Add Dashes to date in file name. Takes: "part_part_20120513_part_part.ext" and makes: "part_part_2012-05-13_part_part.ext".

addDashes.pl

sub addDashes
{
  my $originalFileName = shift;

  #split along uscores into array
  my @parts = split('_',$originalFileName);

  # take the third index of the array and add dashes in this pattern ####-##-## and put it back in the array
  $parts[2] = join('-', unpack('A4A2A2', $parts[2]));

  # put the whole thing back together
  my $formattedFileName = join('_', @parts);
  return $formattedFileName;
}