use warnings;
use strict;
use Cwd;

my $cwd = cwd() ;

#-- get the subdirs and files
opendir ( DIR, $cwd ) || die "$!: dir $cwd doesn't exist!\n";
my @dirs  = grep { -d && $_ ne "." && $_ ne ".." } readdir DIR;
rewinddir DIR;
my @files = grep { -f } readdir DIR;
close DIR;

$cwd =~ s{/}{\\}g;
if ( @dirs )
{
 $cwd .= '\\'. shift @dirs;
}
elsif ( @files )
{
 $cwd .= '\\' . shift @files;
}
else
{
 $cwd .= '\\.';
}

#-- pop the explorer window
exec "explorer.exe /e,/select," . $cwd;