function fish_command_timer_compute_cmd_duration_str
  if [ $CMD_DURATION -lt 10000 ]
    return
  end

  set -l SEC 1000
  set -l MIN 60000
  set -l HOUR 3600000
  set -l DAY 86400000

  set -l num_days (math -s0 "$CMD_DURATION / $DAY")
  set -l num_hours (math -s0 "$CMD_DURATION % $DAY / $HOUR")
  set -l num_mins (math -s0 "$CMD_DURATION % $HOUR / $MIN")
  set -l num_secs (math -s0 "$CMD_DURATION % $MIN / $SEC")
  set -l cmd_duration_str ""
  if [ $num_days -gt 0 ]
    set cmd_duration_str {$cmd_duration_str}{$num_days}"d "
  end
  if [ $num_hours -gt 0 ]
    set cmd_duration_str {$cmd_duration_str}{$num_hours}"h "
  end
  if [ $num_mins -gt 0 ]
    set cmd_duration_str {$cmd_duration_str}{$num_mins}"m "
  end
  set cmd_duration_str {$cmd_duration_str}{$num_secs}s
  printf '%s ' $cmd_duration_str
end

function fish_right_prompt
  set_color brblack
  fish_command_timer_compute_cmd_duration_str

  set_color green
  printf '%s ' (prompt_pwd)
  set_color normal
end