_REQUIRE_VIRTUALENV.
This setting is a good safety check; more often than not, you'll want to be installing things into virtualenvs. However, sometimes you do want to be working with the global/system python. In those cases, take a look at --isolated:
Run pip in an isolated mode, ignoring environment variables and user configuration.
$ pip install --upgrade pip
Could not find an activated virtualenv (required).
$ pip install --upgrade pip --isolated
Requirement already up-to-date: pip in /usr/local/lib/python2.7/site-packages
$ pip freeze --isolated
...

An additional solution to those already presented is to add a shell command that will allow you to install py packages by temporarily overriding the default setting. Add this to your ~/.profile, ~/.bashrc or wherever you maintain your shell's exports/settings (in my case, ~/.zshrc).
syspip(){
PIP_REQUIRE_VIRTUALENV="" pip "$#"
}
With this simple addition, you can install pip packages to the system via syspip install <package>.

Verify contents of ~/.pip/pip.conf like:
[global]
index=https://pypi.python.org/simple/
require-virtualenv=false
if previous it was set like require-virtualenv=true

Another place where you may possibly have this "lock" is the pip.conf file. In my case I had one in my ~/Library/Application Support/pip folder and forgot about it.
Typical content of the file could be:
[install]
require-virtualenv = true
[uninstall]
require-virtualenv = true
Similar to other answers, false should be changed to true in the file.

Important to heed #JCotton's advice here-- keeping your pip setup so as to only install into virtualenvs is a great practice.
His solution to get virtualenv setup again of pip install --upgrade pip --isolated is exactly what should be done.
You should NOT turn off requiring a virtualenv, either by config file or by editing ~/.bash_rc or ~/.bash_profile, to get your project's pip packages installed. We're only doing it here because OP needs virtualenv itself installed.
In general, I see people get this message when their virtualenv wasn't setup correctly for their project in the first place. Reminder that to create a virtualenv with its own python and pip so that you don't run into the "could not find an activated virtualenv" error, you run virtualenv -p python3

for matchbook you must go to '.bash_profile '
1) open with your favorite editor in terminal
nano .bash_profile OR vim .bash_profile
2) find the text line that says
export PIP_REQUIRE_VIRTUALENV=true
3) delete it or set it equal to "false"
4) finally restart your terminal

Why do distribute and pip install to my virtualenv's ./local/bin?

I create and activate a virtualenv (venv) using Python 3.3's built-in way of doing it:
$ python3.3 -m venv env
$ source env/bin/activate
At this point python is the python in my virtualenv, which I expect:
(env) $ which python
/my_home_directory/env/bin/python
Now I want to install distribute and pip, so I download the setup scripts and run them:
(env)$ wget http://python-distribute.org/distribute_setup.py
(env)$ wget https://raw.github.com/pypa/pip/master/contrib/get-pip.py
(env)$ python distribute_setup.py
(env)$ python get-pip.py
These commands complete successfully. At this point I inspect my venv to find another directory called "local" which wasn't there before. env/local/bin contains my easy_install and pip executables, and they're still aliased to my system's existing easy_install and pip:
(env)$ ls env
bin include lib local pyvenv.cfg
(env)$ ls env/bin
activate pydoc python python3 python3.3
(env)$ ls env/local/bin
easy_install easy_install-3.3 pip pip-3.3
(env)$ which easy_install
/usr/bin/easy_install
(env)$ which pip
/usr/bin/pip
I believe this is a departure from Python 2.x's behavior. At this point I expect easy_install and pip to be using the virtualenv's copies, and using them to install eggs will put them in the virtualenv.
Going a bit further, I crack open env/bin/activate to find that env/bin is prepended to the system path, but env/local/bin is not. That explains the behavior I'm seeing. I can work around this problem by editing env/bin/activate to add the env/local/bin directory to the path, something like:
_OLD_VIRTUAL_PATH="$PATH"
PATH="$VIRTUAL_ENV/bin:$PATH"
PATH="$VIRTUAL_ENV/local/bin:$PATH" # my new line
export PATH
So, what's going on here? Is this a bug, or am I missing something?
I'm on Ubuntu 12.10 in case that makes a difference.

I have a feeling there's a bug in Ubuntu's python packages or distribute somewhere… but I haven't tracked it down (and I'm not sure I care to).
For whatever reason, the VIRTUAL_ENV environment variable needs to be set the root of the virtualenv for distribute and pip to install properly.
This gist, adopted from Vinay Sajip's code sample in the Python 3 docs, sets said variable; both distribute and pip will install properly when using it.

It's in the python docs.
'/usr/local' is the default exec_prefix. Read the venv docs for detail how to change the default behaviour. There's even an example there that shows how to make a venv.EnvBuilder that installs distribute and pip for you.
if you find distribute docs, please let me know ;-)

I had the same problem.
In activate script file I need to add as first line (of cource after #!...):
unset PYTHON_PATH

Why does pip installs a package outside my virtual environment?

After doing a source of the virtual environment I try
pip install -U --no-deps django-social-auth
and it returns:
OSError: [Errno 13] Permission denied: '/usr/local/lib/python2.6/dist-packages/django_social_auth-0.6.9-py2.6.egg-info/dependency_links.txt'
Why is it trying to write outside the virtualenv?

I ran into this problem when I renamed the directory containing my virtual environment. The hard path pip was using was no longer correct.
Update the shebang in the pip script to point to your virtual environment's python executable.

In my opinion, either you are executing a pip that is not part of the virtualenv, or you are, but the python interpreter that gets executed is not part of the virtualenv. Check if the pip you are executing is the right one with which pip, and force the python from the virtualenv by using your_envdir/bin/python pip <arguments>, instead of just invoking plain pip.
This is strange, because if you correctly activated the environment with bin/activate, you should get the correct pip. Are you sure you activated with . bin/activate, and not sh bin/activate ? They are two different things. Did the prompt change ?

you should probably make sure that you the pip from you virtual environment, so sth. like
./env/bin/pip install -U --no-deps django-social-auth

I ran into this problem when I had mistakingly set PYTHONPATH incorrectly in ~/.bashrc. If echo $PYTHONPATH returns anything outside your expected environment, delete it with export PYTHONPATH='' and check your ~/.bashrc for PYTHONPATH.