I have some custom modules that are generated using SWIG that are installed in a a local path eg:


When I try to run a python script that uses one of these modules, I get an import error:

"/usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python2.7/importlib/__init__.py", line 37, in import_module
ImportError: No module named _mag_manip

I've figured out that this is due to the shebang at the top of the python script:

#!/usr/bin/env python

Because /usr/bin/env is protected by System Integrity Protection (SIP), the DYLD_LIBRARY_PATH environment variable is not loaded and some modules cannot be found. A fix is to replace the shebang with the hardcoded path of python ie:


Since my code runs on Linux and Mac OSX, replacing the normal python shebang with a hardcoded path on mac is not a really good solution. Does anybody know what the best solution is here?

  • 1
    Isn't the issue that DYLD_LIBRARY_PATH should better not be used anymore? This certainly refers to how the package was built and how the linking parameters were set. This illuminative SO answer helped me a lot to understand related issues.
    – normanius
    Dec 7, 2017 at 23:33

1 Answer 1


Note: This only works in the Z shell (zsh).

Although I would normally say this is a bad idea, I can't see anything wrong with doing this with env, which is a pretty harmless command. Try copying env into /usr/local/bin and replacing /usr/bin/env python in the shebang with just env python (without the absolute path). Assuming you have /usr/local/bin somewhere near the beginning of your PATH variable on OS X, it'll pick up the relocated one, which will no longer be covered under SIP. That shebang will also work on Linux.

  • Don't think that works because if I just put env in the shebang, I get: env: bad interpreter: No such file or directory Jun 9, 2017 at 13:50
  • Sorry, I meant env python. Jun 9, 2017 at 18:21
  • That works in zsh but barfs in ksh and bash.
    – fd0
    Jun 9, 2017 at 18:29
  • 1
    Oh my, I had completely forgotten about the behavior of BASH. Whoops. ZSH really is so much more convenient, for this and countless other reasons. In any case, I'll leave this up for Z-Shell users. Jun 9, 2017 at 18:34

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