Path: utzoo!attcan!uunet!jarthur!usc!zaphod.mps.ohio-state.edu!wuarchive!udel!haven!decuac!bacchus.pa.dec.com!decwrl!brister
From: brister@decwrl.dec.com (James Brister)
Newsgroups: comp.lang.perl
Subject: Recursion problem
Message-ID: <BRISTER.90Nov4133946@westworld.decwrl.dec.com>
Date: 4 Nov 90 18:39:46 GMT
Sender: news@wrl.dec.com (News)
Organization: DEC Western Software Lab
Lines: 67
X-Checksum-Snefru:  3516ae01 b86d1121 1fed07c1 8f81b3e1

I'm writing a perl replacement for the lndir program that comes with X11.
The code (which follows) does a recursive walk of the directory tree and
seems to have two problems: 

1) When the subroutine lndir hits the first leaf directory, the $file
   variable in the foreach loop doesn't get incremented and an infinite
   loops results.

2) Does readdir reuire that an NFS file system be mount read-write? When I
   try this program with  a read-only file system directory as the first
   argument, I only get the lost+found directory displayed in the "mkdir"
   line. 

What's up here? 


---code starts---
#!/usr/local/bin/perl  -w

die "Usage: lndir sourcedir destdir" if ($#ARGV != 1) ;

$sourcedir = $ARGV[0] ;
$destdir = $ARGV [1] ;

die "$sourcedir is not a directory" if ( ! -d $sourcedir )  ;
die "$destdir is not a directory" if ( ! -d $destdir ) ;

# make sure last character is a backslash
$sourcedir .= '/' if (substr ($sourcedir,-1,1) ne '/') ;
$destdir .= '/' if (substr ($destdir,-1,1) ne '/') ;

do lndir ($sourcedir,$destdir) ;

exit 0 ;

sub lndir {
	local ($source,$dest) = @_ ;
	local ($dirlist,$oldfile,$newfile,$file) ;

	opendir ("DIR",$source) || die "Can't opendir $source" ;
	@dirlist = readdir ("DIR") ;
	closedir ("DIR") ;

	foreach $file (@dirlist) {
		next if ($file eq "." || $file eq "..") ;
		$oldfile = $source . $file ;
		$newfile = $dest . $file ;
		if (! -d $oldfile) {
			print "Doing symlink ($oldfile,$newfile) ;\n" ;
		} else {
			print "Doing mkdir ($newfile) ;\n" ;
			$oldfile .= '/' ;
			$newfile .= '/' ;
			do lndir ($oldfile,$newfile) ;
		}
	}
}

---code ends---


Thanks

James
--
James Brister                                           brister@decwrl.dec.com
DEC Western Software Lab., Palo Alto, CA    {uunet,sun,pyramid}!decwrl!brister