FINDFILE and Unix

[dsreyn(at)ll.mit.edu (Doug Reynolds)]

I recently had some problems with the FINDFILE function.  First of all, the
Online Help documentation contains an error:

   Under UNIX, to refer to all of the files in a directory only, use
   FINDFILE('/File_Specification/*.*'). To include all the files in any
   subdirectories, use FINDFILE('/File_Specification/*')

However, under Unix, a call with "*.*" omits any files that do not include "."
in their name.  In addition, searching for "*.*" does not prevent searching
through subdirectories - if a directory name contains ".", FINDFILE will
include any files within it.

Now, the reason I was looking through the documentation in the first place is
that FINDFILE can not do what I was trying to do.  We have a directory that
contains 97 subdirectories starting with "f" - "f300", "f301", "f302", etc.  I
wanted to get a list of all of these subdirectories.  Here is what happened:

	IDL> files = findfile ("/users/username/f*")
        IDL> help, files
        FILES               STRING    = Array[1767]

The problem is that in addition to returning the directory names I wanted,
FILES also included all the files and subdirectories in these directories.
Unfortunately, under Unix, there is no way to make FINDFILE return a directory
name without also including the contents.

My guess is that FINDFILE is just an interface to the "ls" command.  If so, I
think it would be nice if a keyword could be added to make FINDFILE execute
either "ls" or "ls -d", depending on whether or not the user wants to include
subdirectory contents.  For example:

	files = findfile ("/users/airi/f*", /norecurse)
	files = findfile ("/users/airi/f*", /recurse)

In the meantime, I have written a FINDFILE replacement, which I have included
below.  On an OS other than Unix it just calls FINDFILE, but Unix users have
the option of using a /RECURSE keyword to enable or disable subdirectory
searches.  Any comments / feedback would be appreciated.

Doug Reynolds

;+
; NAME:
;      llfindfile
; PURPOSE:
;      Replacement for IDL's FINDFILE function, which does not work properly
;      under Unix.
; EXAMPLES:
;      1. List all files ending with .dat in the current directory:
;         files = llfindfile ('*.dat')
;      2. List all files in the entire /users/airi hierarchy, and return
;         the number of entries:
;         files = llfindfile ('/users/airi', /recurse, count = count)
; CALLING SEQUENCE:
;      files = llfindfile (filespec, [/recurse] [,count=entries])
; INPUTS:
;      path         The file specification to match (can include wildcards)
; OPTIONAL INPUTS:
; KEYWORD PARAMETERS:
;      /help        Prints this header
;      /recurse     If set, causes the search to include files and
;                   subdirectories within matched directories
; OUTPUTS:
; OPTIONAL OUTPUTS:
;      count        Returns the number of files found
; COMMON BLOCKS:
; SIDE EFFECTS:
;      IDL's FINDFILE appends a colon to a name if it is a directory; this
;      routine appends a '/'.
; RESTRICTIONS:
; PROCEDURE:
; MODIFICATION HISTORY:
;      000131  DSR  Written.
;-
function llfindfile, path, recurse = recurse, count = count, help = help

;   Help

   if keyword_set(help) then begin
      doc_library, 'llfindfile'
      return, 0
   endif

   if !version.os_family ne 'unix' then begin
      return, findfile (path, count = count)
   endif else begin
      if n_elements (path) eq 0 then command = 'ls -F' else begin
         if not keyword_set (recurse) then command = 'ls -Fd ' else $
           command = 'ls -F '
         command = command + path
      endelse
      spawn, command, result
      count = n_elements (result)
      return, result
   endelse
end