[Rd] Question about Unix file paths

Kurt Hornik Kurt.Hornik at wu-wien.ac.at
Wed Nov 26 10:05:42 MET 2003

>>>>> Prof Brian Ripley writes:

> On Mon, 24 Nov 2003, Duncan Murdoch wrote:
>> >Duncan Murdoch <dmurdoch at pair.com> writes:
>> >
>> >> Gabor Grothendieck pointed out a bug to me in list.files(...,
>> >> full.name=TRUE), that essentially comes down to the fact that in
>> >> Windows it's not always valid to add a path separator (slash or
>> >> backslash) between a path specifier and a filename.  For example,
>> >> 
>> >> c:foo
>> >> 
>> >> is different from
>> >> 
>> >> c:\foo
>> >> 
>> >> and there are other examples.
>> I've committed a change to r-patched to fix this in Windows only.
>> Sounds like it's not an issue elsewhere.

> 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.

>> Gabor also suggested an option to use shell globbing instead of
>> regular expressions to select the files in the list, e.g.
>> list.files(dir="/", pattern="a*.dat", glob=T)
>> This would be easy to do in Windows, but from the little I know about
>> Unix programming, would not be so easy there, so I haven't done
>> anything about it.

> It would be shell-dependent and OS-dependent as well as a retrograde
> step, as those who wanted to use regular expressions no longer would
> be able to.

Right.  In any case, an explicit glob() function seems preferable to
me ...


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