#!/usr/bin/perl
# copy contents of 2 files alternatively to another file
$input1 = 'f1.txt';
$input2 = 'f2.txt';
 open (my $j, '<' , $input1 );
 open (my $l, '<' , $input2 );
 open (my $k, '>', 'f3.txt' );
 while (<$j>){
	print $k $_; # $_ is used to print the line till the end.
	while(<$l>){
		print $k $_;
	last;
	}}
 close $k;
close $j;
close $l;