fix-git

#!/bin/sh

# Converts string such as "git version 2.6.4 (Apple Git-63)" into "264"
function numeric_git_version {
  git --version | sed 's/git version //g' | sed 's/ (Apple Git-[0-9]*)//g' | sed 's/\.//g'
}

function fix_git {
  echo "Ensuring that /usr/local is writable for homebrew. Please enter your password:"
  sudo chown -R $(whoami):admin /usr/local
  
  echo "Updating homebrew..."
  brew update

  if [[ -z "$(brew list -1 | grep '^git$')" ]]; then
    echo "Installing newest git using homebrew..."
    brew install git
  else
    echo "Upgrading to newest git using homebrew..."
    brew upgrade git
  fi

  echo "Symlinking homebrew git to Xcode git..."
  sudo mv /Applications/Xcode.app/Contents/Developer/usr/bin/{git,oldgit}
  sudo ln -s /usr/local/bin/git /Applications/Xcode.app/Contents/Developer/usr/bin/git

  echo "Done! Please open a new terminal tab/window to have changes take effect."
}

if [[ "$(numeric_git_version)" -le 273 ]]; then
  echo "WARNING: You are using a vulnerable version of git."
  echo "Attempting to fix automatically..."
  fix_git
else
  echo "You are using a safe version of git. Good job!"
fi