In Ubuntu, when I make change to directories or files outside emacs, it seems that emacs doesn't get the update.
For example, C-x C-f can't track the current directory which was just moved elsewhere outside emacs.
Another example: in a shell created by C-x shell, the autocompletion of directory or file name doesn't work, if the current directory has been moved elsewhere outside emacs.
Can I make emacs get the update made outside emacs? Thanks.