MacOS – How to fix git path after MacOS Sierra update

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.

.zshrc is a file run when you start an interactive zsh shell, found in your home directory. The error message says you have an export command which is written incorrectly on line 48. not valid in this context means you're trying to export something that's not a variable. It looks like you're trying to add stuff to your PATH, but are substituting the current path inside the zshrc file. Check that line in the file, there's probably a line along the lines of:

export $PATH=/some/directory/to/add/to/path/:$PATH

You just need to remove the first $ because it's substituting the current path there instead of assigning the PATH variable:

export PATH=/some/directory/to/add/to/path/:$PATH

See https://stackoverflow.com/questions/22394367/zsh-error-export54-not-valid-in-this-context