Adventure with Virtualenv

In the python development world, people are using virtualenv, to isolate their python development environment from their system. Why that is cool,

• You don't conflict with the global python library. Because all new library will be in the isolated environment, on linux many software uses python
• Then you have a fine grain control of what library is needed what is not, for each environment. 
• Because all of the cool pythonista use that...ok that is not quite true, but many python based project strongly recommend using virtualenv, such as turbogears. 
• and some tools are available for this, such as pip. 
• It make it more easier to move project between directory

Lets get started,
here I assume that python setuptools is installed, i assume each project is one environment
to install, just run below as administrator.

easy_install -U virtualenv

 To start a project

virtualenv projectname

This will setup an environment, with their own setuptools.
Let start using it

 source projectname/bin/activate

and it should have the whole python environment there, isolated from the system. including python, their own site-packages

To stop using it

deactivate

To totally isolate from the system, start a new project by

virtualenv --no-site-packages projectname

 It will not use library from the system.

Some tools already begin to support virtualenv. Such as pip, a replacement for easy_install, with uninstall support. To use pip with virtualenv

pip -E projectname packagename

So, virtualenv is now the requirement of most project now. Time to learn it...