| Re: existing directories [message #14174 is a reply to message #14087] |
Mon, 25 January 1999 00:00  |
David Foster
Messages: 341
Registered: January 1996
|
Senior Member |
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Martin Schultz wrote:
>
> Hi,
>
> maybe something is blocking my mind right now, but I just can't think
> of a good (platform independent) way to test whether a directory exists
> or not. I am trying to write an 'install.pro' routine (not too fancy but
> at least with automatic backup of an old version and automatic creation
> of the target directory if not there). Actually, since I am spawning
> quite a few unix commands anyhow, a good Unix solution would be fine,
> too.
Martin -
Here are two routines that may help. First is a simple routine
that spawns a UNIX test command:
;----------------------------------------------------------- ------------------
;+
; Function VALID_DIR
;
; Function to determine whether string value specifies valid directory.
; Returns 1 if valid, 0 if not.
;-
;----------------------------------------------------------- ------------------
FUNCTION valid_dir, dir
; Go to UNIX and check if directory exists using test command
; Open a new shell to avoid aliases
spawn, ['/bin/sh -c "test -d ' + dir + '" && echo 1'], result
return, keyword_set( result )
END
Here is DIREXIST.PRO which I got from Phil Williams some time ago:
----------- cut here ---------------------------------------------
FUNCTION DirExist, list
;+
; NAME: DIREXIST
;
; PURPOSE: Determine which elements in list are directories.
;
; CATEGORY: File I/O
;
; CALLING SEQUENCE: result = direxist(list)
;
; INPUTS:
; list : a list of files (i.e. the result from list = FINDFILE())
;
; OPTIONAL INPUTS: none
;
; OUTPUTS: An array of the appropriate size. 1 indicates list(i) is a
; directory. 0 indicates that list(i) is a file.
;
; PROCEDURE:
; Get a file list
; IDL> list = findfile()
; IDL> dirs = direxist(list)
; Print which elements in list are directories
; IDL> print,where(dirs eq 1)
; 1 6 14 22
;
; MODIFICATION HISTORY:
; 27 Dec 96 Initial coding. PMW
; Use direxist.pro from David Fanning as a starting point.
; 28 Dec 96 Fixed bug. Now checking last entry in list. PMW
; 30 Dec 96 Fixed bug with last entry check. PMW
;-
; Save the current directory.
CD, Current=currentDirectory
foo = list
;print,'direxist dir = ', currentDirectory
; Use the Catch error handler to catch the case where we
; try to CD to a directory that doesn't exist.
results = intarr(n_elements(list))
i = -1
Catch, error
IF (error NE 0) THEN BEGIN
; Directory must not exist. Return 0.
bar = 0
goto, YIKES
ENDIF
; Try to CD to the directory. If it doesn't exist, an error occurs.
repeat begin
i = i+1
CD, foo(0), current = currentDirectory
; Well, the directory MUST exist if we are here! Change back to
; the current directory and return a 1.
bar = 1
YIKES:
results(i) = bar
CD, currentDirectory
if n_elements(foo) ne 1 then foo = foo(1:n_elements(foo) - 1)
endrep until n_elements(foo) eq 1
CATCH,/cancel
if n_elements(list) eq 1 then return, results
;--- Now do the last entry
i = i + 1
Catch, error
if (error ne 0) then begin
results(i) = 0
goto,done
endif
CD, foo(0), current = currentDirectory
;--- If were here its a directory
results(i) = 1
CD, currentDirectory
done:
RETURN, results
END
--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~
David S. Foster Univ. of California, San Diego
Programmer/Analyst Brain Image Analysis Laboratory
foster@bial1.ucsd.edu Department of Psychiatry
(619) 622-5892 8950 Via La Jolla Drive, Suite 2240
La Jolla, CA 92037
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~
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