Bash prompt with time, path, git branch and exit status

.bashrc

function prompt_command {
    exitstatus="$?"

    BOLD="\[\033[1m\]"
    RED="\[\033[1;31m\]"
    GREEN="\[\e[32;1m\]"
    BLUE="\[\e[34;1m\]"
    PURPLE="\[\e[35;1m\]"
    CYAN="\[\e[36;1m\]"
    OFF="\[\033[m\]"

    time=`date +"%H:%M"`

    branch=`git symbolic-ref HEAD 2> /dev/null | sed -e 's/refs\/heads\///g'`
    if [ ! -z ${branch} ]; then
      if [ ${branch} == "master" ]; then
        branch=`echo " ${CYAN}${branch}"`
      else
        branch=`echo " ${PURPLE}${branch}"`
      fi
    fi
    changes=`git status -s 2> /dev/null | \
             wc -l | sed -e 's/ *//'`
    if [ ${changes} -eq 0 ]; then
      dirty=""
    else
      dirty="${RED}*${OFF}"
    fi

    prompt="\u@\h ${CYAN}${time}${OFF} \
${BLUE}\w${OFF}${PURPLE}${branch}${OFF}${dirty}"

    if [ ${exitstatus} -eq 0 ]; then
       PS1="${prompt} ${GREEN}\\$ ${OFF}"
    else
       PS1="${prompt} ${RED}\\$ ${OFF}"
    fi

    PS2="${BOLD}>${OFF} "
    
    dir=`pwd`
    title=`basename ${dir}`
    echo -n -e "\033]0;${title}\007"
}

PROMPT_COMMAND=prompt_command