How to Install and activate Virtualenv
1) Install virtualenv
$ sudo apt-get install python-virualenv
2) Create virtual environment for our project
$ virtualenv myenv
virtualenv venv will create a folder in the current directory which will contain the Python executable files. The name of virtualenv is "myenv".
3) To begin using the virtual environment, it needs to be activated
$ source myenv/bin/activate
The name of the current virtual environment will now appear on the left of the prompt.Like this ,
If you want to install any python packages inside the virtual environment then do not use the command: "$ sudo apt-get install packagename".
I am going to show you install python package "django" inside the virtual environment "myenv" using command "$ pip install django" and don't use "$ sudo" command before "$ pip" command:
$ pip install django
4) If you are done working in the virtual environment for the moment, you can deactivate it:
The packages which i am installing into virtual environment "myenv" are stored in "myenv/lib/python2.7/site-packages"