This is a farily simple method:

declare @files table (cmdout nvarchar(100) )

insert into @files ( cmdout )

-- Get filenames excluding directories

exec master.dbo.xp_cmdshell 'dir C:\ /b /a:-d'

select cmdout from @files where cmdout is not null order by cmdout

Results:

cmdout

-------------------

AUTOEXEC.BAT

BOOT.BAK

boot.ini

cmldr

CONFIG.SYS

IO.SYS

license.txt

MSDOS.SYS

ntdetect.com

ntldr

pagefile.sys