RVM or rbenv + git bash prompt config script

.bash_profile

[[ -s ~/.bashrc ]] && . ~/.bashrc
[ -f $(brew --prefix)/etc/bash_completion ] && . $(brew --prefix)/etc/bash_completion

# This loads RVM into a shell session. ( optional )
[[ -s "$HOME/.rvm/scripts/rvm" ]] && source "$HOME/.rvm/scripts/rvm"

# This load rbenv into the shell session ( optional )
export PATH="$HOME/.rbenv/bin:$PATH"
eval "$(rbenv init -)"
source ~/.rbenv/completions/rbenv.bash

# configure bash_prompt
[[ -s ~/.bash_prompt ]] && source ~/.bash_prompt

.bash_prompt

if [ "$PS1" ]
then

  __rvm_ps1 () {
    local gemset=$(echo $GEM_HOME | awk -F'@' '{print $2}')
    [ "$gemset" != "" ] && gemset="@$gemset"
    local version=$(echo $MY_RUBY_HOME | awk -F'-' '{print $2}')
    [ "$version" == "1.8.7" ] && version=""
    local full="$version$gemset"
    [ "$full" != "" ] && echo "$full$W"
  }

  __rbenv_ps1 () {
    rbenv_ruby_version=`rbenv version | sed -e 's/ .*//'`
    printf $rbenv_ruby_version
  }

  __ruby_manager_ps1 () {
    if [ "$(ruby_manager_installed)" == "rvm" ]; then
      echo "$(__rvm_ps1):"
    elif [ "$(ruby_manager_installed)" == "rbenv" ]; then
      echo "$(__rbenv_ps1):"
    else
      echo ""
    fi
  }

  color_txt_blue='\e[0;34m'
  color_txt_green='\e[0;32m'
  color_txt_yellow='\e[0;33m'
  color_txt_red='\e[0;31m'
  color_txt_white='\e[0;37m'
  color_txt_dark_grey='\e[90m'
  color_txt_default='\e[39m'

  ruby_manager_installed () {
    if [[ -f `which rvm` ]]; then
      echo "rvm"
    elif [[ -f `which rbenv` ]]; then
      echo "rbenv"
    else
      echo ""
    fi
  }

  ruby_selected () {
    [[ "$(ruby_manager_installed)" == "rvm" && `which ruby` != "/usr/bin/ruby" ]] ||
      [[ "$(ruby_manager_installed)" == "rbenv" && `rbenv version` != "system "* ]]
  }

  ruby_version_manager_active () {
    [ "$(ruby_manager_installed)" != "" ] && ruby_selected
  }

  ruby_version_name () {
    if ruby_version_manager_active; then
      echo "\[$color_txt_dark_grey\]$(__ruby_manager_ps1)"
    else
      echo ""
    fi
  }

  git_ps1_available () {
    [[ `type __git_ps1 | head -n 1` = "__git_ps1 is a function" ]]
  }

  git_repo_detected () {
    git status &> /dev/null
  }

  git_dirty () {
    git diff --quiet HEAD &>/dev/null
    [ $? == 1 ] && echo "*"
  }

  git_branch_name () {
    if git_ps1_available && git_repo_detected; then
      echo "\[$(git_branch_color)\]$(__git_ps1 "(%s$(git_dirty))")"
    fi
  }

  git_branch_color () {
    case `git symbolic-ref --short HEAD` in
      'master'|'production'|'prod')
        echo $color_txt_red
        ;;
      'development'|'dev'|'stage'|'staging')
        echo $color_txt_yellow
        ;;
      *)
        echo $color_txt_green
        ;;
    esac
  }

  current_working_dir () {
    #echo " \[$color_txt_white\]\w"
    echo "\[$color_txt_white\]\W"
  }

  bash_prompt_sign () {
    echo "\[$color_txt_default\]\$"
  }

  current_user_with_host () {
    if ruby_version_manager_active; then
      echo ""
    else
      echo "\[$color_txt_dark_grey\]\u@\h:"
    fi
  }

  set_bash_prompt () {
    PS1="$(ruby_version_name)$(current_user_with_host)$(current_working_dir)$(git_branch_name) $(bash_prompt_sign) "
  }

  export PROMPT_COMMAND=set_bash_prompt
fi