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

#Open data file and put it into variable
open FILE, "<data.txt";
my $string = do {local $/; <FILE> };

#Set offset if there is a header record and add it to initial position
my $offset = 0;
my $currentpos = 0 + $offset; 

#Set lastpos = length of data
my $lastpos = length($string);

#Read until end of data 
while ($currentpos < $lastpos) {  

#Grab record length within data
my $recordlength = (substr $string, $currentpos, 4);  

#Grab record type which is 5th char
my $recordtype = substr $string, $currentpos+4, 1;  

#Using record length grab the record and put it into variable
my $fragment = substr $string, $currentpos, $recordlength;  

#Calculate starting position for next record .. not used at present
my $nextstartpos = $currentpos + $recordlength + 1;  

#Use if clause to identify only $ record types and print the record data
if ($recordtype eq '$')
{
print " record type: $recordtype\n";  
print " data: $fragment\n";  

#Inrement starting position for the next loop
$currentpos =  $currentpos + $recordlength;
}
}