Mac OS Yosemite Git aware (two-line) bash prompt

mac-os-git-aware-bash-prompt.sh

# settings for the main prompt
BLUE="\[\e[44;36m\]"
PATH_SHORT="\w"
COLOR_RESET="\[\e[0m\]"
NEW_LINE="\n"

# RAG colors indicating git status
RED="\[\033[0;31m\]"
AMBER="\[\033[0;33m\]"
GREEN="\[\033[0;32m\]"
NO_COLOR="\[\033[0m\]"

# thanks https://gist.github.com/maumercado for the below functions!
function parse_git_branch () {
  git branch 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/(\1)/'
}

function set_git_branch () {
  # capture the output of the "git status" command
  git_status="$(git status 2> /dev/null)"
  # set color based on clean/staged/dirty
  if [[ ${git_status} =~ .*"working directory clean".* ]]; then
    B_STATE="${GREEN}"
  elif [[ ${git_status} =~ .*"Changes to be committed".* ]]; then
    B_STATE="${AMBER}"
  else
    B_STATE="${RED}"
  fi
}

prompt_cmd () {
  set_git_branch
  PS1="$BLUE$PATH_SHORT$COLOR_RESET ${B_STATE}\$(parse_git_branch)$NO_COLOR$NEW_LINE[\u@\h] $ "
}

# override Xcode's git version with a newer one (installed by SourceTree)
export PATH="/usr/local/git/bin:/usr/local/bin:/usr/bin:/usr/local/sbin:$PATH"

PROMPT_COMMAND=prompt_cmd