I did some changes in to your code & was able to achieve what you were looking.Here is the code 

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

use strict;
use warnings;
use diagnostics;
use Modern::Perl;
open FH, '<', 'Perl_file.txt' or die "Could not open file= $!";

while( <FH>) {                        
    chomp($_);                    
    my $line =$_;
    $line =~ s/\s+//gs;
    my $char_a = substr($line, 0, 2);
    my $char_b = substr($line,2,2);
    print $char_a;
    print $char_b;
                               
}

[download]

Data i inserted in to Perl_file.txt was 

Raam
larry
marry
sephali

[download]

OUTPUT:

Raamlarrmarrseph

In reply to Re: How to perform single operation to each line in file by nithins
in thread How to perform single operation to each line in file by rammohan

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