git gui not working after installing in Mac (e.g. Mountain Lion)

Seems like in mid-2021 all answers got obsolete (even mine!), so here's my new answer:

brew install git-gui || brew upgrade git-gui
git gui || /usr/local/opt/git/bin/git gui

OLD ANSWER: Seems like in late 2017 all answers above got obsolete, so here's my new answer:

brew install git || brew upgrade git
git gui || /usr/local/opt/git/bin/git gui

This post: http://www.cmsimike.com/blog/2012/07/30/git-gui-and-osx-mountain-lion/ saves me.

Edit ~/.bash_profile and put in

alias gui='/usr/local/git/libexec/git-core/git-gui'

Now the new command is gui instead of git gui.

EDIT (28 Jan 2013)

I have found a better answer to why git gui wasn't working: Did Apple remove the 'git gui' command in XCode 4.5 command line tools?. Please refer to this solution instead.

Apple did indeed remove the 'git gui' command. I decided to just homebrew git instead of relying on the XCode command line tools.

brew install git

Then I edited the /etc/paths file to have the /usr/local/bin directory come before the /usr/bin directory, because that wasn't right either. Then exited the terminal window and restarted, and now I get:

$ which git
/usr/local/bin/git

$ git --version
git version 1.7.12.1

and the git gui command works again.

EDIT (2020-02-03)

As of version 2.25.0_1, git gui is now provided by a separate formula in brew, named git-gui. See the following PR and issues for the background to this change: https://github.com/Homebrew/homebrew-core/pull/49136

So along with installing Homebrew's git, to have access to git gui one must run

brew install git-gui

Edit your git config to an add an entry for gui in the alias section

nano ~/.gitconfig

[alias]

gui = !sh -c '/usr/local/git/libexec/git-core/git-gui'

Edit 2020

It looks like the path in the original answer is now obsolete. Updated instructions:

[alias]

gui = !sh -c '/usr/local/opt/git/bin/git gui'