#!/usr/bin/perl
use strict;

my @emptyfiles = grep { /^\d+$/ } grep { -f } glob '*';
foreach my $emptyfile (@emptyfiles) {
  my $previous = $emptyfile - 1;

  if ((-z $emptyfile) and (-f $previous)) {
    print "found previous conformation: $previous \n";
    print "found new conformation: $emptyfile \n";
  } # if -z loop.

} #foreach loop.