Showing all changed file buffers in vim

So, editing a rails project in vim + NERDTree, I often edit several files and then browser refresh to check my work.  If I forget to save a particular file, it's problematic to check all the buffers. In #vim, they told me about ':ls', which shows all buffers in that session, with a + before the ones that are unsaved.  Also, ':ls +' will just show the unsaved buffers.

Also, the % indicates the current buffer, the # indicates the buffer you get to with a ':e#'.

TIL...