@all_listing = qw ('folder/file.000001.jpg','folder/file.000002.jpg', ... , 'folder/file.039000.jpg','folder/file.040000.jpg');

foreach $kk (@all_listing) {
  next if $kk eq '';					# next on empty line
  next if ($kk =~ m|(.+)\/\..+| and $hidden);		# omit hidden (dot) files

  if ($kk =~ m|(.+)\/(\d+)\.(.+$)|) {		# match image sequence without prefix
    $path = $1; $num = $2; $ext = $3;
    print "$path:  $num.$ext\n" if ($debug);
    $pathpre = "$path/$ext";			# path and ext as the key ; adding ext so that if there are 2 seq with the same prefix and diff extension
    print ">> $pathpre\n" if ($debug);
    if (exists $seq{$pathpre}) {
      push (@range_tmp,$num);				# add element to array
    } else { 
      $seq{$pathpre} = $num;				# create hash
      @range_tmp = $num;				# empty array and add new element to it
    }
    $new_seq{$pathpre} = [@range_tmp];		# create new seq hash
    $ext{$pathpre} = $ext;			# create hash of extension
  } elsif ($kk =~ m|(.+)\/(.+?)([\._]+)(\d+)\.(.+$)|) {		# match image sequence
    $path = $1; $pre = $2; $div = $3 ; $num = $4; $ext = $5;
    print "$path:  $pre$div$num.$ext\n" if ($debug);
    $pathpre = "$path/$pre$div$ext";			# path, prefix, divider and ext as the key ; adding ext so that if there are 2 seq with the same prefix and diff extension
    print ">> $pathpre\n" if ($debug);
    if (exists $seq{$pathpre}) {
      push (@range_tmp,$num);				# add element to array
    } else { 
      $seq{$pathpre} = $num;				# create hash
      @range_tmp = $num;				# empty array and add new element to it
    }
    $new_seq{$pathpre} = [@range_tmp];		# create new seq hash
    $ext{$pathpre} = $ext;			# create hash of extension
  } elsif ($kk =~ m|(.+)\/(.+?)(\d+)\.(.+$)|) {		# match most image sequence, except this 7R01.0118762.dpx (number before dot) ; above regex takes care of this match
    $path = $1; $pre = $2; $num = $3; $ext = $4;
    print "$path:  $pre$num.$ext\n" if ($debug);
    $pathpre = "$path/$pre$ext";			# path, prefix and ext as the key ; adding ext so that if there are 2 seq with the same prefix and diff extension
    print ">> $pathpre\n" if ($debug);
    if (exists $seq{$pathpre}) {
      push (@range_tmp,$num);				# add element to array
    } else { 
      $seq{$pathpre} = $num;				# create hash
      @range_tmp = $num;				# empty array and add new element to it
    }
    $new_seq{$pathpre} = [@range_tmp];		# create new seq hash
    $ext{$pathpre} = $ext;			# create hash of extension

  } else {  
    push (@no_match,$kk);
  }
}