Re: Curious FindFile behavior

[mallors(at)msfc.nasa.gov (Robert S. Mallozzi)]

In article <73holl$fts@milo.mcs.anl.gov>,
	lesht@ANLER.ER.ANL.GOV (Barry Lesht) writes:
> I'm running IDL5.1 on an SGI (IRIX6.2).  I'm using FindFile to create
> an array of data filenames that I can pass to some processing code.
> There are (as it turns out) 515 files in the directory I'm searching.
> The filenames are all of the form xxxxxxxxx.xx.yymmdd.hhmmss.cdf. I
> get the following from FindFile-
> 
> IDL> files=FindFile('*.*', COUNT=nf)
> IDL> PRINT, nf
>            0
> IDL> files=FindFile('*.cdf', COUNT=nf)
> IDL> PRINT, nf
>            0
> IDL> files=FindFile('*98*.cdf', COUNT=nf)
> IDL> PRINT, nf
>            0
> IDL> files=FindFile('*980*.cdf', COUNT=nf)
> IDL> PRINT, nf
>          425
> IDL> files=FindFile('*981*.cdf', COUNT=nf)
> IDL> PRINT, nf
>           90
> 
> I don't see why cases 2 and (especially) 3 didn't result in nf=515.
> Can anyone explain this?  Thanks.

This problem should really be addressed by RSI.  What is 
happening, I believe, is that FINDFILE is spawning a shell to
get the file list via something like "ls".  However, the shell
has limits on the byte length of command line arguments - for
long lists, the command will fail.  RSI should really be
using another UNIX tool meant for this job - that is the
"find" command.  See the UNIX man pages exec(2), find(1), 
xargs(1) for more info. 

I have a program FINDFILES on my web page that should work
for you, and also "fixes" searching for files recursively.
See http://cspar.uah.edu/~mallozzir/idl/idl.html



-- 
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Robert S. Mallozzi                                          256-544-0887
                                                         Mail Code ES 84
Work: http://www.batse.msfc.nasa.gov/       Marshall Space Flight Center 
Play: http://cspar.uah.edu/~mallozzir/              Huntsville, AL 35812
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