virtualenv is a tool to create isolated Python environments.
Virtual Python Environment builder ================================== `virtualenv` is a tool to create isolated Python environments. Virtualenv is probably what you want to use during development, and in production too if you have shell access there. What problem does Virtualenv solve? If you like Python as I do, chances are you want to use it for other projects besides [Werkzeug-based web applications](http://werkzeug.pocoo.org). But the more projects you have, the more likely it is that you will be working with different versions of Python itself, or at least different versions of Python libraries. Let's face it; quite often libraries break backwards compatibility, and it's unlikely that any serious application will have zero dependencies. So what do you do if two or more of your projects have conflicting dependencies? Virtualenv to the rescue! It basically enables multiple side-by-side installations of Python, one for each project. It doesn't actually install separate copies of Python, but it does provide a clever way to keep different project environments isolated. So let's see how virtualenv works! If you are on *Mac OSX* or *Linux*, chances are that one of the following two commands will work for you: $ sudo easy_install virtualenv or even better: $ sudo pip install virtualenv One of these will probably install virtualenv on your system. Maybe it's even in your package manager. If you use Ubuntu, try: $ sudo apt-get install python-virtualenv If you are on Windows and don't have the `easy_install` command, you must install it first. Once you have it installed, run the same commands as above, but without the `sudo` prefix. Once you have virtualenv installed, just fire up a shell and create your own environment. I usually create a project folder and an env folder within: $ mkdir myproject $ cd myproject $ virtualenv env New python executable in env/bin/python Installing setuptools............done. Now, whenever you want to work on a project, you only have to activate the corresponding environment. On OS X and Linux, do the following: $ . env/bin/activate > **Note** the space between the dot and the script name. The dot means that > this script should run in the context of the current shell. If this > command does not work in your shell, try replacing the `.` with `source`. If you are a Windows user, the following command is for you: $ env\scripts\activate Either way, you should now be using your virtualenv (see how the prompt of your shell has changed to show the virtualenv). Now you can just enter the following command to get Werkzeug activated in your virtualenv: A few seconds later you are good to go. --- **Source** - [_Werkzeug_](http://werkzeug.pocoo.org/docs/installation/#virtualenv) Installation Guide **Additional Resources** - [Virtualenv Python Package Index](https://pypi.python.org/pypi/virtualenv)