How to activate virtualenv in Linux?

Here is my workflow after creating a folder and cd'ing into it:

$ virtualenv venv --distribute
New python executable in venv/bin/python
Installing distribute.........done.
Installing pip................done.
$ source venv/bin/activate
(venv)$ python

You forgot to do source bin/activate where source is a executable name. Struck me first few times as well, easy to think that manual is telling "execute this from root of the environment folder".

No need to make activate executable via chmod.

You can do

source ./python_env/bin/activate

or just go to the directory

cd /python_env/bin/

and then

source ./activate

Good Luck.