在OS X 10.8.1上设置Python和Virtualenv？

Question

I recently reinstalled my OS X and my python setup is gone with it. I can't remember how I set it up before and now I am having a lot of trouble. I followed this guide (http://www.thisisthegreenroom.com/2011/installing-python-numpy-scipy-matplotlib-and-ipython-on-lion/#python) up to the part that makes a sym link. (CTRL+F this in the webpage: "ln -s /usr/local/Cellar/python/2.7.2/Frameworks/Python.framework/Versions/Current")

It didn't produce "/usr/local/bin/python" when I put in "which python". Instead, it gave me "/usr/bin/python".

What am I doing wrong? This is so frustrating! How can I fix this, or is there a better step by step tutorial that allows me to install python via Homebrew and then install virtualenv on top of that python installation?

Answer 1

FINALLY SOLVED IT!

the PATH variable has a short circuit logic to it. It goes down each variable(folder locations like "/etc/paths", "~/.profile", etc). When it finds your command ("python") in the folder it is looking at, that's what the terminal gives you.

To solve my problem, you have to put "/usr/local/bin"(where the homebrew python installation is) ahead of "/usr/bin"(where the default OS X python installation is.). To do this, open "/etc/paths" in terminal with:

open /etc/paths

this will open up the "paths" file in your default text editor. Now it should look something like this:

/usr/bin
/bin
/usr/sbin
/sbin
/usr/local/bin

Since the file is in a protected folder, its not going to let you edit it directly. When you edit the file, it will ask to make a duplicate.

Save the duplicate to desktop, and move "/usr/local/bin" to the top, like this:

/usr/local/bin
/usr/bin
/bin
/usr/sbin
/sbin

Remove the actual file("/etc/paths") and copy your duplicate file from the desktop. Be sure to remove the .txt extension on the duplicate. If you are not sure how to do this, go to Finder > Preferences > Advanced and check Show all filename extensions. Rename the file to "paths"

Log out and log back in to refresh it and you are done!