bash prompt for rbenv & git

.bash_prompt

#!/bin/bash
# Add this to the end of .bashrc

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

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'

rbenv_installed () {
  [[ -f `which rbenv` ]]
}

ruby_selected () {
  [[ `rbenv version` != "system "* ]]
}

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

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

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

ruby_version_name () {
  if rbenv_installed && ruby_selected; then
    echo "\[$color_txt_dark_grey\]ruby-$(__rbenv_ps1)"
  fi
}

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

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

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

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

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

export PROMPT_COMMAND=set_bash_prompt