Re: . and ..

[Luc Teirlinck <teirllm@dms.auburn.edu>]

Andreas Schwab wrote:

   Note that cd (without the -P option) in the POSIX shell works like Emacs.

The way I see it, without the -P option, the POSIX shell does not do
_any_ replacing of symbolic links in the path name.  So without the -P
option, the question of whether to do that before or after simplifying
away .. does not arise.  This is indeed a subtlety of cd one has to be
careful about.  It is explicitly documented in the bash manual.

Of course, the behavior of `expand-file-name' is documented too.
There is a difference however.  With `cd -L' vs `cd -P' one makes one
single choice.  In Emacs one makes a similar choice by calling or not
calling `expand-file-name', a function whose primary purpose is
something completely unrelated.  This is both inconvenient and
dangerous, as my ielm run illustrates.

I do _not_ suggest changing the behavior of the Emacs `cd' command,
because it indeed is consistent with the default -L behavior of the
POSIX shell.

Sincerely,

Luc.