sample code for git branch on prompt (zsh) - copied from some source elsewhere; sorry unable to remember to give credit

.zshrc

# git branch display
git_prompt()
{
    if ! git rev-parse --git-dir > /dev/null 2>&1; then
        return 0
    fi

    git_branch=$(git branch 2> /dev/null | sed -n '/^\*/s/^\* //p')

    if git diff --quiet 2> /dev/null >&2; then
        git_color="$fg_no_bold[green]"
    else
        git_color="$fg_no_bold[red]"
    fi

    echo ":%{$git_color%}$git_branch%{$reset_color%}"
}

autoload -U promptinit
promptinit

autoload colors zsh/terminfo
colors

setopt prompt_subst

# not sure this is needed for osx
case $TERM in
    *xterm*)
        precmd () {print -Pn "\e]0;%n@%M: %~\a"}
        ;;
esac

# customize to your content
PROMPT='[%B%{$fg_bold[green]%}%1d%{$reset_color%}%b$(git_prompt)] '