Why Is Pip Freeze Not Showing A Module Although Pip Install Says It's Already Installed

I'm following these instructions to install odoo on mac. It required that I install all the python modules for the user like so: $ sudo pip install -—user -r requirements.txt (*

Solution 1:

inspired by dsgdfg's comment.. I simply followed installation instructions here.. and it worked just fine

update

the above isn't much a solution, b/c i had to go back and install every library mentioned in requirements.txt manually!! i just created a virtual env and it ran without a hitch from first attempt!