Simple bash prompt that shows current git branch (if any) and colors the dollar sign in red if the last command exited with a nonzero status.

bash_profile.sh

_git_prompt() {
  local ref="$(command git symbolic-ref -q HEAD 2>/dev/null)"
  if [ -n "$ref" ]; then
    echo " (${ref#refs/heads/})"
  fi
}

_failed_status() {
  [ "$PIPESTATUS" -ne 0 ] && printf "$"
}

_success_status() {
  [ "$PIPESTATUS" -eq 0 ] && printf "$"
}

PS1='\[\e[0;31m\]\w\[\e[m\]$(_git_prompt) \[\e[1;31m\]$(_failed_status)\[\e[m\]$(_success_status) '