printf("%06d\n",$_) for (123, 1234, 12345, 123456);

my $val = sprintf("%06d",123);

##</code><code>##

my $name = '012345';
my ($three) = $name =~ /^(\d\d\d)/;

##</code><code>##

use strict;

while (<DATA>) {
   chomp;
   my ($numbs) = $_ =~ /^(\d+)/;
   my $formatted = sprintf("%06d",$numbs) . '.jpg';
   my ($dir) = $formatted =~ /^(\d\d\d)/;
   print "filename: $formatted\t\tdirname: $dir\n";   
}

__DATA__
123.jpg
1234.jpg
12345.jpg
123456.jpg