MacOS – How to get git update-index working with macOS

git is installed by Xcode. I doubt you'll have any problems if you replace it, but I can't give you a definitive answer to that…

1. What I'd do is rename the old /usr/bin/git to git_old, then rely on your path to select the new one.
2. If that doesn't work, move the new one to /usr/bin. I doubt Xcode is picky about which version of git it's using.
3. If that still doesn't work, move git_old back to /usr/bin/git and use either a direct path, rename, or alias for your new one.

I doubt you'll have to go past #1 above, though. That should be enough.

Edit: I read your original post backwards. The first thing you should do is make sure your path includes the new git directory BEFORE the directory that contains the old git.

Seems that you have problems connecting to github via https.

While I'm not sure what could cause it and how to fix it, you still can use git with another protocol.

Here's the commands to install homebrew in /usr/local/ from scratch using git:// instead of https://:

cd /usr/local/
git init -q
git remote add origin git://github.com/mxcl/homebrew
git fetch origin master:refs/remotes/origin/master -n
git reset --hard origin/master

That should work. Please notice that if you choose to use another directory for homebrew, you probably will have to append its ./bin directory to your environment PATH variable for comfortable usage.