Show HN: Try my new Bash prompt

  PS1='\$ ' # short and sweet prompt

  old_cmdno=${old_cmdno-0}
  old_lines=${old_lines-0}
  old_cols=${old_cols-0}

  prepare_terminal()
  {
    stty rows $((LINES - 1))
    printf "\n\033[1A"
    old_lines=$LINES
    old_cols=$COLUMNS
  }

  update_status_line()
  {
    local exit=$?
    local getcmdno='\#'
    local cmdno=${getcmdno@P}
    local esc=$(printf "\033")
    local pwd=$PWD
    local dots=

    [ $LINES -eq $old_lines -a $COLUMNS -eq $old_cols ] || prepare_terminal

    local status_esc="$esc[7m$esc[m"

    while true; do
      [ "${pwd#/*/}" == "$pwd" ] && break
      local status="$esc[7m$(date +%m-%d/%H:%M)$esc[m $HOSTNAME $dots$pwd"
      local status_len=$((${#status} - ${#status_esc}))
      [ $status_len -le $COLUMNS ] && break
      pwd=${pwd#/}
      pwd=/${pwd#*/}
      dots='...'
    done

    status_len=$((${#status} - ${#status_esc}))

    [ $status_len -gt $COLUMNS ] && status=

    printf "${esc}7$esc[%s;1H$esc[K%s$esc[1;%sr${esc}8" $((LINES + 1)) "$status" $LINES
    if [ $exit -ne 0 -a $cmdno -ne $old_cmdno ] ; then
      printf "!%s!\n" $exit
    fi
    old_cmdno=$cmdno
  }

  PROMPT_COMMAND='update_status_line'