Re: RFE: stat(1) flag for learning the d_type value of a given file

[Pádraig Brady]

On 10/13/2014 08:56 PM, Eric Blake wrote:
> The Cygwin developers have been trying to improve some d_type hints
> given during readdir(), to return DT_DIR instead of DT_UNKNOWN for
> obvious directories, as an example.  But testing the patches for
> correctness has proved to be a bit of a challenge for testing.  On an
> IRC chat, we discovered that it is really difficult to find out what
> d_type lists for a given file without using a debugger or writing a
> custom program - most GNU code is using it as an optimization to avoid
> lstat(), but never directly outputs that the optimization took place.
> So the idea was raised: could we teach stat(1) a new format arg that
> would make it painfully obvious what d_type hint is associated with a
> given file?
> 
> Of course, such a format is not trivial, and must not be part of the
> default stat output.  Given 'stat --format=... a', you'd have to do
> readdir() on "." until you find "a", in order to get to the d_type.  But
> I couldn't think of any better utility to enhance to easily get at
> d_type information from the shell.  At least, stat(1) feels like a
> better choice than ls(1) for adding the enhanced output information.
> 
> What do you think? Should I spend time writing up a patch?

Maybe, though coreutils' tests also check d_type is available.
Would this suffice for cygwin?

http://git.sv.gnu.org/gitweb/?p=coreutils.git;a=blob;f=tests/d_type-check;hb=HEAD

cheers,
Pádraig.