#!/usr/bin/perl -w
use strict;

opendir(THISDIR,"e:\\perl\\comics\\");
my @comics=readdir(THISDIR);
close(THISDIR);

foreach (reverse(@comics)) {
   my ($name,$ext)=split(/\./,$_);
   if ($name=~/\d{3}/) {
      print '.';
   } elsif ($name=~/\d{2}/) {
      my $old=$name;
      $name=~s/(\d{2})/0$1/;
      rename "$old\.$ext", "$name\.$ext";
   } elsif ($name=~/\d{1}/) {
      my $old=$name;
      $name=~s/(\d{1})/00$1/;
      rename "$old\.$ext", "$name\.$ext";
   }
}

##</code><code>##

#!/usr/bin/perl
use warnings;
use strict;

chdir('e:/perl/comics/');
my @comics = glob('*.png');

foreach(@comics) {
    my $oldname = $_;
    $_ =~ s/(\d+)/sprintf("%03d",$1)/e;
    rename($oldname,$_) unless $oldname eq $_;
}