#!/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 da
+ta
if ($recordtype eq '$')
{
print " record type: $recordtype\n";  
print " data: $fragment\n";  

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

[download]

Any ideas?

I've commented to try and explain what it does, it's working through a file identifying records of different types within it and printing certain record types to screen however it just hangs after printing the 1st record for me

Thanks!

In reply to Can someone tell me why this hangs?? by monty77

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