Anonymous

    function! MakeStamp()
	"ISO timestamp
      let time = strftime("%Y-%m-%d at %H:%M:%S")
    exe '%s/Last updated on \zs\d\{4}\-\d\{2}\-\d\{2} at \d\{2}:\d\{2}:\d\{2}/'.time.'/ig'
      return ""
    endfunction
     
    map ,t :call MakeStamp()<CR>