Show current pyenv python version in bash prompt, and also color virtual envs differently

.bash_profile

####
#### pyenv-virtualenv bash prompt customization
####


# pyenv
eval "$(pyenv init -)"

# pyenv-virtualenv:
eval "$(pyenv virtualenv-init -)"
export PYENV_VIRTUALENV_DISABLE_PROMPT=1
pyenvVirtualenvUpdatePrompt() {
    RED='\[\e[0;31m\]'
    GREEN='\[\e[0;32m\]'
    BLUE='\[\e[0;34m\]'
    RESET='\[\e[0m\]'
    [ -z "$PYENV_VIRTUALENV_ORIGINAL_PS1" ] && export PYENV_VIRTUALENV_ORIGINAL_PS1="$PS1"
    [ -z "$PYENV_VIRTUALENV_GLOBAL_NAME" ] && export PYENV_VIRTUALENV_GLOBAL_NAME="$(pyenv global)"
    VENV_NAME="$(pyenv version-name)"
    VENV_NAME="${VENV_NAME##*/}"
    GLOBAL_NAME="$PYENV_VIRTUALENV_GLOBAL_NAME"

    # non-global versions:
    COLOR="$BLUE"
    # global version:
    [ "$VENV_NAME" == "$GLOBAL_NAME" ] && COLOR="$RED"
    # virtual envs:
    [ "${VIRTUAL_ENV##*/}" == "$VENV_NAME" ] && COLOR="$GREEN"

    if [ -z "$COLOR" ]; then
        PS1="$PYENV_VIRTUALENV_ORIGINAL_PS1"
    else
        PS1="($COLOR${VENV_NAME}$RESET)$PYENV_VIRTUALENV_ORIGINAL_PS1"
    fi
    export PS1
}
export PROMPT_COMMAND="$PROMPT_COMMAND pyenvVirtualenvUpdatePrompt;"

## Recommanded pyenv setup:
## run this once, don't put it in .bash_profile (or similar) files!
# $ pyenv global system
# $ cd $HOME
# $ pyenv local 2.7.11  # or which ever version you like having as default