Colored PS1 with git branch name based on whether current branch is dirty

.git-coloring.bash

# based on http://lancespeelmon.wordpress.com/2012/05/10/three-tips-for-creating-the-best-ever-git-command-line/

c_cyan=`tput setaf 6`
c_red=`tput setaf 1`
c_green=`tput setaf 2`
c_sgr0=`tput sgr0`
parse_git_branch ()
{
    if git rev-parse --git-dir >/dev/null 2>&1
    then
        git_status="$(git status 2> /dev/null)"
        branch_pattern="^# On branch ([^${IFS}]*)"
        remote_pattern="# Your branch is (.*) of"
        diverge_pattern="# Your branch and (.*) have diverged"
        # add an else if or two here if you want to get more specific
        if [[ ${git_status} =~ ${remote_pattern} ]]; then
          if [[ ${BASH_REMATCH[1]} == "ahead" ]]; then
            remote="↑"
          elif [ ${BASH_REMATCH[1]} == "behind" ]]; then
            remote="↓"
          fi
        fi
        if [[ ${git_status} =~ ${diverge_pattern} ]]; then
          remote="↕"
        fi
        if [[ ${git_status} =~ ${branch_pattern} ]]; then
          branch=${BASH_REMATCH[1]}
          echo "[${branch}${remote}]"
        fi
    else
        return 0
    fi
}
branch_color ()
{
    if git rev-parse --git-dir >/dev/null 2>&1
    then
        git_status="$(git status 2> /dev/null)"
        color=""
        if [[ ${git_status} =~ "working directory clean" ]]; then
            color="${c_green}"
        else
            color=${c_red}
        fi
    else
        return 0
    fi
    echo -ne $color
}
export PS1='\w\[${c_sgr0}\] \[$(branch_color)\]$(parse_git_branch)\[${c_sgr0}\]: '