oh-my-fish/themes/robbyrussell/fish_prompt.fish

function _git_branch_name
  echo (command git symbolic-ref HEAD ^/dev/null | sed -e 's|^refs/heads/||')
end

function _is_git_dirty
  echo (command git status -s --ignore-submodules=dirty ^/dev/null)
end

function fish_prompt
  set -l cyan (set_color -o cyan)
  set -l yellow (set_color -o yellow)
  set -l red (set_color -o red)
  set -l blue (set_color -o blue)
  set -l normal (set_color normal)

  set -l arrow "$red➜ "
  set -l cwd $cyan(basename (prompt_pwd))

  if [ (_git_branch_name) ]
    set -l git_branch $red(_git_branch_name)
    set git_info "$blue git:($git_branch$blue)"

    if [ (_is_git_dirty) ]
      set -l dirty "$yellow ✗"
      set git_info "$git_info$dirty"
    end
  end

  echo -n -s $arrow $cwd $git_info $normal ' '
end