Add these lines to your startup bash file (e.g. ~/.bash_profile or ~/.bashrc):
function parse_git_dirty {
[[ $(git status 2> /dev/null | tail -n1) != "nothing to commit, working directory clean" ]] && echo "*"
}
function parse_git_branch {
git branch --no-color 2> /dev/null | sed -e '/^[^*]/d' -e "s/* \(.*\)/[\1$(parse_git_dirty)]/"
}