Greetings Monks, I am having a hard time tracking down this issue I am having with the Net::SSH2 module. Basically, my code will read in a file containing information to be programmed into a menu-driven network device. The code will iterate through about 21 lines before simply exiting in the middle of a print statement. I am positive it is not due to faulty file input as I can replicate the issue with any file exceeding 21 lines. I'd like to know if there is any kind of debugging I can do that will show why the program is crashing. All code is contained below:

#!/usr/bin/perl

use 5.010;
use strict;
use warnings;
use Net::SSH2;
use Data::Validate::IP;

#Variables
my $host = $ARGV[0];
my $tacacsusername = $ARGV[1];
my $tacacspassword = $ARGV[2];
my $fh = $ARGV[3];
my $validator = Data::Validate::IP->new;
     
if (@ARGV != 4 || !$validator->is_ipv4($host)) {
    print "Invalid arguments, exiting.";
    exit;
}

open(my $data, '<', $fh) or die "Could not open '$fh' $!\n";

my $ssh = Net::SSH2->new();
$ssh->connect($host, 22);
$ssh->auth_password($tacacsusername, $tacacspassword);

if($ssh->auth_ok) {
    my $channel = $ssh->channel();
    $channel->blocking(0);
    $channel->shell();
    
    print $channel "network\n"; #Enter network context
    print $channel "ddelete\n"; #Clear DAT table
    print $channel "yes\n"; #Confirm clearing DAT sessions
    print $channel "b\n"; #Return to main context
    print "$_" while <$channel>; #Print output to console
        
    #Iterate the CSV file line by line
    while (my $line = <$data>) { 
        chomp $line;
        my @fields = split "," , $line;
        
        print $channel "subscribers\n"; #Enter subscriber context
        print $channel "add\n"; #Add subscriber
        print $channel "$fields[1]\n"; #Mac Address
        print $channel "$fields[0]\n"; #Hostname
        print $channel "1\n"; # Type of Profile 1=Device
        print $channel "$fields[2]\n"; #IP Address
        print $channel "\n"; #Subnet
        print $channel "\n"; #User Definable 1
        print $channel "\n"; #User Definable 2
        print $channel "\n"; #Upstream Bandwidth in kbps
        print $channel "\n"; #Downstream Bandwidth in kbps
        print $channel "\n"; #QOS Policy
        print $channel "$fields[3]\n"; #VLAN
        print $channel "\n"; #Proxy arp
        print $channel "\n"; #SMTP Redirection
        print $channel "b\n"; #Exit subscriber context
        print "$_" while <$channel>; #Print output to console
        
        if(scalar(@fields) > 5 && $fields[4] ne ''){
            print $channel "system\n"; #Enter system context
            print $channel "static\n"; #Enter static portmap context
            print $channel "add port\n"; #Add new portmap
            print $channel "$fields[2]\n"; #IP Address
            print $channel "$fields[4]\n"; #SNMP Internal port
            print $channel "$fields[1]\n"; #Mac Address
            print $channel "$fields[5]\n"; #SNMP External port
            print $channel "UDP\n"; #UDP on first pass for SNMP
            print $channel "\n\n"; #Remote IP, port
            print $channel "enable\n"; #Use access control
            print $channel "b\nb\n"; #Return to main context
            print "$_" while <$channel>; #Print output to console
        }
            
        if(scalar(@fields) > 7 && $fields[6] ne ''){
            print $channel "system\n"; #Enter system context
            print $channel "static\n"; #Enter static portmap context
            print $channel "add port\n"; #Add new portmap
            print $channel "$fields[2]\n"; #IP Address
            print $channel "$fields[6]\n"; #MGMT Internal port
            print $channel "$fields[1]\n"; #Mac Address
            print $channel "$fields[7]\n"; #MGMT External port
            print $channel "TCP\n"; #TCP on second pass for MGMT
            print $channel "\n\n"; #Remote IP, port
            print $channel "enable\n"; #Use access control
            print $channel "b\nb\n"; #Return to main context
            print "$_" while <$channel>; #Print output to console
        }
        
        if(scalar(@fields) > 9 && $fields[8] ne ''){
            print $channel "system\n"; #Enter system context
            print $channel "static\n"; #Enter static portmap context
            print $channel "add port\n"; #Add new portmap
            print $channel "$fields[2]\n"; #IP Address
            print $channel "$fields[8]\n"; #MGMT Internal port
            print $channel "$fields[1]\n"; #Mac Address
            print $channel "$fields[9]\n"; #MGMT External port
            print $channel "TCP\n"; #TCP on second pass for MGMT
            print $channel "\n\n"; #Remote IP, port
            print $channel "enable\n"; #Use access control
            print $channel "b\nb\n"; #Return to main context
            print "$_" while <$channel>; #Print output to console
        }
            
        else {
            print $channel "b\nb\n"; #Return to main context
        }
        
        print "$_" while <$channel>; #Print output to console
    }
    
    print $channel "b\n";
    print $channel "logout\n";
    print "$_" while <$channel>;
    print "\n";
    $channel->send_eof();
    $channel->close();
    $ssh->disconnect();
}
     
else {
     print "ERROR: Please verify credentials as the connection to the 
+gateway failed\n";
     }
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