pack() and unpack function in PERL

Content of test-file.txt
------------------------
20080331EJUSD00 0003372500000010750000000000000000000000
20080331 SUSD0000 87673600001148531000000000000000000000
20080331XZUSD00000 0000000000000000000000000000000000000
200 0331XZUSD0000000000000000000000000000000000000000000
20 0331XZUSD0000000000000000000000000000000000000000000

Script name: try-unpack.pl

#!/usr/bin/perl

use warnings;
use strict;

my $xf = './test-file.txt';

open FH, $xf or die " Can not open the file : $! \n";
while()
{
chomp $_;
my ($a, $b, $c, $d) =unpack("A4 A4 A4 A8", $_);
print $a . "\t" . $b . "\t" . $c . "\t" . $d . "\n";
}

Output:
bash-2.05$ ./try-unpack.pl
2008 0331 EJUS D00 0003
2008 0331 SUS D0000 87
2008 0331 XZUS D00000 0
200 0331 XZUS D0000000
20 0331 XZUS D0000000


====================================================================
Script Name: try-pack.pl

#!/usr/bin/perl

use warnings;
use strict;

my $xline;
die " Not enough user specified inputs : $! \n" unless @ARGV == 4;
$xline = pack("A5 A4 A3 A2", $ARGV[0], $ARGV[1], $ARGV[2], $ARGV[3]);
print $xline . "\n";
$xline = pack("a5 a4 a3 a2", $ARGV[0], $ARGV[1], $ARGV[2], $ARGV[3]);
print $xline . "\n";


Output:
bash-2.05$ ./try-pack.pl KUMAR PRA RA BROTHER
KUMARPRA RA BR
KUMARPRARABR