Due to the CVE-2016-2324, CVE-2016‑2315, we should upgrade our git client immediatly to prevent remote code execution :p.

In OS X, git comes with XCode Developer tool, but if we want to use the lastest git, it can be installed through Homebrew.

brew install git
which git # check git path

For second command, you may find that the path still in /usr/bin/git.

Edit your shell configuration file(~/.bash_profile or ~/.profile or even ~/.zshrc) to place /usr/local/bin/git before /usr/bin

For example

export PATH="/usr/local/bin/git:$PATH"

start a new shell check git version by

git --version

Also remember to set SourceTree git to System provided.