From: patrick-may@... (Patrick May)
Date: 2002-04-03T06:13:59+09:00
Subject: a note on the . and .. discussion

I just realized that unix commands do not recognize the "." and ".."
when you execute a command.  ls will show "." and ".." as directory
entries, but chmod, chgrp, grep, etc. all ignore "." and ".." when you
do a "chmod 666 *", etc.

Adding to the apparent inconsistency -- even the root dir has "." and
".." entries.  I would think that if "." and ".." were to provide
information, then root wouldn't have a ".."

Since these entries are "invisible" to most commands, and since these
entries don't seem to provide consistent information, they smell like
a special case to me.

The first question I ask is:

Why are they a special case?  

- to provide a way of navigating the filesystem tree

This leads to my next (more on topic) question:

Is there a better way of doing this in Ruby?

- IMHO, I think that aDir.parent is cleaner than aDir[".."].  I also
think that "." and ".." should continue to be valid "glob"
expressions.

The point is that unix treats these entries as a special case.  If
these entries are special cases in unix, then it makes sense for us to
treat them as special cases in Ruby.

~ Patrick