(optional) add these to ~/.bashrc:
PIP_REQUIRE_VIRTUALENV=true
PIP_RESPECT_VIRTUALENV=true
1. install system-level virtualenv
sudo aptitude install virtualenv
2. use it to create a clean "distribution" centered around a private Python executable and your own packaged scripts
virtualenv --no-site-packages --distribute ENV
3. activate it for this shell
. ENV/bin/activate
This modifies the local PATH, so now "python" is your private one. Add/remove packages to your heart's content without messing with the system-global one.
which pip # /home/johnm/work/ex-package/ENV/bin/pip
4. verify by installing a package from the internet
pip install coverage python -c 'import coverage'
5. verify by installing a local package
pip -v install Mypackage-0.1dev.tar.gz python -c 'import mypackage'