rename.pl

#!/usr/bin/env perl
use v5.10;
use utf8;
use strict;
use warnings;
use autodie;
use File::Copy;
use Cwd;


say("Application started.");

my $dir = cwd();
if (@ARGV == 1) {
	$dir = shift (@ARGV);
}
say("Directory: $dir");

say("Opening directory...");
opendir(DIR, $dir) or die "can't open dir $dir: $!";

my $counter_renamed = 0;
my $counter_ignored = 0; 
say("Beginning bulk rename...");
while (defined(my $file = readdir(DIR))) {
	if($file =~ /\.(tga|png|jpe?g)/i){
		my $new_file = $file;
		$new_file =~ s/\d{1}_//i;
		$new_file =~ s/([0-9]+)/sprintf('%06d',$1)/ige;
        if ($file eq $new_file){
            say ("Ignored file '$file' (New filename would not differ from current filename)");
            $counter_ignored++;
            next;
        }
	    if (move("$dir/$file", "$dir/$new_file")){
	    	$counter_renamed++;
	    	say("Renamed file '$file' -> '$new_file'");
	    	}
	    else{
	    	say("Couldn't rename file '$file': $!");
	    }
    }
    else{
        $counter_ignored++;
    	say("Ingored file '$file' (No image file)");
    }
}
my $counter_sum = $counter_renamed + $counter_ignored;
say("Finished bulk rename");
say("Processed files:\t$counter_sum");
say("Renamed files:\t$counter_renamed");
say("Ignored files:\t$counter_ignored");
say("Closing directory...");
closedir(DIR);

say("Exiting");