virtualenv cloning script.

A script for cloning a non-relocatable virtualenv.

Virtualenv provides a way to make virtualenv's relocatable which could then be copied as we wanted. However making a virtualenv relocatable this way breaks the no-site-packages isolation of the virtualenv as well as other aspects that come with relative paths and /usr/bin/env shebangs that may be undesirable.

Also, the .pth and .egg-link rewriting doesn't seem to work as intended. This attempts to overcome these issues and provide a way to easily clone an existing virtualenv.

It performs the following:

• copies sys.argv[1] dir to sys.argv[2]

• updates the hardcoded VIRTUAL_ENV variable in the activate script to the new repo location. (--relocatable doesn't touch this)

• updates the shebangs of the various scripts in bin to the new Python if they pointed to the old Python. (version numbering is retained.)

  it can also change /usr/bin/env python shebangs to be absolute too, though this functionality is not exposed at present.

• checks sys.path of the cloned virtualenv and if any of the paths are from the old environment it finds any .pth or .egg link files within sys.path located in the new environment and makes sure any absolute paths to the old environment are updated to the new environment.

• finally it double checks sys.path again and will fail if there are still paths from the old environment present.

NOTE: This script requires Python 2.7 or 3.4+