Add to python path mac os x

Modifications to sys.path only apply for the life of that Python interpreter. If you want to do it permanently you need to modify the PYTHONPATH environment variable:

PYTHONPATH="/Me/Documents/mydir:$PYTHONPATH"export PYTHONPATH

Note that PATH is the system path for executables, which is completely separate.

**You can write the above in ~/.bash_profile and the source it using source ~/.bash_profile

Not sure why Matthew's solution didn't work for me (could be that I'm using OSX10.8 or perhaps something to do with macports). But I added the following to the end of the file at ~/.profile

export PYTHONPATH=/path/to/dir:$PYTHONPATH

my directory is now on the pythonpath -

my-macbook:~ aidan$ pythonPython 2.7.2 (default, Jun 20 2012, 16:23:33) [GCC 4.2.1 Compatible Apple Clang 4.0 (tags/Apple/clang-418.0.60)] on darwinType "help", "copyright", "credits" or "license" for more information.>>> import sys>>> sys.path['', '/path/to/dir', ...  

and I can import modules from that directory.

Mathew's answer works for the terminal python shell, but it didn't work for IDLE shell in my case because many versions of python existed before I replaced them all with Python2.7.7.How I solved the problem with IDLE.

1. In terminal, cd /Applications/Python\ 2.7/IDLE.app/Contents/Resources/
2. then sudo nano idlemain.py, enter password if required.
3. after os.chdir(os.path.expanduser('~/Documents')) this line, I added sys.path.append("/Users/admin/Downloads....") NOTE: replace contents of the quotes with the directory where python module to be added
4. to save the change, ctrl+x and enterNow open idle and try to import the python module, no error for me!!!