Question about Unix file paths

I think there are some potential issues with doubling separators and final
separators on dirs.  On Unix file systems /part1//part2 and /path/to/dir/
are valid.  However, file systems on Unix may not be Unix file systems:
examples are earlier MacOS systems on MacOS X and mounted Windows and 
Novell systems on Linux.  I would not want to assume that all of these
combinations worked.

This is something that R could not do reliably by itself.  The code I
committed checks the final character in the path, and if it's "/", "\"
or ":" doesn't add a path separator.  However, both "C:" and "C:\" are
valid directory names in standard Unix file systems, so the test would
do the wrong thing there.

I think people who mount strange file systems will just have to expect
occasional glitches.  The only way I can see around this is to add
another argument to list.files() to say whether to add a path
separator, but it would be so rarely used that it doesn't seem to be
worth the effort.

Duncan Murdoch