Faster version of __git_ps1 if you only want current branch

git_ps1_fast.sh

#!/bin/bash

function git_ps1_fast() {
  local dir="$PWD"
  local git_dir

  until [[ -z "$dir" ]]; do
    git_dir="$dir/.git"
    if [[ -d "$git_dir" ]]; then
      echo " (`git rev-parse --abbrev-ref HEAD`)"
      return
    fi

    dir="${dir%/*}"
  done
}

PS1='\u@\h:\w$(git_ps1_fast) \$'